temperature problems?

[tbmdsd]

Anybody having overheating problems? Mine (in hot weather and sometimes not so hot) the temp goes up over the 210 degree and climbs unless I start cranking the heat and laying off the throttle. Any ideas? Can I use Water Wetter with Dexcool?

[02EnvoySLE Guy]

I use RedLine Water Wetter in my Dexcool, have in multiple vehicles now. It's perfectly safe. :m2:

[Dave]

210 really isn't too hot as long as it drops when you start moving. Boiling point of plain water is 212, with anti freeze around 260.

[tbmdsd]

210 really isn't too hot as long as it drops when you start moving. Boiling point of plain water is 212, with anti freeze around 260.

Well I know, actually I couldn't remember the number I just know that there is a normal operating temp that it usually stays at and when it gets hot it climbs fast past the normal spot to a point that I know it is starting to overheat if I don't do anything.

[lowTB04]

This might go back to the thread POOR A/C at idle. I had my clutch fan replaced because our A/C at idle blowed hot air. Before we did this our TB never got above 210, and that even when we towed our boat in 100+ degree wheather here in the central valley of California. Now it goes above 220 while the air is on and just as hot or hotter when we tow our boat now. We are going to take it back to the dealer later this week. Also changing the clutch fan has not helped our A/C problem either just made it run hotter. :confused:

[sallen]

wow it made it hotter, dont know if i want to get the ac looked at then if this is what happens mine never runs hot at all, just sits left of middle

shay

[Envoy Fan]

This might go back to the thread POOR A/C at idle. I had my clutch fan replaced because our A/C at idle blowed hot air. Before we did this our TB never got above 210, and that even when we towed our boat in 100+ degree wheather here in the central valley of California. Now it goes above 220 while the air is on and just as hot or hotter when we tow our boat now. We are going to take it back to the dealer later this week. Also changing the clutch fan has not helped our A/C problem either just made it run hotter. :confused:

If they did not use part #15293048 for the new fan clutch, they just put in another bad one like you had before. :m2:

[Wxman]

I have had high temperature problems. I live in Tucson and whenever the outside temp gets in the upper nineties or higher the engine begins to run hot. (2003, EXT, 5.3L) I regularly see engine temps of 230 or 235, not loaded or towing. Fan clutch has been replaced 3 times, twice with the new version. The PCM has been reprogramed/updated, the system flushed and thermostat replaced. Supposedly the flow/water pump checks OK. This is the fourth time the truck has been in for running hot and it has been at dealer for exactly four weeks this time.

Not happy. Want the truck back fixed. GM/dealer have no clue right now.

Wxman

[Dave]

Is 235 idling or when you are moving? It does sound like you have a problem. I can idle in 100 degree heat for around 30 minutes with my 5.3 and the temp gage never goes up more than 2 small marks past half way.

[tbmdsd]

I have had high temperature problems. I live in Tucson and whenever the outside temp gets in the upper nineties or higher the engine begins to run hot. (2003, EXT, 5.3L) I regularly see engine temps of 230 or 235, not loaded or towing. Fan clutch has been replaced 3 times, twice with the new version. The PCM has been reprogramed/updated, the system flushed and thermostat replaced. Supposedly the flow/water pump checks OK. This is the fourth time the truck has been in for running hot and it has been at dealer for exactly four weeks this time.

Not happy. Want the truck back fixed. GM/dealer have no clue right now.

Wxman
Mine runs hot like that too, when not towing and with the AC on. It never used to do that. I towed a heavy trailer 2200 miles across country when the truck had about 27-30,000 miles and no problems. Now I have 62,000 miles and can barely run the AC for very long if it is 90+ degrees out

[jdb1937]

Isnt it interesting that a vehicle with a/c runs hot in hot weather - and then you cannot run the a/c? What good is the a/c if you cannot run it? I cannot stand the fact that i cannot run the a/c in 100 degree weather without overheating! I have had this problem many times on vehicles- and i have found out there are some things you can do.

