loss of oil pressure

Also NEVER flush a engine that you suspect oil pressure problems with, it can make matters worse. If pressure has been verified, the bearings are likely worn out. One thing you can try to do to milk it out for a while is to use some 15w40 in it as it should boost pressure. DO NOT use 5w30 EVER if you are having oil pressure problems.

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If you live in a warm enough climate, maybe even a 20W50 oil might help. John

If you live in a warm enough climate, maybe even a 20W50 oil might help. John

I had a 1977 Mercury Cougar with a 400M V8. It use to do the same thing. If I remember correctly, the main bearings were worn paper thin (gouged in spots) due to previous owner abuse.

I had to rebuild it. Since this was my first attempt at rebuilding ... I knee jerked and put in a high volume oil pump. Then I had the opposite problem ... Everytime I started the car (when cold), I'd blow

1/2 quart of oil out of the rear seal because of too much pressure.

Lessons learned ...

Craig C.

To much oil cannot be good too as you learned the hard way. Usually the rod bearing go first when mains start to wear because they receive oil via cross drilling through the crank mains. ALso in HD applications, a aux engine oil cooler can boost oil pressure and extend engine bearing life a good bit under heavy loads. (all diesels have them, they could not live long with them)

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You might want to rent a mechanical oil pressure gauge and test your pressure with that first. You could have a faulty electrical gauge that is causing the problem.

Thanks to all for the input on my problem. I have discovered that the truck had been run HOT. I ran a quart of tranny fluid in it for about 30 miles to flush it. When I got into it there was some stuff on the pump screen and the oil filter weighed about twice what any other one that I've removed. Under the valve covers was where all the heave stuff was, about

1/2" thick and cooked on the inside the covers. I will be flushing it a couple more times to see what happens. anyone got any other ideas. thanks

My suggestion is you clean out manually what you can and then for next several changes, use and good light weight oil(like 5w30) and change oil and filter every 1000 to 1500 miles top (sooner if oil gets really dirty) and not flush it quickly because when you do you can overwhelm filter and then in plugs up and bypass the gritty oil through bearings. I have seen engines damaged by quick flushes.

Is it ok to put tranny oil in a crankcase even for a short amont of time?

John

Not really. Put some between your fingers and feel it. Does it feel like it offers the protection that motor oil does? If you are talking about short time like a few minutes to help flush the block, then maybe but there are cleaners on the market (along with kerosene) to do that. Now by tranny oil, I take it you are talking about ATF.