Hey guys,
My 94 318 was losing a ton of oil and finally I found the problem and replaced the oil sending unit. Great NO LEAKS!!! However, since then when I drive a while and then my truck idles in gear the oil pressure drops to nothing and the light comes on. If I shift into neutral I dont have this prblem. My engine never sounds any different and there are no nocks or smoke. Is it just a coincidence this happened after the sending unit was replaced? Has anyone ever had this before? It never happened before replacing the sending unit. Thanks eveyone - - This site has been a great help to me and my father.

 

Glad you got the leak fixed, but Yeahyour problem isnot uncommon as far as I know. My 93' 3.9started doing the same thing before and after I replaced the oil sending unit. The gauge wouldzero and the light would come on at an idle sitting in park mostly. It made me wonder what was going on at first but the motor never labored or knocked so I figured it was a gauge flaw. So YEAH its just a coincidence and nothing really to worry about unless it starts knocking or sounding odd. I am happy to share knowledge.

 

Where did you get the sending unit? If from a Auto Zone type store then I would get a new one from the dealer.

 

I had a mechanic do it. So I would assume it was from somewhere like AutoZone. