Hi there everyone,

I am currently looking to purchase a 1998 Ranger 2.5L, 5 speed truck. Test drove it the other night and I noticed that the oil pressure gauge was jumping (frequently!) between 0 and mid-scale. It didn't seem to have any rhyme or reason behind the jumps (i.e. - when the engine was warm and idling - it didn't go to 0 and stay there as I would expect if it was an actual oil pressure problem). My question is this - how do I try to figure out if there is a real oil pressure problem or if it is just an electrical gremlin affecting the gauge? Is this sort of thing common in the Rangers? Thanks for any advice!

Eric

 

Common.

~$10 part at any auto parts store.

It's not a "pressure gage" per se, it reads mid-scale if oil pressure is above ~8 psi.

In other words, it's a pressure switch.

Typically acts as you described AT IDLE. If it's doing it at higher RPM, I'd make sure that switch gets replaced BEFORE you buy the truck.

Could be as simple as a loose connector on the pressure switch too.

I've seen it happen when the vehicle has a low idle problem. In that case, the oil pressure switch wasn't bad, the pressure was simply low due to low idle rpm.

 

Sounds like the oil pressure sending unit "switch".

 

Thanks for the replies. That's what I had hoped - a sending unit (rather than an oil pump and related damage). How tough is it to change the sending unit on the 2.5L 4 cylinder? Thanks

Eric

 

I don't know, but in the manual, it has a picture which says "Intake Manifold shown removed for clarity".

Makes it sound like a PITA (pain in the ...) to get to?

They also specify 13 ft. lbs torque and using a teflon pipe sealant. I think the new one will come with sealant already on the threads though.