I've got a 1987 F150 6cyl with 71000 miles. What can indicate low oil pressure besides the obvious of being low on oil? I noticed the oil pressure gauge indicated below normal pressure, checked the oil and it was 1 qt. low. I changed the oil&filter (6 qts) and the oil gauge is still indicating below normal pressure.

 

Low oil level won't nessesarily cause the pressure to drop unless you are like 3 quarts low. I think your problem is either with your oil pump (which is the best case scenario) or the rings and other internal components are worn out. With only 71,000 that isn't likely to be the problem.

I would try replacing the oil pump first. The oil pump is cheap (like $30) but you have to jack up the engine and unbolt the motor mounts to get the pan off.

Actually the very first thing i would do is hook up an oil pressure gauge to verify that the one on your dash is working correctly and that the pressure actually is low.

-Jon

 

I know that the newer Ford vehicles have electronic idiot guages for oil pressure not a true "pressure" guage. Not sure about the 87s though. If it is electronic the it is probably a bad sending unit.
Check it out.

Hobbit

 

At least you've got a real gauge and not one of the fancied up idiot lights like on my '01.

Natty