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Low Oil Pressure

50K views 22 replies 14 participants last post by  deltex 
#1 ·
I have a 2006 GMC Envoy Denali with 55k miles. Recently my oil pressure sensor bottoms out to 0. The stop engine warning comes on. Stopping and restarting the engine resets the gauge for about 5 miles. At stops the gauge will bottom out again. There is no noise or change in performance when the gauge goes to zero. The oil has been run less than 4k miles and is not low. Connecting to diagnostic computer does not shed any light. I took it to the dealer. They claimed to not be able to reproduce the problem. It started three days ago and has happened everytime I drive the car. The dealer is doing a second test drive but in my experiences with them they are not very reliable on their diagnosis. Has anyone else seen this problem? If so what are some possible solutions and is there a trouble shooting process that does not cost an arm and a leg?

Side note: I am scheduled for a road trip this weekend. I am nervous about taking the car out of town. It is driving fine but I do not want to do any damage. Opinions?
 
#7 · (Edited)
I had the same problem with mine. It wasn't the oil pressure sensor, because I replaced it myself. Took it to the dealer and they had to remove the intake manifold and clean or replace some screen or filter just under the oil pressure sensor. Cost me almost $700. I wish I would have done it myself. I know I could have.*
 
#9 · (Edited)
oil pres. fluctuating

I have the same problem. Never shows anything below 40+ lbs while running but usually when you stop it does a sudden nosedive to zero, and I get a stop engine warning...slight speed up and it returns to normal..pressure SHOWS an impossibly quick drop...HOPE it is sending unit.
Whoops...I have the v-8...must have mis-struck the set up button.
 
#10 ·
Exactly what occurred with mine. I changed the sending unit, and the problem stopped. The sending unit was a bit of the problem to get to, but once it was changed, problem solved. The sending unit is on the top back portion of the motor, closest to the cab.

Easy fix.
 
#11 ·
Hoping for some good news

Hey everyone, I'm brand new to the site, just signed up this morning. I'm having a similar issue, except I have 102,000. I'm hearing a small knocking, that is there sometimes loud, and sometimes not at all. Give me some good news please guys. :x I just bought this Denali not even a month ago. Thanks much!
 
#12 ·
Oil Pressure Low - Stop Engine

Im been having this issue for about two months now, I have recently checked my codes with Bluetooth ELM327 and Torque App, i pulled code P0016, which i read was a camshaft timing or something like that, i also read that the code can be triggered by a bad Camshaft Position Sensor, and / or a Crankshaft Sensor, I replaced the Camshaft Position Sensor, have not had the low oil pressure light come on since then, but its only been 2 days, im also going to change out crankshaft sensor to be on the safe side, because since i changed the Camshaft position sensor, i have had an increase in performance

Will keep you updated if any changes occur:woot:
 
#13 ·
I have an 07 Envoy Denali & I am having the same problem- the oil pressure drops to zero & the "turn off engine light"turns on.The motor does not run rough or make any noises. I already replaced the oil pressure switch & its still doing the same thing. A mechanic told me that it can be the gauge , is this true ?? please help ..
 
#14 ·
low oil pressure

I have a 07 Envoy Denali , the oil pressure gauge goes to zero & the "turn engine off" light comes on. The motor does not knock, loose power or run rough.I have replaced the oil pressure switch & it still does it intermittently. A mechanic said it can be the oil pressure gauge might be going bad. Is this true ? Please help..
 
#15 ·
Im having the exact same problem. Only thing I joticed is that it only seems to do it after it warms up. And after it starts it only does it when come to a stop. If you rev the engine at stop lights to about 1400 rpms it will hold at 50psi on the guage. I have a major trip planned in a month that I tow a 3000lb trailer and need this fixed asap. What would you try first?
 
#18 ·
I hate to be the guy that ruins the oil pressure sending unit party, but... I bought my 07 Trailblazer in April and 2 weeks later the whole Stop Engine light problem reared its head. I guess I should have known something was up because it had a new wiring connector on the engine oil pressure sensor. I put a EOP sensor on and cleaned the screen. Thought I had fixed it for a couple days but it began doing the same thing.Then I did some research and found some articles about the pressure relief valve in the oil pump getting burred and sticking open, which sends your pressure back to the pan. Only fix is to replace the oil pump. If you have a 4 wheel drive, this is a 15 hour job. If you're very handy and have tools you might be able to sneak the pump out of the gap below the front timing cover without removing the oil pan. You'll find the biggest obstacle is removing and reinstalling the 1 retaining bolt that holds the pickup to the bottom of the pump.


