GM 98 up V8's low oil pressure, slow to build

[jkhawaii]

it seems like it's a fairly common issue but, its the first time I have seen it.
2009 GMC Sierra, 5.3, with 167,000 miles (lots of long drives) engine has very very low oil pressure that occurs most when cold not hot. oil pressure confirmed low at the filter mounting and at the sender, shows 2psi in drive when engine is cold. seemed to be a oil pump concern, sold oil pump and related. when removing the oil pump pick up I thought it was odd that the pick up did not seem to have any resistance being removed from the pump and, the o-ring did not seem to make contact and, was no longer round. the oil pump was also a bit worn out but, the main issue I believe was the pick up o-ring. with the new oil pump and pick up o-ring oil pressure builds rapidly and is well over 50psi at idle cold.

 

[SteveSRT8]

Originally Posted By: jkhawaii
it seems like it's a fairly common issue but, its the first time I have seen it.
2009 GMC Sierra, 5.3, with 167,000 miles (lots of long drives) engine has very very low oil pressure that occurs most when cold not hot. oil pressure confirmed low at the filter mounting and at the sender, shows 2psi in drive when engine is cold. seemed to be a oil pump concern, sold oil pump and related. when removing the oil pump pick up I thought it was odd that the pick up did not seem to have any resistance being removed from the pump and, the o-ring did not seem to make contact and, was no longer round. the oil pump was also a bit worn out but, the main issue I believe was the pick up o-ring. with the new oil pump and pick up o-ring oil pressure builds rapidly and is well over 50psi at idle cold.


Beg your pardon, but the factory GM PCM will pull spark at around 4-6 psi and the engine will not run.

 

[ls1mike]

Originally Posted By: SteveSRT8
Originally Posted By: jkhawaii
it seems like it's a fairly common issue but, its the first time I have seen it.
2009 GMC Sierra, 5.3, with 167,000 miles (lots of long drives) engine has very very low oil pressure that occurs most when cold not hot. oil pressure confirmed low at the filter mounting and at the sender, shows 2psi in drive when engine is cold. seemed to be a oil pump concern, sold oil pump and related. when removing the oil pump pick up I thought it was odd that the pick up did not seem to have any resistance being removed from the pump and, the o-ring did not seem to make contact and, was no longer round. the oil pump was also a bit worn out but, the main issue I believe was the pick up o-ring. with the new oil pump and pick up o-ring oil pressure builds rapidly and is well over 50psi at idle cold.


Beg your pardon, but the factory GM PCM will pull spark at around 4-6 psi and the engine will not run.

This...It is program for all LSx motors.

 

[NHGUY]

Reminds me of the Vega,with low oil pressure shut down of the electric fuel pump.They could have gone with a mechanical pump,but probably did that because they knew they were serious oil burners.They made it look like an engineering advance though,an electric pump.

 

[229]

That pickup tube O-ring is a common failure item.

 

[jkhawaii]

Steve, a shut engine off message did display on the DIC, but, the engine did not shut down.

 

[jkhawaii]

I can imagine putting thicker oil to try to fix this condition would make things worse being the pick up tube o ring is the issue.

 

[heynow]

It's a shame when a mfg cheaping out on a 50 cent o-ring costs people engines.

 

[Trav]

Originally Posted By: NHGUY
Reminds me of the Vega,with low oil pressure shut down of the electric fuel pump.They could have gone with a mechanical pump,but probably did that because they knew they were serious oil burners.They made it look like an engineering advance though,an electric pump.

The first car i ever saw with this system was a 69 Riviera. GM was nice enough to put a glass fuse in a separate holder under the brake booster and forgot to tell anyone.
It sure made for a fun repair.

 

[antonmnster]

A prior Volvo 850 had a loud lifter tick when cold. When doing the timing belt once I, for some reason, pulled the oil pump off the crank and noticed that the gasket behind it was in poor condition.

I replaced the gasket and the lifter tick was totally gone.

Don't overlook the simple things.