Of course, the first thing to do is make sure your stock cooling system is operating normally. If your water pump is bad, for ex, you will of course need it fixed. But it looks like some people here have done all of this- and they are still running hot.

There are several options here. Myself- i run a low-temperature thermostat in all my vehicles, 160 degree. The water temp is always 180 degrees in my vehicles. If i have a vehicle without a water temp gauge- i always install a mechanical water temp gauge that reads out in real numbers- i use auto meter #2333.

I have had a lot of problems with fan clutches. I've yet to find one that works well, and correctly. So i always remove them and use a flex a lite electric fan. These are very reliable and have a very easy to use installation diagram. I just remove the stock fan and radiator- (i measure the area where the radiator is carefully to see what the biggest radiator i can find that will fit in there. Then i take the radiator to my radiator man and he trades me my stock, smaller radiator for a bigger one- or in some applications- he adds a new radiator core the radiator i have for added cooling)

With the stock fan, fan shroud, and radiator removed, you'll have a lot of room to work on other components of the engine. Got about 80,000 miles on your trailvoy?? Good time to get a new water pump. Get a high performance pump if one is available by checking with www.summitracing.com Change your engine drive belt now, if needed, and notice how easy that is to do.

Now mount your flex a lite "black majic" fan (this is the model i would use on a trailvoy) to your radiator, and then reinstall the assembly back in your trailvoy. If you got a bigger radiator, you may need to move a wire or two, or etc., to squeeze in the bigger radiator. Now notice how much more room there is to work on your vehicle without that fan shroud/fan in the way. Your water pump will also last a lot longer without that heavy fan clutch hanging off of it. And your engine will warm up much quicker without the fan turning, cooling it off before it can warm up. And you'll get a little more power and a little better gas mileage without the fan being turned by the engine. Keep in mind- the electric fan will not increase your cooling unless your fan clutch is bad. If you have a bad fan clutch- the electric fan will cure that problem- and you will get much better cooling. If not - the electric will not increase your cooling capacity much- but still well worth it. I've been running my flex a lite black majic in my Ford Ranger for three years- and for 10 years in the previous vehicle - GMC S-15 - all with the SAME fan! That is one tough fan. I promise a fan clutch will not last that long.

Now - make a note of what water temp your trailvoy is running at- and run the a/c wide open, idle the engine 30 minutes like at a stop light, etc. If it goes over 180 degrees (or over 210 if you run a stock thermostat) then you need to go to the next step. You need an engine oil cooler- again, the best ones i have found are at www.summitracing.com You'll also need a flex a lite fan to go either in front or in back of your oil cooler. Just measure the front end of your trailvoy and get the biggest oil cooler that will fit. Make sure your oil cooler is 1.5" thick and with 5/8" tubes- believe me- i learned this the hard way. I wouldn't give anything for the cheap 3/4" thick oil cooler- it doesnt do anything. Get the biggest length X width that will fit, and 1.5" thick. Be sure to get the type of oil cooler with "barbed" ends so that you can cut the hose any length you like- do NOT get fittings for your oil cooler- again, practical experience shows me all they do is leak. With barbed fittings- i can cut the hose to any length i need and they never leak. Be sure to use the high pressure "fuel line" quality hose clamps, stainless steel- you can get them at any good quality auto parts store like advance, NASA, Pep Boys. And they arent that expensive.

Now your oil capacity will be increased, and esp if you are are also running 180 degree water temp- you'll notice your oil lasts a lot longer before it gets black. Oil change intervals are lengthened. Also- the cooler underhood environment means that it is easier for your a/c compressor to get cold. Which do you think is easier on your a/c- an underhood temp of 180 degrees- or a smoking hot 240 degrees??

I did all of the above modifications on several vehicles, most notably a 1996 Ford Ranger 4.0 V-6. Boy does that engine ever overheat stock! (240 is when i shut it down- it was still climbing) But now, (with a 5.0 V-8 radiator, big summitracing engine oil cooler with flex a lite fan, 160 stat, mechanical water temp gauge, and also two more fans in front of the a/c condensor- total of 4 electric fans) it runs 180 degrees water temp, never, ever pings on 87 octane pump gas, runs with much more pep.

