My friend has a 99 Silverado with the LQ4 6.0 in it, and since we got it running again (after sitting for about two years), it's had quirky oil pressure. Initially, there was a LOT of lifter noise (the knocking/tapping was definately top end), and at idle the oil pressure would be low or even zero turning on the "Low oil pressure" light. Oil pressure would be fine above idle. Last week, it got a LOT of lifter noise on his way to work, and then oil pressure dropped to zero, and didn't come back. Supposedly, the older LQ4's are known to have problems with the oil pickup tube O-Ring at the pump. We got the oil pan off and the pickup tube out today, and while the O-Ring isn't torn, it's oddly mis-shaped a little and rather "dry rotted". Enough that it could have been sealing or might not have been. We're going to replace the O-Ring, but if that doesn't fix the problem, what else might it be? I'm thinking next possible culprit would be the oil pump. Spun bearing has been mentioned somewhere along the line, but I'd think that wouldn't result in the zero oil pressure reading and top-end noise. Thoughts or suggestions? We don't want to put a ton of money into it if we can help it though since the "plan" is to swap a D-Max/Allsion into it at some point when we find a doaner truck, unless we where to swap a LQ9 into it to be pulled and put away for an older 'Vette down the road.
Oil Pressure issue - Not Diesel
- Thread starter Cougar281
- Start date
I was just thinking they stated it had been sitting for awhile, 2yrs. If the truck wasn;t started periodically then it's not uncommon in a gasser to need a pump. that's been my experience,
but the Fern man would pull the engine an put a diesel in it. LOL
but the Fern man would pull the engine an put a diesel in it. LOL
That's the end plan
But in the mean time, we want to get it running as is.The thing is, the flaky oil pressure was a classic symptom of the oil pickup tube seal. At idle, it would be flaky, but pretty much anything over idle it was rock solid.
Well, We'll replace the seal, but the motor back together and see what we get. If still no oil pressure, we'll be pulling the motor and going from there.
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the orings on the oil pan to filter were also a problem on these engines. getting the pan to line up properly can be a pain.