Lost oil pressure
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Elder User
Joined: Apr 2004
Posts: 535
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From: Tucson, AZ
Lost oil pressure
The gauge in my '78 will read no oil pressure at idle but when I start going it goes back up to normal, I figure first I'll replace the stock gauge with a mechanical one and if it still reads low I'll have to replace the oil pump. If it's the oil pump what's the easiest way to get the pan out? (ie Lift the engine up, etc.)
New User
Joined: Sep 2003
Posts: 12
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Just did this.
About two months ago coming off the highway I noticed my pressure drop to zero. Gave it throttle and it came back up. Got home and let it cool down. Drove it and got it up to temp and everything seemed fine. Back to work the next day and the pressure drops again. Thought it was the sending unit. Replaced it since it was a cheap and easy fix. Same problem. Decided on the mechanical guage. On start up, psi is about 50. Up to temp and the pressure dropped to 12 psi or so. Decided that the pump swap was my last effort. Put the new pump in yesterday and same pressure drop is happening. After consult with a buddy who is helicopter transmission design engineer, he said that the motor is finally getting loose. Recommends running a 20w-50 oil. I am going to try this tonite and see if I can get the pressure to stabilize. One thing I can say though is that every time the pressure drops I don't get any lifter clatter or bearing noise. Thinking about just disconnecting the sending unit. Hope it turns out for you.1992 F-150, 4.9, just turned 229,000 miles.
New User
Joined: Jul 2004
Posts: 24
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I just rebuilt my 300 and at idle i get no oil pressure. moving i get the needle half way. this could be a sending unit which i didnt change but it did the same thing even before i rebuilt the motor so i wouldnt worry
Junior User
Joined: Aug 2004
Posts: 58
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Its been a while since I have driven my truck...well 3 years almost. Finally got it up and running last weekend, did a major brake/rear overhaul and now I am driving it again. I think I used to run a thinner oil and that would keep the pressure up, but now I am running 10w-30 and it is now suffering from no oil pressure at idle, but it goes into the lowside of normal once I start moving, and then at speed its in the middle. I have a new motor, that was installed 4 years ago, with only 14k to date miles on it. Do ya'll think a thinner oil would help? 5w-30 maybe? I think that is what I used to run.
