Does Synthetic oil REALLY help? [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Does Synthetic oil REALLY help?


agates1272
07-31-2007, 12:48 PM
Hi all, new member here. I made a couple of posts on the sticky regarding the "diesel" engine noise I hear at startup on my 05 Envoy. Taken it to the dealer, and of course, they say it's "normal", and there's nothing they can do.

I've seen a few posts from folks who started using full synthetic oil---does it really quiet it down? It's embarrasing to start this thing up in the mornings. It's not that bad at idle, but man, when I shift into gear and put the engine under load, it's rediculous.

If it does help, what's the best synthetic to use??

Thanks guys!

Adam :o:o:o:o:o

KNBlazer
07-31-2007, 12:50 PM
that diesel sound I keep hearing about ... is it a roar? if it's a roar that is your fan clutch ... I don't hear it on my TB .. I do however hear the fan clutch roaring as if you had blown your tranny and the engine is just roaring...

justblazin
07-31-2007, 12:55 PM
MY Rainier is a bit noisy on startup, but after about 5 minutes of driving she is nice and quiet. I use Synthetic blend in my truck, usually mobil 1.

I can say my friend has run syntehtic in his 1999 Sierra since new. It has 150000 miles on it and it still as strong as day 1. He is still on the original drivetrain with no failures except he had to replace his rear diff at 135000

agates1272
07-31-2007, 01:05 PM
that diesel sound I keep hearing about ... is it a roar? if it's a roar that is your fan clutch ... I don't hear it on my TB .. I do however hear the fan clutch roaring as if you had blown your tranny and the engine is just roaring...

No, it's not a roar. After finding this site, I went out and started it up. the noise is definately from the block, and not the fan. Fan clutch look sfarily new, so I'm assuming it had already been replaced prior to my purchasing it.

Knightslugger
08-01-2007, 05:37 PM
All of GMs I6 motors sound a little like a diesel.

MAY03LT
08-01-2007, 06:49 PM
Fan clutch look sfarily new, so I'm assuming it had already been replaced prior to my purchasing it.

Mechanics code 3115 Never assume anything.....

I use Mobil 1 and the engine sounds the same as the day I bought it.:m2:

RayVoy
08-01-2007, 07:38 PM
No, it's not a roar. After finding this site, I went out and started it up. the noise is definately from the block, and not the fan. Fan clutch look sfarily new, so I'm assuming it had already been replaced prior to my purchasing it.If indeed, it is an internal problem, synthetic oil WILL NOT fix it. If anything, it will probably make it sound worse (less friction, may increase the noise). But, the good news is, if the problem is (as GM said) nothing to worry about, then the lower resistance may keep the problem from getting worse. Usually cold start up noise will be from piston slap (piston loose in the bore) when the metal warms and expands the noise goes away.
A lot of other things can cause noise at start and a lot of them will get worse when the engine warms, these are things that u probably need to worry about. But if urs goes away when warm we can save those for an other thread.

longspur
08-01-2007, 09:52 PM
Hi all, new member here. I made a couple of posts on the sticky regarding the "diesel" engine noise I hear at startup on my 05 Envoy. Taken it to the dealer, and of course, they say it's "normal", and there's nothing they can do.

I've seen a few posts from folks who started using full synthetic oil---does it really quiet it down? It's embarrasing to start this thing up in the mornings. It's not that bad at idle, but man, when I shift into gear and put the engine under load, it's rediculous.

If it does help, what's the best synthetic to use??

Thanks guys!

Adam :o:o:o:o:o

I have something in common with you. I have the 05 Envoy with 26,000 miles and mine sounds the same way.

I feel it is completely normal. My 04 Montana van with a 3.4 has always done this as did the previous one and most of the other vehicles I have owned as well. I will have mine in next tues. for some warranty work and I will ask them what they think.

If you keep up on reg. oil and filter changes I really do not think it will make a bit of difference. If you were racing or really pushing the load limit then syn. is the way to go.

This engine will outlast your use and then some kid will buy it and it will still be running 15 years from then using reg. oil. Dont worry.

Knightslugger
08-01-2007, 09:57 PM
If you were racing or really pushing the load limit...

or looking to lengthen your oil change interval...

then syn. is the way to go.

and i agree.:yes:

dpshook
08-01-2007, 09:59 PM
I love Royal Purple I put it in everything i own.

Even my John Deere Mowers!

TBlazeruss44
08-01-2007, 10:55 PM
or looking to lengthen your oil change interval...



and i agree.:yes:

OR....Really wicked cold weather starts!!!:yes::)

ssilicon
08-02-2007, 02:26 PM
Synthetic oil is SUPERIOR to regular oil , period. It is BETTER for engines. It will not likely quiet down your valve train noise. In fact, if you use regular oil you may more easily build up deposits on your valve train, which may make it more quiet. The big thing here is not to equate quietness with being the best for the engine. Clean , cool and well lubricated is what's best.