Now, when i step out of the truck and the air temp is more than 100 degrees- my eyeglasses immediately frost right over! I'd do everyone of those modifications over again. It is simply a different truck.

Now i am sure people out there are not going to do all of those things- but thought it might help someone if they did one of them. Good luck and let me know how your projects go. Sorry for the long post.

[Envoy Fan]

jdb1937 interesting reading. Others have wanted to go the electric fan route, only to find out their GMT360/370 won't run, because the computer did not sense the OEM fan. Also, don't know of a 160 degree thermostat available for the 4.2L engine. :m2:

[Black Ice]

Isnt it interesting that a vehicle with a/c runs hot in hot weather - and then you cannot run the a/c? What good is the a/c if you cannot run it? I cannot stand the fact that i cannot run the a/c in 100 degree weather without overheating! I have had this problem many times on vehicles- and i have found out there are some things you can do.

Of course, the first thing to do is make sure your stock cooling system is operating normally. If your water pump is bad, for ex, you will of course need it fixed. But it looks like some people here have done all of this- and they are still running hot.

There are several options here. Myself- i run a low-temperature thermostat in all my vehicles, 160 degree. The water temp is always 180 degrees in my vehicles. If i have a vehicle without a water temp gauge- i always install a mechanical water temp gauge that reads out in real numbers- i use auto meter #2333
I have had a lot of problems with fan clutches. I've yet to find one that works well, and correctly. So i always remove them and use a flex a lite electric fan. These are very reliable and have a very easy to use installation diagram. I just remove the stock fan and radiator- (i measure the area where the radiator is carefully to see what the biggest radiator i can find that will fit in there. Then i take the radiator to my radiator man and he trades me my stock, smaller radiator for a bigger one- or in some applications- he adds a new radiator core the radiator i have for added cooling)

With the stock fan, fan shroud, and radiator removed, you'll have a lot of room to work on other components of the engine. Got about 80,000 miles on your trailvoy?? Good time to get a new water pump. Get a high performance pump if one is available by checking with www.summitracing.com Change your engine drive belt now, if needed, and notice how easy that is to do.

Now mount your flex a lite "black majic" fan (this is the model i would use on a trailvoy) to your radiator, and then reinstall the assembly back in your trailvoy. If you got a bigger radiator, you may need to move a wire or two, or etc., to squeeze in the bigger radiator. Now notice how much more room there is to work on your vehicle without that fan shroud/fan in the way. Your water pump will also last a lot longer without that heavy fan clutch hanging off of it. And your engine will warm up much quicker without the fan turning, cooling it off before it can warm up. And you'll get a little more power and a little better gas mileage without the fan being turned by the engine. Keep in mind- the electric fan will not increase your cooling unless your fan clutch is bad. If you have a bad fan clutch- the electric fan will cure that problem- and you will get much better cooling. If not - the electric will not increase your cooling capacity much- but still well worth it. I've been running my flex a lite black majic in my Ford Ranger for three years- and for 10 years in the previous vehicle - GMC S-15 - all with the SAME fan! That is one tough fan. I promise a fan clutch will not last that long.

Now - make a note of what water temp your trailvoy is running at- and run the a/c wide open, idle the engine 30 minutes like at a stop light, etc. If it goes over 180 degrees (or over 210 if you run a stock thermostat) then you need to go to the next step. You need an engine oil cooler- again, the best ones i have found are at www.summitracing.com You'll also need a flex a lite fan to go either in front or in back of your oil cooler. Just measure the front end of your trailvoy and get the biggest oil cooler that will fit. Make sure your oil cooler is 1.5" thick and with 5/8" tubes- believe me- i learned this the hard way. I wouldn't give anything for the cheap 3/4" thick oil cooler- it doesnt do anything. Get the biggest length X width that will fit, and 1.5" thick. Be sure to get the type of oil cooler with "barbed" ends so that you can cut the hose any length you like- do NOT get fittings for your oil cooler- again, practical experience shows me all they do is leak. With barbed fittings- i can cut the hose to any length i need and they never leak. Be sure to use the high pressure "fuel line" quality hose clamps, stainless steel- you can get them at any good quality auto parts store like advance, NASA, Pep Boys. And they arent that expensive.

