oil pressure issue
Thread Starter
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Joined: Jul 2015
Posts: 73
Likes: 0
From: Mobile Alabama
oil pressure issue
95 coupe auto 142k
i had good paper work when i bought it last year. looked like it was always mobil 1 5w-30. i used the same oil and i've been having issues that has definitely become a problem.
picked up a side job about 30 miles away and it's all highway miles.
after the car has warmed up and i get off the highway, my oil pressure idiot gauge hits low enough to make the check gauges light up. never hits zero until the last time i took it out since i had to go get paid for finishing my work.
i got off the highway and at the first stop light the car made a single clunk and the idiot gauge was at zero. anytime i'm on the gas it goes up to around 35-40psi. the issues are only at idle or stopped after the car has hit operating temp for a while.
i've looked into what is causing it. until the clunk happened i had thought about just going to 10w oil since it has been really hot outside. this clunk now says my car is sick.
looks like might just be my sending unit since the oil pump really doesn't fail. the clunk that it did doesn't match up to anything that really anyone else has ran into.
i had good paper work when i bought it last year. looked like it was always mobil 1 5w-30. i used the same oil and i've been having issues that has definitely become a problem.
picked up a side job about 30 miles away and it's all highway miles.
after the car has warmed up and i get off the highway, my oil pressure idiot gauge hits low enough to make the check gauges light up. never hits zero until the last time i took it out since i had to go get paid for finishing my work.
i got off the highway and at the first stop light the car made a single clunk and the idiot gauge was at zero. anytime i'm on the gas it goes up to around 35-40psi. the issues are only at idle or stopped after the car has hit operating temp for a while.
i've looked into what is causing it. until the clunk happened i had thought about just going to 10w oil since it has been really hot outside. this clunk now says my car is sick.
looks like might just be my sending unit since the oil pump really doesn't fail. the clunk that it did doesn't match up to anything that really anyone else has ran into.
Melting Slicks
Joined: Mar 2016
Posts: 2,778
Likes: 580
From: Langley BC
I'm not an expert on LT1's BUT, the first step you should take is to use a mechanical oil pressure gauge that you know is accurate and see what the oil pressure actually is at idle. (C4's are notorious for having inaccurate oil pressure gauges).
If at all possible until you know the true oil pressure at idle I won't risk driving it. Running an engine without enough oil pressure could destroy the motor very quickly.
If at all possible until you know the true oil pressure at idle I won't risk driving it. Running an engine without enough oil pressure could destroy the motor very quickly.
Last edited by DMITTZ; Aug 8, 2016 at 09:24 PM.
Thread Starter
Advanced
Joined: Jul 2015
Posts: 73
Likes: 0
From: Mobile Alabama
yes i know the dash gauge is known to be inaccurate which is why i didn't worry about it at first. i did some reading already and it was more than likely ok since it was driving just fine. the clunk and seeing the dash gauge drop completely off is when i knew i had a problem.
Melting Slicks
Joined: Mar 2016
Posts: 2,778
Likes: 580
From: Langley BC
Yes, I agree. Hearing a clunk and then seeing no oil pressure sounds like a problem.
However, since you said you still had oil pressure while driving after that and that before that the oil pressure at idle seemed low, its hard to say what that clunk actually was....
Again I am no expert on LT1's so If I'm wrong correct me, but if the oil pump broke somehow I would think you would have little or now pressure at any engine speed, Not just at Hot idle...
If it were me the first step I would take is to confirm the true oil pressure, that way you will know for sure if you have a problem.
However, since you said you still had oil pressure while driving after that and that before that the oil pressure at idle seemed low, its hard to say what that clunk actually was....
Again I am no expert on LT1's so If I'm wrong correct me, but if the oil pump broke somehow I would think you would have little or now pressure at any engine speed, Not just at Hot idle...
If it were me the first step I would take is to confirm the true oil pressure, that way you will know for sure if you have a problem.
Burning Brakes
Joined: Jun 2016
Posts: 761
Likes: 66
From: Fitzwilliam New Hampshire
My 1994 c4 LT1 103000 miles,I went with Mobil1 10w40 high mileage full synthetic raised oil pressure 10 lbs at idle and driving.Dont think its to heavy for summer use.5w30 for new tight bearing clearances and cold temps.I checked autozone specs on this good for older engines that reqiure synthetic.But still would install new gauge for peace of mind.
Last edited by A Peter C4; Aug 8, 2016 at 09:51 PM.
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