Oil Pressure Problem(Have Searched)
Oil Pressure Problem(Have Searched) I installed H/C(in Sig) about 5000 miles ago. I've recently noticed that there is a clacking type sound coming from the engine. At start up (cold) I have 65psi oil pressure and then slowly it will drop to around 30psi once the car starts warming up. At 2000 rpm I have about 50psi. Ive also noticed that my Oil Press. gauge is vibrating and flucuating at idle. I replaced the OPSU and the gauge still does it. I.ve been researching on here and I'm starting to lean towards the Oring being screwed up. I have the Melling 296 HV pump in it. I was extra careful when installing the oring and made sure not to screw it up. Does anyone have an opinion on what they think my problem may be? Any info would help out.
Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
30 psi at idle is plenty. I have had 2 LS1s in my car and both have had 30-32 psi at idle. 50 at 2k is plenty too....About the gauge vibrating, it could be slightly inaccurate or it could in fact be an o ring issue.
Thanks for the reply. I guess its just got me nervous. It seems like alot of peoples cars have way better oil pressure than mine. Especially since I have the the HV pump with High Pressure spring installed. I was leaning towards a bearing problem but I would think my pressure would be low all the time at all Rpms? Mines only low at idle..
Did you check it with a real gauge? If the factory dash gauge is bouncing around you probably have a bad sending unit. Check it with a real mechanical gauge to verify.
Or it could be bad spark plugs like the Fastvet said
WTF was that comment 
Or it could be bad spark plugs like the Fastvet said
WTF was that comment 
TECH Resident
Joined: Feb 2006
Posts: 855
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From: Omahaish. Nebraska.
Where do you hook up the mechanical gauge at? I kindof wonder about my oil pressure at times. Car's an auto and when I'm sitting at a light, i get around 25 psi warm. WOT hovers around 50..... hoping it isn't a motor problem
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Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
I just recently checked mine with a mechanical gauge. I broke my OPSU and replaced it with an Oriellys part. I installed the motor and noticed the pressure was down. I thought it was internal problem with the motor but after verifying it, I noticed the gauge was up to 10-15 psi off at idle and over 20 off at higher rpms. It seemed to only function in the 30-50 range. Not accurate at all.
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Brett Foote Joined: Aug 2007
Posts: 24,241
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From: Turnin' Wrenches Infractions: 005
I got a harbor freight oil pressure gauge with adapters and drilled and tapped the pressure port above the oil filter. It cost me about $25 and I had to buy the drill and tap.
i know it sounds farfetched but i had a similiar issue in which my oil pressure would drop to zero warm and constantly fluctuate but had decent pressure at driving and cold start. Believe it or not my oil pump bolts had backed off creating a gap between the block and pump... motor never blew up.
TECH Regular
Joined: Dec 2003
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From: Cherry Hill, New Jersey State
i know it sounds farfetched but i had a similiar issue in which my oil pressure would drop to zero warm and constantly fluctuate but had decent pressure at driving and cold start. Believe it or not my oil pump bolts had backed off creating a gap between the block and pump... motor never blew up.
I have the same thing but in the water pump. The water temperature gauge was flactuating. It drived me crazy. I check it my self the engine and found the water level in the cooling radiator dropps to 3/4 level of the cooling radiator only with no traces of leaks. Went to shop and check the radiator and the water pump and found very intersting thing that causes this mess, it was a loose anchor rod that hold the pump at the left side causing clearance only when the engine becomes real hot at WOT but duirng the cold start no water leak is there. But when real hot the water start to leak in droplets slowly but it evaporate very fast since the engine and the accessiores and you can not see any treaces of leak but you can smell the radiator cooling water vapor only. The shop showed me that and ensured to tightened in cold & hot engine condition...