Oil pressure fluctuation
Thread Starter
Teching In
Joined: Nov 2015
Posts: 37
Likes: 1
From: Dundee, OR
Oil pressure fluctuation I am having a strange oil pressure issue that I am hoping I could get some advise on.
Background info: This is a swap into a 68 C10 SWB.
Engine block is a LM4(2004 trailblazer ext) that has been bored to 5.7(3.898). And an LS6 5308 cam installed. Also has a ported GM performance oil pump in it. Motor has less than 1500 miles on it. Basically everything was replaced except the cam bearings.
On cold startup I have excellent oil pressure 45psi at idle with a steady needle. And after the engine warms if I still have 20+psi at idle. These readings taken from the top of the block at the stock oil sender location with a mechanical guage. This is NOT the faulty sending unit issue that seems to plague the F bodies.
However, I will sometimes get a unsteady reading. Shown in this video.
Anybody have any suggestions?
Background info: This is a swap into a 68 C10 SWB.
Engine block is a LM4(2004 trailblazer ext) that has been bored to 5.7(3.898). And an LS6 5308 cam installed. Also has a ported GM performance oil pump in it. Motor has less than 1500 miles on it. Basically everything was replaced except the cam bearings.
On cold startup I have excellent oil pressure 45psi at idle with a steady needle. And after the engine warms if I still have 20+psi at idle. These readings taken from the top of the block at the stock oil sender location with a mechanical guage. This is NOT the faulty sending unit issue that seems to plague the F bodies.
However, I will sometimes get a unsteady reading. Shown in this video.
Anybody have any suggestions?
My oil pressure gauge reads the same way. Will hold steady at 40-45 on cold start and once warmed up, reads around 28-30 with the slight fluctuation that you show. New oil pump and OPSU and the issue remains.
Staging Lane
Joined: Sep 2004
Posts: 62
Likes: 0
From: Hampton Roads, VA
Your pressure values are lower than mine but I think yours still fall in the typical range. I have a 1999 LS1 with 200k and I use Valvoline 5W-30 full synthetic and mine is 55-60 at cold start-up and it stays at ~40 when hot regardless of rpm.
Launching!
Joined: Jan 2016
Posts: 224
Likes: 1
I have a 2000 WS6 and had cam, timing etc installed...Also installed was a new high pressure oil pump...my oil psi sucked after that...The new oil pump cratered and I had another stock pump installed at another shop...at start, im 40psi....oil psi will drop to 10-12 at red light and back to around 35 when driving, and that's with 20w-50....Before the cam and stuff I was at 45 cold, and 35+ all other times with 10w-30..
