Question about 2003 GMC Envoy

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2003 GMC Envoy - High Oil Pressure Reading

My oil pressure gauge is reading WAY beyond the high mard, it is as if someone has rotated the needle clock wise by 90°...where do I start in trouble shooting this, I have asked the dealer and they simply shrug their shoulders & say there is nothing they can do unless the service engine lite come on & produces an error code.

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  • afisher_80 May 24, 2009


    After finally looking into this last night I believe the diagram you had sent me was not for the 4.2L..I have removed the skid plate for a better view of the bottom end & cannot locate the sensor, I will take a second look this morning but it does infact look like a different block.

  • afisher_80 May 25, 2009

    Perfect, thanks Greg the sensor is now changed...but the problem still exists. Now where to look, is it possible that the problem is in the instrument cluster - faulty gauge? This vehicle definitely has some electrical issues, the service ABS lights also come on, but only when it is cold out (-5 and below), every time the temperature drops it never fails the light & chimes are going off. I have taken it to the dealer for this as well & the best they could tell be was to check the ground on the ABS Module located on the frame below the driver seat. Having said all this as far as the brakes go, the ABS still function 100% even while this warning light is on.

    Anyone having any similar issues please comment.




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Sounds like an oil pressure sensor. Here is a diagram to locate it for removal. Best of luck.

Posted on May 18, 2009

  • Greg Margossian
    Greg Margossian May 25, 2009

    Sorry, didn't know the engine size. This diagram (figure #4) should be more of assistance. All the best!


  • Greg Margossian
    Greg Margossian May 25, 2009

    There's a tester for checking actual oil pressure. Before investing in more expensive parts (i.e. oil pump) or tearing apart your dashboard, you may want to check the actual pressure to see if it's really high or showing a false high. If it checks out normal, it would seem everyone has an opinion on this issue. Some have suggested running thinner oil, some recommend changing out the oil guage in the cluster, and some have chosen to ignore it all together figuring high oil pressure beats low oil pressure. Hope this gives you a few ideas on how to cope with this issue. Best of luck.




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Has 358000 miles, just had leaks repaired. Twice since my oil pressure gauge reads no pressure but not all the time? Why

1. Oil Pressure Gauge Not Working You will notice this happens when your oil pressure gauge is not reading, whether the engine is turned off, idle or running. Try to step on the gas to rev up the engine. If the oil pressure gauge still doesn't change its reading, your gauge is busted. It's best to replace it as soon as possible because you won't have any idea if your car is already overheating or not.
2. Oil Pressure Gauge Reading Too Low When your engine is idle, the oil pressure gauge will have a low reading. When the engine starts running or when you're already cruising or on the freeway, your gauge's reading should have increased. If it stays on a low reading, then you now your oil pressure gauge is broken.
3. Oil Pressure Gauge Reading Too High Another common oil pressure gauge problem is when your oil pressure gauge is reading too high when your engine is idle or when it's turned off. Rep

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Oil pressure gauge reads 78

not all cars read the same,when the engines come down the assembly line they can vary from 15lbs ,just about enough to make the oil pressure light go out to anything up to 70lbs ,this depends on the clearances withing the engine so a decent oil pump and low tolerances can give this reading where as a engine with sloppy clearances will be low so ignore the pundits and bar room mechanics and leave well alone

Sep 28, 2012 | 2003 GMC Envoy

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Oil gauge on a 2003 gmc sierra is reading beyond 80, its all the way down. could it be serious? Just had oil change last week.

I'm assuming that this reading is at idle? The range for oil pressure is more like 30-40PSI at idle and 10-20 more at speed. The reasons your pressure is reading too high could be:

--The gauge or the sensor itself is bad (not uncommon)
--The mechanic used the wrong oil viscosity when changing your oil, and the thicker oil than specifications call for is causing higher pressures.
--The mechanic accidentally knocked off the wire to the oil sensor when changing the oil
--A bypass valve in the pump or filter is clogged and causing the high pressure.

This is a relatively new car and if this problem developed immediately after the oil change I'd suspect the wrong oil was used or the wire to the sensor was knocked off. If the problem developed near the oil change, but not right after, I'd suspect it was coincidence and that there is a problem with the gauge. Go back to your mechanic.

