TheSamba.com :: View topic - Thoughts on oil pressure warning light- 91 cabby

Tue Apr 28, 2009 6:23 am

I got this car this past week. The oil pressure light would come on at idle after it warms up. I tested the switch on the head by grounding it out, test worked

I've
A) changed the oil with Castrol 40w, and used OEM filter problem went away for a day
B) Pulled the oil pump, it's within specs
C) Refilled with 20-50 castrol

I hooked up an aftermarket guage and got 20 psi at idle, car was still pretty warm. It then did good for the better part of a day or two, then during a long stop light to stop light cruise, came back on. Only when the temp guage reads over 100.

Outside temps were above 85 during all that^

SO, I found the coolant level a bit low, and the radiator return line was very pliable and probably crimping itself shut when pressure built up. I also found a disconnected ground from the cylinder head/valve cover.

Now my temp gauge seems at a steady 80 or so, and oil pressure guage seems around 1.5-2 bar at idle, BUT the outside temp is below 70.

Thoughts on whether or not the coolant level/etc could have an impact on my oil pressure, or am I being suckered by the low outside temps?

Tue Apr 28, 2009 4:55 pm

I replied on Vortex, but I'll reply here too:

Test the low-pressure switch on the cylinder head by removing the yellow wire; if the warning light stops flashing, the switch is faulty and should be replaced. The 0.3 bar switch is normally closed until it senses low oil pressure, at which time the switch opens, breaking the path to ground.