Engines are machines with moving parts. Moving parts make noise. How much noise varies but more noise does not always mean a problem or a bad design.

rouxzy
08-08-2007, 05:38 PM
First post here, but when it comes to oil the sysns are superior. I own an older Porsche and run nothing but Mobil1 for a couple of reasons. Synthetics take longer to break down. They tolerate heat much better than dino oils and they have better detergents in them to keep your engines free of deposits. The syntheics are also better in cold weather starts because they don't thicken up like conventional oils do. So, you don't have to wait for that cold thick oil to warm up to lubricate.
Tom

inphoenix
08-08-2007, 05:57 PM
Ten mechanics, ten different opinions. Change it regularly.

ejlib
08-08-2007, 07:43 PM
I swear by Mobil 1 Full Synethic Oil. It also extends the oil life so I don't have to change it so often as long as I use a long-life filter as well. I used to use the Fram Oil filters that were rated for up to 7,000 miles but now Mobil 1 started making the same kind of filter so I'm using those now.

02Bravado
08-11-2007, 03:31 AM
My I-6 does not sound like a diesel, quite honestly its extremely quiet and only noisy on start up when the fan decides to be engaged when the a/c is running at stat up.

I agree that synthetic oil should not cure internal engine noise but it has a few benefits that others have mentioned. I have been using Diesel grade synthetic oil as it is spec'd to pass GM's engine oil requirements for all grades of trucks and I can buy it buy the gallon and not have to pay as much for it as mobile 1. The other thing that I noticed on my 4cyl car when I switched to synthetic was that due to the reduced friction, my cruising rpms at 70mph was lower slightly and again slightly increase my mpg. This effect likely gets dimished as engines get larger but it was noticeable on my honda.

Synthetic is also superior from a property standpoint but for the above reasons are why I use it. As for the better for engine life, that will be a forever debate. I actually read consumer reports article that basically stated that synthetic and engine treatments had no effect on engine wear. My only thought on that is many OEM's spec synthetic for their engines so there must be something to it. I mean they would not spend the extra money without their being a benefit.

MtnManTB
08-11-2007, 04:55 AM
As was mentioned in an earlier post, everyone has a different opinion when it comes to Motor Oil. Is Synthetic superior? Yes. Especially in extreme driving conditions such as extremely low or extremely high temperatures. Is that extra level of protection worth it? Maybe. If you plan on keeping your vehicle for many years, it probably is. If you turn vehicles over every couple, definitely not. I remember that Consumer Reports Motor Oil study from a couple years back. They tested all the major motor oils in several taxi cab fleets - to provide a harsh, stop and go environment and to quickly accumulate the mileage level sought after for the test. Conclusion? The amount of wear on the cam was something like the weight of seven staples when comparing conventional to synthetic motor oil. Also, if you drive in an extremely dusty environment - such as we have here in the desert outside of Phoenix - you are better off changing a standard motor oil more frequently than using a more expensive synthetic under an extended oil drain maintenance plan. Usually, I use a heavier weight, 10W-30 synthetic, during our hot summers and a standard 5W-30 during the mild winters. The heavier synthetic provides better protection during the extreme temperatures of summer. I plan on keeping my TB forever, so, for me, the extra cost of using a synthetic at least part of the year is worth it. As a side note, when I was still at GM, several years ago, Powertrain had a 3800 Series II powered Pontiac Grand Prix in one of the shops at the Tech Center in Warren. The motor had seized up after 140,000 miles. Seems that a female customer had bought the vehicle new and driven it without ever changing the motor oil. She maintained the oil level - to be sure - by adding periodically, but never changed it. The techs tore it down and could not believe it had sustained that kind of abuse, but it did. That is a true tribute to GM motors!

:thumbsup:

bullethole
08-11-2007, 10:06 AM
From a different angle, I use the oil life monitor on my truck. It usually calls for a change at about 9000-10000 miles. That is why I use synthetic. I have a friend who rebuilds engines and he has shown me the difference in the oil pan between syn and dino on high mileage engines and that was enough to convince me to use syn. There will be some or a lot of sludge in the dino motor. The syn pans were almost new looking.
That being said, if you do not plan on keeping your truck until at least 200k it will not make much difference. Just change it according to schedule.

Super 88
08-11-2007, 02:06 PM
Usually, I use a heavier weight, 10W-30 synthetic, during our hot summers and a standard 5W-30 during the mild winters. The heavier synthetic provides better protection during the extreme temperatures of summer.


The synthetic oil may help provide better protection, but at operating temperature all 30W oils are basically the same. A 10W-30 is not "thicker" than a 5W-30 at operating temperature. The "W" does not stand for "weight" but "winter" or how well the oil flows at low temperatures.

This quote is from Valvoline's web site:
"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt. "
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040601ov&cccid=2&scccid=2

MtnManTB
08-25-2007, 01:51 PM
Super 88 - you are correct, at normal operating temperatures a 30 is a 30 is a 30. I was referring to start up - preferring a 10 weight over a 5 during those first few minutes until normal operating temperature is reached.

The synthetic oil may help provide better protection, but at operating temperature all 30W oils are basically the same. A 10W-30 is not "thicker" than a 5W-30 at operating temperature. The "W" does not stand for "weight" but "winter" or how well the oil flows at low temperatures.

This quote is from Valvoline's web site:
"SAE 30 is SAE 30 no matter what the "W" prefix number is: 0W, 5W or 10W. This viscosity in centistokes (cSt) @ 100 degrees C is with the minimum of 9.3 cSt and a maximum of 12.5 cSt. "
http://www.valvoline.com/carcare/articleviewer.asp?pg=ccr20040601ov&cccid=2&scccid=2