Low oil pressure at Idle and hot

Tiny
EDDY1991
  • MEMBER
  • 2007 GMC YUKON
  • 6.2L
  • V8
  • 4WD
  • AUTOMATIC
  • 160,000 MILES
Dear Experts,

I have the SUV listed above Denali. I noticed that my oil level gauge drops below 20. The truck is running fine with no lifter or any other engine noise when revving.
The oil pressure easily goes up to 40 while accelerating.

Help needed. Thanks in advance.
Wednesday, March 30th, 2022 AT 1:09 PM

13 Replies

Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
Let's start with checking to see if the oil pressure gauge is accurate.

To do that we need to follow the info attached below to check the pressure.

If this is accurate than the typical causes are a pump issue, increased tolerance in the bearings.

Here is a guide that talks more about this:

https://www.2carpros.com/articles/high-or-low-engine-oil-pressure

At this point we don't need to worry about it if there are no noises, but we need to start by checking this info and not wait for there to be a noise.

If the pressure is low, then we can add an additive to thicken the oil and that will help get the max life out of this. I would not use a thicker oil, just use an additive like Lucas Oil.

Let's run through this info and let me know what questions you have.

Thanks
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Thursday, March 31st, 2022 AT 4:48 PM
Tiny
EDDY1991
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  • 44 POSTS
I am thinking to clean the oil pressure switch and change the oil pressure filter screen because when I bought this car, the old oil was burned and thick maybe it causes gunk to cover up the screen.
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Friday, April 1st, 2022 AT 3:30 AM
Tiny
KASEKENNY
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Okay. That is a good idea. My only concern with that is that if the oil was thick then that is sludge. If the engine has sludge in it then that is due to lack of maintenance, and it is going to cause issues in the future.

The best thing is to keep the oil changed but we may need to remove the valve cover and make sure it is not caked up in the top of the head. That will restrict the oil and cause issues.
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Saturday, April 2nd, 2022 AT 8:31 AM
Tiny
EDDY1991
  • MEMBER
  • 44 POSTS
Thanks a lot mate. I will keep posting just need some time from work to relax and start the work.
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Saturday, April 2nd, 2022 AT 9:57 AM
Tiny
KASEKENNY
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Sounds great. Let us know what happens or if you need more help. We will be here whenever you get to it.

Thanks for the update.
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Saturday, April 2nd, 2022 AT 10:55 AM
Tiny
EDDY1991
  • MEMBER
  • 44 POSTS
Dear Kenny,

What kind of additive do you recommend and how it will be used?

Thanks
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Tuesday, April 5th, 2022 AT 1:18 PM
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
There are a ton out there, but I have used Lucas oil before and I like it.

Take a look at the picture below of what I am referring to. The way this works is you substitute this in for some of the oil in the engine. So read the bottle to see how much you need to use based on the amount of oil the engine uses.

Let me know what questions you have about this.
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Tuesday, April 5th, 2022 AT 5:01 PM
Tiny
EDDY1991
  • MEMBER
  • 44 POSTS
Dear Kenny,

At last, the oil pressure came to normal 20PSI at idle and 40 while driving. I bought the truck and changed the oil to synthetic 5w30 but as per the hot weather it keeps on dropping the pressure. As per your opinion, I searched for the Lucas but it was unavailable in the market, so I returned back to my 20W50 because most of the cars here are running on 20w50 after facing oil pressure problem with full synthetic oil. While discussing with my friend he also started facing the same with his Tahoe 2015 and then he switched to 20w50.
All good until now.

Thanks a lot for your reply.
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Friday, April 8th, 2022 AT 7:34 AM
Tiny
EDDY1991
  • MEMBER
  • 44 POSTS
Image.
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Friday, April 8th, 2022 AT 8:49 AM
Tiny
KASEKENNY
  • MECHANIC
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Okay. Thanks for the update. That is good that the pressure came up. I will suggest one last thing if you are going to run that oil, that you let the engine warm up for a few minutes before you start driving. Basically, you want the oil to be hot so that it thins out slightly. If not, then the oil will not circulate that well and you could do some damage to the bearings if you drive it when the oil is cold and thick.

Thanks again for letting us know and that you are back up and running.
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Friday, April 8th, 2022 AT 12:52 PM
Tiny
EDDY1991
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Well noted kenny. Thanks for all your suggestions.
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Friday, April 8th, 2022 AT 12:54 PM
Tiny
EDDY1991
  • MEMBER
  • 44 POSTS
By the way, here the temperature is almost 35C in the morning and 20C at night.
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Friday, April 8th, 2022 AT 12:54 PM
Tiny
KASEKENNY
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  • 18,907 POSTS
Oh. That is warm. Okay. So, the thicker oil is going to perform just fine. Thanks for that info and using 2CarPros. Talk to you next time.
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Saturday, April 9th, 2022 AT 6:58 AM

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