Now your oil capacity will be increased, and esp if you are are also running 180 degree water temp- you'll notice your oil lasts a lot longer before it gets black. Oil change intervals are lengthened. Also- the cooler underhood environment means that it is easier for your a/c compressor to get cold. Which do you think is easier on your a/c- an underhood temp of 180 degrees- or a smoking hot 240 degrees??

I did all of the above modifications on several vehicles, most notably a 1996 Ford Ranger 4.0 V-6. Boy does that engine ever overheat stock! (240 is when i shut it down- it was still climbing) But now, (with a 5.0 V-8 radiator, big summitracing engine oil cooler with flex a lite fan, 160 stat, mechanical water temp gauge, and also two more fans in front of the a/c condensor- total of 4 electric fans) it runs 180 degrees water temp, never, ever pings on 87 octane pump gas, runs with much more pep.

Now, when i step out of the truck and the air temp is more than 100 degrees- my eyeglasses immediately frost right over! I'd do everyone of those modifications over again. It is simply a different truck.

Now i am sure people out there are not going to do all of those things- but thought it might help someone if they did one of them. Good luck and let me know how your projects go. Sorry for the long post.
I want you to go outside and take some pictures of the install, i was told it couldnt be done, i would like to see this setup with the flex fan.

[Wxman]

The 230 and 235 temps are typically during stop-and-go traffic. Here is my 'normal'.
Returning from work on a hot afternoon. Temp gauge rises to about one mark below 210 and hangs out there just like all winter, for about 15 minutes. After that first 15 minutes the temp begins rising to the 230 or 235 degree level, three or four marks beyond the 210 mark. It will then pretty much hang out there after that. Even 10+ miles of 65 on the highway does not bring it back down.
Service guys are baffled, say it looks like the temp is on a timer to increase after 15 minutes. [Apparently the fan is getting a signal to engage, but doesn't engage as much as it should.]
Truck is still in shop (since 30 Jun). They are now replacing the PCM.
Soooo, three fan clutches, a PCM update, a new thermostat with flush and flow check, a complete PCM reprogram and now a new PCM. GM told service it wasn't PCM problem, even though they can't figure it out, so local guys had been hesitant to replace. Local service thinks that is where the problem must be and are changing the PCM on their own. We will see.

Wxman

[tbmdsd]

I added some Water Wetter and it did seem to make a difference. Hard to believe a $7.00 of fluid might work but it did appear to be at least one increment/line lower than where it ususally is.:)

[Wxman]

I had Redline's Water Wetter in it before I ever took it in the first time. Service agrees the fan is not engaging as much as it should. They just can't pinpoint why and get it fixed.

Thanks

Wxman

[Dacomputernerd]

How much $$$Canadian is a bottle of Water Wetter? Do you have to drain some coolent to make room, or do you just pour it into the cooling system?

[jdb1937]

jdb1937 interesting reading. Others have wanted to go the electric fan route, only to find out their GMT360/370 won't run, because the computer did not sense the OEM fan. Also, don't know of a 160 degree thermostat available for the 4.2L engine. :m2:

Thats really too bad about the electric fan. You see, i dont currently own a (Buick Rainier is my fav version) of the GMT 360 (what is a GMT 370?)

But what would i do if i had one? I would be emailing Flex a Lite and see if they have a switch or whatever that will override the problem with the PCM and allow them to install the flex a lite fan. Flex a lite is a company similiar to K&N- they will work with owners trying to fix PCM codes and such. I remember that the Chevy Colorado threw a CEL when owners installed K&N FIPKs on their vehicles. And K&N researched the problem and sent all owners a new air tube, solving the problem.

