Yet another Yukon with engine tick and low oil pressure

[donjetman]

Thanks again everyone.

That pump extractor looks great, I will get one, thanks.

I bought a scanner and hooked it up when the engine was warm and at idle, oil pressure fluctuated around 11.9 and 13.9 - so it is lower than what I’d like to see.

Is this with the extra 2 qts and parked nose down?

 

[YukonDK]

Is this with the extra 2 qts and parked nose down?

No I haven’t done the 2 extra qts yet, I’ll need that extractor pump so I can get the extra qts out again. This was just out of curiosity as to what oil pressure was when engine was warm and at idle as I bought the scanner and wanted to test it. But when I do the extra qts and nose down, I will hook up the scanner again and see what it reads.

 

[Meathead16]

No I haven’t done the 2 extra qts yet, I’ll need that extractor pump so I can get the extra qts out again. This was just out of curiosity as to what oil pressure was when engine was warm and at idle as I bought the scanner and wanted to test it. But when I do the extra qts and nose down, I will hook up the scanner again and see what it reads.

Any update on this?

 

[YukonDK]

Any update on this?

Not really, unfortunately.

I couldn’t find the ‘extractor’ so I decided that I would have the shop replace the o-ring. They will be replacing the o-ring mid April.

Symptoms still the same. However, as temperatures haven risen since it’s spring, the ticking/knocking gets quiet way faster than when it was winter.

Took the family on a 500 mile trip a couple of weeks ago. The Yukon was an absolute pleasure to drive. Driving at approximately 1800 rpm, oil pressure was steady at 40 psi. At idle still 11, when engine is warm.

Did get the exhaust manifold clamp installed, but that didn’t do the trick - tick/knock is still there at start up.

I will update once the o-ring has been replaced.

 

[YukonDK]

Update.

Got the Yukon back after the o-ring replacement.

Oil pressure is worse now than before the change. Before the change it was 11 psi at hot idle, now it’s 8 psi.
Oil and filter was also changed so everything should be new. However I never thought that the pressure would get worse after the change, it really sucks…

 

[BlaineBug]

Update.

Got the Yukon back after the o-ring replacement.

Oil pressure is worse now than before the change. Before the change it was 11 psi at hot idle, now it’s 8 psi.
Oil and filter was also changed so everything should be new. However I never thought that the pressure would get worse after the change, it really sucks…

That makes no sense. What else did they say? Did they inspect the pickup tube and screen, did they clean it out thoroughly? Making the seal refreshed and rejuvenated yet resulting in lower pressure doesn't add up IF no other factors changed.

 

[j91z28d1]

I mean 3 psi is a pretty small difference. especially if read off the dash gauge, could be just a different brand oil filter or a few rpm lower idle.

I'd chalk that up as no change in my book. I do personally believe we overly blame the o'rings for low oil pressure, from posts I see most end up going back in with a high volume pump. Sadly that might be your next step. if it's something you can do yourself, I don't know.

 

[PatDTN]

I'm fairly sure there were 3 different o-rings to choose from when I went through my junkyard 6.2 before I installed it. The existing was in tatters but I bought the same color.

 

[PatDTN]

Oh and my oil pressure rarely gets below 40 since I blocked off the AFM oil galleries.

 

[YukonDK]

That makes no sense. What else did they say? Did they inspect the pickup tube and screen, did they clean it out thoroughly? Making the seal refreshed and rejuvenated yet resulting in lower pressure doesn't add up IF no other factors changed.

They said that the o-ring was flat and hard. Didn’t mention anything about pick-up screen, I think they only changed the o-ring. They did put on a new oil pan gasket, 5w30 oil and AC Delco oil filter. At this point I can’t find a reasonable explanation for having a worn out o ring replaced and then have lower oil pressure. Even on cold starts it’s a tiny bit lower (picture in post). For now it’s an unsolved mystery