Somewhat Fixed ! Low Oil Pressure at Low Idle !

[YD2007]

(I wish one could change the title of a previous post, because I don't like creating another thread. I'm the same person who posted "Low Oil Pressure When Warm, Engine Shuts Off When < 10" )

I convinced the fixit guy to check/change the oil pump pickup tube O-Ring, based on many posts here that said "Changing O-Ring fixed my low oil pressure)...if it looked ok, then we'd go with a Jasper 3 yr/100K mi - warranted rebuilt ($7700).

The O-Ring (picture included) did indeed have a split in it.

Now, instead of warm idle being around 5 or on the low red mark, it's around 12-15. Should be higher, but that'll keep the engine from quitting, and that fix, with ~$100 labor investigating, plus $600 for changing O-Ring, beats $7700.

They also replaced the rear engine main seal - was leaking.

The advantage of going with thee rebuilt engine, is the Yukon would be a little easier to sell/trade in another year...wwe'll see what another year brings.

Dave H.

 

[MichaelSE]

Glad to hear it. Some mechanic once told me that replacing the oil pan gasket (or oil pickup o-ring for that matter, same process) on a 4x4/AWD 5.3/6.0/6.2 is rated at something insane like 12 hours of labor. So sounds like you got a good deal with $600.

Switch to high mileage rated synthetic oil if you haven't already.

 

[iamdub]

Cleaned the screen behind the oil pressure sensor? That being partially clogged will make the sensor read low.

 

[Jagsta]

I just did this and it fixed my low/no oil pressure at cold idle. LOL at a pro quoting 12 hours labor, it took me prob 8 but I was being slow and meticulous, no way a pro with a lift who works on cars day in and out takes 12 hours. Hardest part was maneuvering the front differential out of it's small space. You def need a small transmission jack to get it back in (I was able to remove with a regular jack and roping the diff off to the frame, ended up finding my old small Harbor Freight tranny jack later and using it on the re-install.). I took pictures and will make a guide available sometime soon, it's really pretty easy overall.

 

[JonnyTahoe]

You have to move the Differential on a 4X4 just to drop the pan ?

 

[HiHoeSilver]

You have to move the Differential on a 4X4 just to drop the pan ?

Sure do.

 

[JonnyTahoe]

I just did this and it fixed my low/no oil pressure at cold idle. LOL at a pro quoting 12 hours labor, it took me prob 8 but I was being slow and meticulous, no way a pro with a lift who works on cars day in and out takes 12 hours. Hardest part was maneuvering the front differential out of it's small space. You def need a small transmission jack to get it back in (I was able to remove with a regular jack and roping the diff off to the frame, ended up finding my old small Harbor Freight tranny jack later and using it on the re-install.). I took pictures and will make a guide available sometime soon, it's really pretty easy overall.

Looking forward to the pictures. I assume you used air tools, Impact wrenches, and you were able to do this on the Garage Floor with nothing more than floor jacks ?

 

[JonnyTahoe]

Sure do.

I just began the oil pan removal today.

 

[HiHoeSilver]

well that's not going to happen in my garage.

 

[JonnyTahoe]

Cleaned the screen behind the oil pressure sensor? That being partially clogged will make the sensor read low.

 

[HiHoeSilver]

Where is this sensor located ?

At the back of the block on the top.

 

[iamdub]

Where is this sensor located ?

Top of the engine, at the back, behind the intake manifold. It's a pain (literally) to reach, but can be done without removing the IM. If you've never cleaned and sealed the knock sensors (assuming that's your rig in your avatar), you may wanna remove your manifold to do this and check and/or replace the oil pressure sensor and/or screen while you're at it.


Here's a pic of an LS engine in an F-body, but that's irrelevant. The intake manifold is removed and you can see the oil pressure sensor in the red square. The knock sensors are just in front of that in the valley cover under the two black circles with the wires going to them.

 

[JonnyTahoe]

Top of the engine, at the back, behind the intake manifold. It's a pain (literally) to reach, but can be done without removing the IM. If you've never cleaned and sealed the knock sensors (assuming that's your rig in your avatar), you may wanna remove your manifold to do this and check and/or replace the oil pressure sensor and/or screen while you're at it.


Here's a pic of an LS engine in an F-body, but that's irrelevant. The intake manifold is removed and you can see the oil pressure sensor in the red square. The knock sensors are just in front of that in the valley cover under the two black circles with the wires going to them.

Thanks Chris. Yes its the truck in the pic. I have noticed it before but never realized it contained a screen. Never had the Intake off but have removed the foam that comes from the factory in the front. I hear there is another in the rear. I will give it a shot with the Intake on and see how it goes. As long as its off I think I will replace it with a new one.

 

[iamdub]

Thanks Chris. Yes its the truck in the pic. I have noticed it before but never realized it contained a screen. Never had the Intake off but have removed the foam that comes from the factory in the front. I hear there is another in the rear. I will give it a shot with the Intake on and see how it goes. As long as its off I think I will replace it with a new one.

That foam helps to keep debris and water from getting under the IM and working it's way under the knock sensor seals and building up around them. It's a well-known issue and the fix is to remove the IM, pop off the wires and seals, vacuum out the water and/or debris, replace the knock sensors, and reassemble but with adding RTV sealant to those knock sensor harness seals. It's a good time to clean the oil and sludge out of the IM, too.

 

[HiHoeSilver]

Here's how you get at it.

 

[JonnyTahoe]

Here's how you get at it.

View attachment 181714


View attachment 181713

Thanks for the pics. I do have those exact tools and even blasted the back of the motor last summer to make changing that sensor a cleaner job.

 

[S_wall98]

I just did this and it fixed my low/no oil pressure at cold idle. LOL at a pro quoting 12 hours labor, it took me prob 8 but I was being slow and meticulous, no way a pro with a lift who works on cars day in and out takes 12 hours. Hardest part was maneuvering the front differential out of it's small space. You def need a small transmission jack to get it back in (I was able to remove with a regular jack and roping the diff off to the frame, ended up finding my old small Harbor Freight tranny jack later and using it on the re-install.). I took pictures and will make a guide available sometime soon, it's really pretty easy overall.

Looks like I'm bringing this one back from the grave.
Jagsta, did you ever get that guide made?