But if i was one of those people who didnt want to bother with flex a lite and etc., and my vehicle was running ANYTHING above 210 degrees water temp, i would take it to the dealer (if it had a warranty) and, not getting satisfaction there- i would install the engine oil cooler (with fan), and install one or two fans in front of the a/c compressor. These mods shouldnt throw a CEL or shut down the system. Engine water temp above 210 degrees is a big problem and it should be dealt with. And it puts even more strain on your a/c system-- which is already under a lot of strain. After a year or two of this high pressure on your a/c- guess what happens to it. All of your freon leaks out and you dont have a/c anymore. :confused:

[jdb1937]

Two more questions i would like to answer:

a. On taking a photo of my installation: first, i dont currently own a Trailvoy (Buick Rainier is my fav version) so i cannot show you an installation on one. (Also, i am currently in Mosul, Iraq and all of vehicles are in Kansas City- so i couldnt take any photos for that reason, too!) However: i have done the following vehicles: 2000 Jeep Grand Cherokee, 1996 Ford Ranger, 1998 Jeep Wrangler, 1996 Geo Tracker, 1985 GMC S-15. No i do not still own all of those. But all of them ran 180 degrees water temp when i was done, none of them have a CEL on- and i have yet to blow a head gasket, ping, or need to use any fuel over 87 octane.

However, i recognize that newer stuff is going to cause more problems. So i cannot wait to get my hands on a Buick Rainier, start modifying it, and find out what happens!

Another person mentioned that finding a thermostat for these newer GM engines is hard. Well, i couldnt find a thermostat for my 4.0 engine Ford Ranger either. But it happens that there is a 160 stat for a 3.0 Ford V-6. I asked for one of those thermostats, and compared it with the 4.0 thermostat- and they were very close. What did i do- i bought the 3.0 thermostat, brought out the dremel tool- and now the 3.0 thermostat has been in my 4.0 Ranger for around 5 years or so and doing fine. So i would go to an Auto Parts place with the 4.2 thermostat and ask for a Chevy 350 160 stat: i guarantee they have one for a 350! And see if it fits- or could be ground down to fit. Get all the 160 stats they have and compare them.

If worse comes to worse, here is what you might need to do if you want to run 180 degree water temp: i ran one of my vehicles without the thermostat- and no CEL either. All you need to do is make sure you have a water temp gauge and just turn on the electric fan when the engine reaches 180 degrees water temp. The engine will still warm up good even without a thermostat- because there is an electric fan, not a mechanical one. The mechanical fan turns even when it shouldnt, and this keeps the engine from warming up. But again, not sure if this will work with a Trailvoy- since it may trip a CEL without a thermostat- i dont know, but again, i cannot wait to try and find out.

Some people will say the engine will overheat if you run it without a thermostat- since the water goes through the radiator too fast, and doesnt get a chance to cool. As i mentioned, i have run vehicles without the thermostat before and havent had that problem- but here is what you do if you run into it: make a restrictor plate to go where the thermostat was. A restrictor plate is just a piece of aluminum with a 1/4", or 3/8" or so hole drilled in the center of it. Now you have the restriction function of the thermostat, and your cooling capacity should go back to where it was stock.

[Envoy Fan]

Thats really too bad about the electric fan. You see, i dont currently own a (Buick Rainier is my fav version) of the GMT 360 (what is a GMT 370?)


GMT 370 = long wheel base TB, Envoy, Ascender made at Oklahoma City assembly plant.

[tbmdsd]

How much $$$Canadian is a bottle of Water Wetter? Do you have to drain some coolent to make room, or do you just pour it into the cooling system?
Maybe 10-11 dollars Can. and you just add it to your existing coolant. I waited til it was cold and removed some directly from the radiator to add the Water Wetter right into it. You could put it in the reservoir bit I wanted it right in the radiator.