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How do I check and possibly replace the engine oil pressure sensor in a 2006 GMC Envoy Denali?

Oil Pressure Test Check for proper oil pressure at the sending unit passage with an externally mounted mechanical oil pressure gauge. A tachometer may also be needed, as some specifications may require running the engine at a specific RPM.
  1. While the engine is cold, locate and remove the oil pressure sending unit.
  2. Following the manufacturer's instructions, connect a mechanical oil pressure gauge and, if necessary, a tachometer to the engine.
  3. Start the engine and allow it to idle.
  4. Note and record the oil pressure reading when the engine is cold. The engine may need to run at a specified RPM, if so check the vehicle's specification.
  5. Run the engine until normal operating temperature is reached.
  6. Check the oil pressure reading again with the engine hot and record the value. Turn off the engine.
Compare the hot oil pressure reading to the specification. If the reading is low, check the cold pressure reading against the specification. If the cold pressure is well above the specification, and the hot reading was lower than the specification, the engine may have the wrong viscosity oil. Change the oil, making sure to use the proper grade and quantity, and then repeat the test.
Low oil pressure readings could be attributed to internal component wear, pump related problems, a low oil level, or oil viscosity that is too low. High oil pressure readings could be caused by an overfilled crankcase, too high of an oil viscosity or a faulty pressure relief valve.

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When throtling and transmission is shifting low oil pressure stop engine appears across the message center

The engine oil pressure need to be tested with a manual gauge hooked up to the engine to get an actual oil pressure reading.

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2004 envoy sounds as if it has no oil. no oil lights are on though. where should the oil pressure gauge be ? the need is in the middle. It sounds as if it is riding hard. I remember a car I had that...

The Envoy's oil pressure gauge is not showing actual oil pressure, the computer calculates the reading based on engine RPM and the on or off signal from the oil pressure switch. You need to first check the oil level on the dipstick, than have a mechanic put a manual oil pressure gauge on the engine to read the actual oil pressure.

Sep 25, 2010 | 2003 GMC Envoy

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The oil pressure guage doesn't move at all. The needle just sits all the way to the left. I have checked the oil level and its at full. I am just not getting any reading indication from gauge.

Well, stop using the vehicle...What if you actually had zero pressure??

If, however, you are hearing nothing unusual from the engine, you may actually have pressure, but no indication.

Test with a pressure gauge. If you do not have one, just replace the pressure sender. It takes a SPECIAL socket, so locate and borrow or buy one.

The pressure sensor is a high failure item, generally.

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03 gmc envoy with 5.3 140000 miles. Oil pressure reading fluxuates between 0 and 40. When problem first started pressure read 80. When vehicle was new it stayed at midpoint (40) vehicle has plenty of oil....

There may be a loose wire or the gauge or sending unit may be going bad. The first thing I would do is to hook up a temporary oil pressure gauge, not using the old one at all. With this watch gauge while driving and see what readings you get. If the readings still jump around you have a pump that is getting weak and failing, If that is the case the pump should be replaced, but with high milage you may consider rebuilding the entire engine. If the readings stay normal start checking for a loose wire at gauge or sender. Then check sender, then gauge and replace as needed.

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Oil pressure reading in 2003 gmc envoy

No problem with the oil pressure, the norm is between 40 to 60. Anything lower then 40 you have low oil pressure and anything above 60 then you have high oil pressure which is caused by a blockage in the system.
What is common is the oil pressure gage fluctuating for the first 200 miles if the oil pressure sending unit is getting worn. Good maintenance will keep the engine clean and running good but the oil pressure sending unit is inexpensive and easy to replace. Next time you do an oil change you can have them change the sending unit.
Good luck and hope this helps. You can pick up the sending unit at Auto Zone and most auto parts store and will have the step by step to replacing it. If you do attempt to replace it. make sure you DO NOT USE any Teflon tape or silicon on the threads, they are tapered and need a good ground to the engine for proper readings.

May 28, 2009 | 2004 GMC Envoy

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