Oil pressure problem

[Channeled]

I just bought an 87 GN and am having problems with it losing oil pressure and heating up while in traffic. On start up it sits around 40 psi but after the water temp hits around 150 my pressure drops to around 10. Is this pretty common with turbo cars? I have no idea what weight oil the previous owner used in it. Should I try a heavy 20W-50 or could there be other mechanical issues?

 

[BlackBandit]

It's a good idea to change the oil in any car that's new to you. I would stick some 10w-30 in it and see what happens. 10 psi is a little low but not bad. The more important thing would be what your oil pressure is around 2200 rpm, when cruising, and at max RPM.

Edit: I suppose I wouldn't change the oil in a brand new just off the lot car. That's about the only exception.

 

[Turbo1dr]

10 to 15psi at idle is about normal for a Buick V6 engine of the 80's with a few miles on it.

In the Summer I'd use 20-50 oil.