help with low oil pressure - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

08-11-2003, 06:05

I just recently purchassed a 1990 cougar. It has the 3.8 f.i. engine. The car runs good, sounds good, no smoke, however the oil guage is sitting on zero. Does anybody have any suggestions???? oil pump, oil sending unit, digital guage,electrical component?????? Which is more likely to be the cause??? If it is the oil sending unit, where might I find it on the motor??? Please help???? I don't want to pop this engine. It is showing 140,000 miles. Thanks!!!!!

Bobnoxious · 08-12-2003, 10:49

I am not familar with your model but I am assuming you mean the oil pressure gague? The dip stick shows enough oil? Sounds like the sending unit. I don't know any recommended way to get a new one. Beware of O'reillys. I used a fuel pump I bought from them for our jeep cherokee and it was junk.

big1 · 08-12-2003, 14:10

Oil pressure sending unit should be mounted on lower left side of timing cover. Don't automaticly replace it. First ground the wire with the ignition on to verify that the guage is working. Second if the guage is working do a manual pressure check by installing a manual gauge in the port where the sending unit came from. If the pressure is within spec"s then install a new sending unit. When you buy the unit ( if needed) be certain to tell the clerk that it's for a digital guage.

08-13-2003, 09:27

Thanks for the info. I will give it a try and let you know how it goes!!

08-15-2003, 05:19

I found the sending unit, it was where you said it would be..thanks...I grounded the wire to the motor and the digital guage went to dead center of the guage. I took the sending unit out and put in a manual guage. The guage read between 60 and 80????? Is this a little high??? or is this normal for this engine. I didn't have the guage screwed in very tight due to the limited space I had to work in, so it blew a little oil out when I checked it....could that cause unreasonably high pressure readings ????? Or am I just used to chevy 350's that run with 10 to 0 psi.
I am not looking forward to putting a sending unit back in..........This has got to be the hardest sending unit I've ever seen, to get to !!!

big1 · 08-15-2003, 07:21

60-80 psi is real good, and in most case's the guage will only center so it's good. Ford dealer's sell an extention for the sending unit. It was standard on older 'Windsor" block's. It will help a bunch in reinstalling. Glad I could help.