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#20 ·
I have a 2006 with the same problem. Changed the oil sensor and the problem was gone, for about 2 months. Oil pressure goes to 0, stop engine indicator comes on, but the engine sounds good and runs well. The dealer wanted to pull the engine apart, but a mechanic that I trust suggested that the problem is often caused by a buildup of sludge on the top of the engine, which is the result of short distance driving. I drive about 1 mile to work, so the engine doesn't warm up, the condensation builds in the engine and it is not running long enough to clear it, so a sludge will develop on the high points of the engine. It has nothing to do with not changing your oil, or the type of oil you are using. I use a partial synthetic and change my oil every 3,000 miles. The bottom of the engine is clean, and it purrs like a kitten with 230,000km or 140,000 miles As it turns out, there is a filter screen, located under the oil sending unit, that you can fish out, without taking the top of the engine. There are a couple of options, you can clean it, or replace it, either will work. It is not an expensive part, but I found that there are not many that know about this screen filter, called the Valve Lifter Oil Filter. Unless you google it, just googling the problem will not bring it up. It is a pretty cheap fix unfortunately it is not a common occurrence considering the number of 5.3's there are on the road, it really doesn't happen very often. If your oil pressure indicator is reading 0 and you shut of the car and restart it and the pressure comes back again, chances are there is not a problem with your oil pump. It could be a clogged oil screen on the intake, likely not if you have been maintaining your engine with regular oil changes. If it reads 0 and there is no noise in the engine, you probably have oil pressure but it is being blocked from getting to the sensor by a blocked Valve Lifter Oil Filter accessible directly under the sending unit, and removable by taking out the sending unit. Try this first before you start to pull your engine apart. You will know if that is the problem when you take it out and it is all gummed up. Clean it, put it back in, and keep an eye on your oil pressure guage. Chances are, the oil pressure will read higher than it has for a long time. You are going to have one of those ah ha moments when you see the pressure over 30 pounds on the guage and then remember that is where you remember it being when your car was new.
 
#21 ·
Keeping fingers crossed

I've wanted a newer GMC Envoy Denali for a couple of years and have visiting this site and doing much research on the pros and cons of the various Envoy options. My mechanic told me the 5.3 was the way to go. I bought a 2008 Denali with about 83,000 miles a couple of weeks ago.

Last weekend I was cruising at 70 and the oil pressure gauge went to 0 and the "Low Oil Pressure - Stop Engine Now" warning came up. I pulled to the berm and shut down. After I choked, bashed my head twice against the dash and told myself I made a stupid mistake buying someone else's problem vehicle, I checked the oil. The level was good, it was normal temp odor. I restarted and the pressure went back up to normal.

I immediately drove to a Chevy dealer where the service tech told me he had heard about similar issues with 5.3s in pickups and said it was possibly the pressure sensor/sender nd about a $400 job to replace it. He told me it would be OK to drive home but to keep an eye on the gauge.

Yesterday, I took the Denali to my trusted mechanic. I explained the issues and he looked up the symptoms on some sort of online "How to Fix it" service they subscribe to. This site shows symptoms and the fixes that subscribing mechanics have done to solve the problems. The vehicle-specific search pulled up over 150 similar reports in the system complete with error codes. There were probably over 130 fixes listed for this issue that listed replacing the oil pressure sender/sensor PLUS filter. The remaining fixes were replacement of ONLY the sender/sensor and NOT the filter, and a few that included replacement of the oil pump and/or pickup screen.

My mechanic replaced the sender/sensor (#12616646 $95) and filter (#12585328 $7). He said that he found metal shavings and gunk in the filter.

He did this all for under $200 without removing the intake manifold. He did mention that the GM flat rate for this is over $400 and does instruct the mechanic to remove the intake manifold.

So far it seems the problem is solved, and the bruises on my forehead are fading. For now I feel a bit better about my "new" Denail. I will update if the problem returns.

I love this forum and I'm sure I'll be using it for additional information and fixes!
 
#22 ·
Update - TomKatOhio

Since the oil pressure sender/filter change, I did an oil and oil filter change. Didn't notice any particles in the drain pan. Switched to Mobil 1 full synthetic. Pressure is registering over 40psi. I did a couple of 30 mile runs on the freeway at 80 with a couple of pretty hard accelerations. So far so good. Making a 4-hour trip this weekend. Still holding my breath.
 
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