Hi everyone.

Last week while driving my '84 (LG4) to work I noticed the oil pressure gauge was sitting just barely in the upper edge of the red zone. I thought this was odd since it normally shows about 40psi at all RPM. Everything 'seemed' normal so I continued on.

I watched the oil pressure and the engine temp which was normal as always. If I saw the temp start to climb I would pull over immediately. Suddenly during the commute (50 miles) the gauge jumped up to 40psi in one big swoop. Then a few miles later it went back down.

Now, if I really had this little oil pressure the thing would probably be seized up by now. Could it possible be a shotty ground to the pressure sending unit? Or a bad one? I know in my corvette that when the sender loses it's ground connection it will peg at 80psi.

The check engine light also started to pop on for about 10 seconds at a time randomly at about the same time. Perhaps it is simply coincidence.

Thanks!

 

Try the sending unit first... they have a reputation of going bad. If that doesent do it, it might be a sign of bottom end trouble eg: bad oil pump, main and/or rod bearings etc...

 

It could be the sending unit. It could also be the pressure relief valve being stuck open in the pump. My car had a problem of showing 30 psi sometimes, over 60psi sometimes, and normal45-50 psi. Rather than replace the pump, because of the relief valve sticking, I flushed the motor with a cheap can of gunk 5 min. flush. It cleaned the valve enough to make it read normal again.

 

same thing happened to me... after a year or normal PSI (around 30) it just drops to flat 0... so i coasted home... thought and looked into the Chiltons.. then took the truck up town talked to the guy at the local parts strore... he said this

1) Sending unit, b/c its cheap and easy or it could..

2) check the gauge, go buy a mech. oil psi gauge and just see if it corrensponds with the dash...

3)then you may have some problem, could either be the bearings or the oil pump...


yours sounds like the sending unit, if you had 0 oil psi then you would hear and knock deep in the motor as if some one was hitting the crank with a hammer... i would say its the sending unit it cost like 10 bucks and takes 10 mins!

 

mine registers 0 when its cold but after driving about 10 min i flick the gauge a couple of times it pops right back to normal. only happens when temp outside is below 30 or so.