[Dacomputernerd]

Thanks :D how much should i take out? The same volume of the WaterWetter? Would it be ok if i didnt take any out?

[envoy62]

My 2002 Envoy I6 never goes beyond 200 water temp, i have been driving recently some pretty long distances in texas and Arizona in 100 -104 F temps and the temperature is never going higher then the 200 mark. I keep allways an eye on it becasue down here in El Paso the temperatures are fairly high in the summer months and you can see plenty of vehicles stranded with overheating problems.
Also is it possible that there are different cooling system set ups, i believe i did saw once on a vehicle spec a heavy duty cooling option?

In one of the earlier posts by jdb1937 the options to modify the cooling system with cooler thermostats larger radiator etc were discussed, i'm not sure if thats really necessary. Typically the car companies test their vehicles for worst case ( i.e death valley) and i would expect my vehicle not to overheat under normal conditions. This type of mod makes in my opinion sense if you tow a lot in extreme weather conditions.

The system that Gm uses on the I6 with the hydraulic clutch is a cheap system (this is done to save money versus an electrical system). Such a sytem doesn;t belong on an engine like the I6.
As this system gets older very often the fan will not rotate when driving in a city with a lot of stop and go and the engine will overheat (had an experience in the past on a different vehicle that used the same system).

For this reason the an upgrade to an electrical sytem is programed for my vehicle in 1 or 2 years.

Regards

[tbmdsd]

My 2002 Envoy I6 never goes beyond 200 water temp, i have been driving recently some pretty long distances in texas and Arizona in 100 -104 F temps and the temperature is never going higher then the 200 mark. I keep allways an eye on it becasue down here in El Paso the temperatures are fairly high in the summer months and you can see plenty of vehicles stranded with overheating problems.
Also is it possible that there are different cooling system set ups, i believe i did saw once on a vehicle spec a heavy duty cooling option?

In one of the earlier posts by jdb1937 the options to modify the cooling system with cooler thermostats larger radiator etc were discussed, i'm not sure if thats really necessary. Typically the car companies test their vehicles for worst case ( i.e death valley) and i would expect my vehicle not to overheat under normal conditions. This type of mod makes in my opinion sense if you tow a lot in extreme weather conditions.
The system that Gm uses on the I6 with the hydraulic clutch is a cheap system (this is done to save money versus an electrical system). Such a sytem doesn;t belong on an engine like the I6.
As this system gets older very often the fan will not rotate when driving in a city with a lot of stop and go and the engine will overheat (had an experience in the past on a different vehicle that used the same system).

For this reason the an upgrade to an electrical sytem is programed for my vehicle in 1 or 2 years.

Regards

Yes but how many miles do you have? Mine ran great until the factory warranty ran out at 36,000 miles. Now I have 62,000 and it overheats. If yours doesn't overheat it is because you still have low miles. These things hit 50,000 miles and they fall apart and many a lot sooner. Glad yours runs great.

[jdb1937]

Yes but how many miles do you have? Mine ran great until the factory warranty ran out at 36,000 miles. Now I have 62,000 and it overheats. If yours doesn't overheat it is because you still have low miles. These things hit 50,000 miles and they fall apart and many a lot sooner. Glad yours runs great.
Yes, i have experienced too many vehicles that are marginal at best with their cooling systems. If you get 3 bugs splatter against the front of the a/c condensor- it is now compromised, same with the radiator. Radiator and condensor should be blown out gently with compressed air- i wonder how many folks do this??

And i think it is interesting how people bring up how efficient they believe stock cooling systems are and how much respect they have for the manufacturers. Some manufacturers and some engines actually do pretty well, IE: John Deere two cylinder tractors from 1923 to 1960 and jeep wrangler inline 4 and inline 6 cyl engines and others.

But i have found too many stock cooling systems woefully inadequate, and that is after all the bugs have been cleaned out, Ford's 4.0 V-6 Ranger is certainly one of them.

