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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: muleystruck on June 30, 2017, 11:11:30 AM

Title: loss of oil pressure
Post by: muleystruck on June 30, 2017, 11:11:30 AM
my truck is an 86 Scottsdale with a 4.3 and mm7 trans. coming home from work I lose oil pressure. I shut it off, waited a while, started back up, knocking, shut down again. called my bro to bring his trailer, took about an hour or less. had to start it to get on trailer and oil pressure is fine. hauled it home anyway. unloading the truck had to start it, still normal oil pressure. I know the pickup tube could be stopped up then releasing the blockage. this hasn't happened before and I'm concerned about driving the truck. don't want to damage the motor. should I pull the pan and check if trash is present before driving it again? I don't know the exact mileage on the truck as the speedo cable was shot. any help is greatly appreciated. muley
Title: Re: loss of oil pressure
Post by: Irish_Alley on June 30, 2017, 11:17:23 AM
did you check your oil level? is it thinned out or saturated with gas?
Title: Re: loss of oil pressure
Post by: bd on June 30, 2017, 11:41:17 AM
In addition, when was the last oil and filter change performed?
Title: Re: loss of oil pressure
Post by: m3talc0re on July 04, 2017, 03:08:41 PM
I'm following this because I keep losing oil pressure, too, and I'm not sure where. I changed the valve cover gaskets (they were shot), but the problem persists. Mine will cold start with good pressure, but after driving a while, then stopping at a light or something, I'll lose almost all of my oil pressure and the Choke light comes on. Plenty of oil. When I start driving again, the light will stay on, but I'll have around 20 psi on the gauge, until I stop again and it'll just bottom out.
Title: Re: loss of oil pressure
Post by: VileZambonie on July 04, 2017, 07:20:13 PM
What are you running for oil?
Title: Re: loss of oil pressure
Post by: m3talc0re on July 05, 2017, 08:59:03 AM
I'm running 5W-30
Title: Re: loss of oil pressure
Post by: VileZambonie on July 05, 2017, 11:34:42 AM
Run a thicker oil
Title: Re: loss of oil pressure
Post by: Stewart G Griffin on July 08, 2017, 10:03:40 AM
Run a thicker oil

^^^This^^^^
But also check:

1) What brand oil filter you are running.

2) Is the gauge/warning light acting up?

Trash in the pan could be a cause, but i would check 1 and 2 first.