Even after modification it is only acceptable, not ideal, like the J.D.'s and the Jeeps.

[tbmdsd]

I cleaned all the bugs out of the radiator but it didn't make a difference

[bmm354]

The system that Gm uses on the I6 with the hydraulic clutch is a cheap system (this is done to save money versus an electrical system). Such a sytem doesn;t belong on an engine like the I6.

I completely agree...but it actually does have something better. It uses an electro-viscous fan clutch, which operates similar to a typical hydraulic clutch except that instead of engaging/disengaging via mechanical means it's done electronically. The EV clutch uses a computer-controlled solenoid to turn on and off, which is nice because it won't engage unless it really needs to. It also allows engagement when the A/C pressure is high, the trans temp is high, or some trouble codes are set--something the typical hydraulic clutch can't do. With the EV setup you get the air moving capability of an engine-driven fan with the benefits of an electric, computer-controlled fan.

Just goes to show they really pulled out all the stops with the I6. :D

More info:
http://www.gmtechlink.com/images/issues/arcv_pdf/7_02_e.pdf

[jdb1937]

Just goes to show they really pulled out all the stops with the I6. :D

More info:
http://www.gmtechlink.com/images/issues/arcv_pdf/7_02_e.pdf

Pulled out all the stops?? Well, true, this system is better than a viscous fan clutch. Not to disagree with you, but i dont think all the stops are pulled out here. Otherwise the engine would stay 210 degrees or less all of the time, no matter what you do. I dont think it asking too much that a vehicle like this one tow 6,000 lbs, run a/c wide open in 100 degree weather, and run 210 degree water temp. (or even less- some toyotas do even less- not that i would consider buying a toyota- i like inline 6s and no toyotas are inline 6)

Stock, it will not do it. John Deere and Jeep pulled out the stops. This isnt all of the stops. :cry:

[bmm354]

Don't worry about disagreeing...that's just a natural part of these forums. I was referring more to the overall design / high feature content of the 4.2. As in going w/ an I6 layout, developing the EV clutch rather than using a standard viscous clutch, using variable valve timing, electronic 'drive-by-wire' throttle, etc. Heck, the 4.2 has been on Wards' 10 Best Engines list since it came out. It's a welcome departure from old, reworked engines.

I'd agree cooling performance does leave something to be desired. Mine runs at 210 throughout the summer (maybe one notch higher on hot days) and dips a couple notches lower in the winter months. But on a handful of occasions the gauge has risen to about ~230 in hot, humid weather in traffic with the A/C on. This hasn't happened for more than minutes at a time, but it's unnerving. I would like to know exactly what temp. the computer is seeing, as the gauge I'm sure is not exactly aircraft precise. Had the cooling system flushed and filled last fall when I bought it, so this is with clean coolant and no gunk inside the system. I may try Water Wetter one of these days--I've only heard good things about it.

Also, there is a revised EV clutch out there that, along with a software upgrade, is supposed to help keep things cooler and improve A/C performance. The TSB even mentions that these two fixes should help temp gauge readings too. It's # 04-01-38-019A and can be read in this thread: http://forums.trailvoy.com/showthread.php?t=689

[Laloosh]

i've towed, i've been stuck in traffic, i went off roading, i took a 3 hour nonstop trough mountain roads, my temp guage is glued on 210

[envoy62]

Mine also doesn't goe over 200 / 210 and thats with air conditioning running all the time, temperatures down here are so high that you won't drive wo a.c. Even when crossing the border from Mexico into El Paso, traffic is just creeping or standing, sometimes take 1 to 1 1/2 hours, and the air temperature gauge shows 130 F outside ( 3 to 4 lines of cars all idling ). Even under this extreme condition the engine temp never goes beyond or is glued ( to use Laloosh's term) to the 200 mark.
Maybe as i mentioned earlier there are differences in the cooling systems for different areas. Maybe somebody on the forum with more insight could answer that question if there is a heavy duty cooling option. ( checked the website build your GMC Envoy but didn't find anything).

:)

[jdb1937]

Don't worry about disagreeing...that's just a natural part of these forums. I was referring more to the overall design / high feature content of the 4.2. As in going w/ an I6 layout, developing the EV clutch rather than using a standard viscous clutch, using variable valve timing, electronic 'drive-by-wire' throttle, etc. Heck, the 4.2 has been on Wards' 10 Best Engines list since it came out. It's a welcome departure from old, reworked engines.

I couldnt agree more with this quote. This inline 6 was a very bold move by GM and i love it. I've always been nuts about inline engines, soon hopefully all of the vehicles on my farm will have inline engines in them. (only my ranger pickup is a 4.0 V-6, and it pales in comparison to this engine) The VVT and throttle just make it even better. And i am confident that soon GM will probably add full intake and exhaust VVT, DFI, and hybrid. All this means is even more fuel economy and power to the (imho) industry leader in efficient, mid-size, reasonably easy to work on SUVs.

I would go with the updated TSB that you provided, and if it doesnt fix the cooling issue i wouldnt hesitate to modify it because even 5 degrees above 210 degrees is way too hot. I run all my vehicles 180 degrees and i am pretty confident i could figure out a way to do that with the trailvoy also.

[hyounis2000]

My 2002 Envoy I6 never goes beyond 200 water temp, i have been driving recently some pretty long distances in texas and Arizona in 100 -104 F temps and the temperature is never going higher then the 200 mark. I keep allways an eye on it becasue down here in El Paso the temperatures are fairly high in the summer months and you can see plenty of vehicles stranded with overheating problems.
Also is it possible that there are different cooling system set ups, i believe i did saw once on a vehicle spec a heavy duty cooling option?

In one of the earlier posts by jdb1937 the options to modify the cooling system with cooler thermostats larger radiator etc were discussed, i'm not sure if thats really necessary. Typically the car companies test their vehicles for worst case ( i.e death valley) and i would expect my vehicle not to overheat under normal conditions. This type of mod makes in my opinion sense if you tow a lot in extreme weather conditions.

The system that Gm uses on the I6 with the hydraulic clutch is a cheap system (this is done to save money versus an electrical system). Such a sytem doesn;t belong on an engine like the I6.
As this system gets older very often the fan will not rotate when driving in a city with a lot of stop and go and the engine will overheat (had an experience in the past on a different vehicle that used the same system).

For this reason the an upgrade to an electrical sytem is programed for my vehicle in 1 or 2 years.

Regards
Do you mean that the upgrade is programmed by GM ? Is this upgrade only for EV Only? or TB Also??

[jdb1937]

Do you mean that the upgrade is programmed by GM ? Is this upgrade only for EV Only? or TB Also??

I would suggest simply put a reliable, well known, name brand, mechanical water temperature gauge on any water cooled engine you have in the upper radiator hose (usually) and see for yourself how your particular engine performs. My experience has been, although i know manufacturers test in harsh conditions, that they are setting the vehicle up for THEIR benefit, not mine. And i want mine set up for my benefit, not theirs. (IE- the vehicle lasts 100,000 miles and then blows its head gasket, and you go back and buy another)

[drhinckley]

I wonder if the Trailblazers imported to the Middle EAst have larger radiators? Today it was 125 degrees fahrenheit in the shade so hard telling what it was in the open. On my way back towards Kuwait City from one of the out lying camps my Intake Air Temp was 120, Coolant temp at 225 and Trans Temp at 228 with A/C on at 85 MPH. Needless to say, I turned the A/C off, rolled my window down and slowed down to about 65 and the Coolant temp dropped to about 210 and the Trans temp went down to around 220. My TB came from the states (California) so it has US specs. I replace the thermostat this past weekend and replaced the coolant with DEX Cool. I'm waiting on my plug and play trans cooler from PCMforLess and a deep pan filter from TCI so I can put my new TCI deep oil pan on the tranny. Does anyone know about the radiators on the exports to the Middle East?:sadcry: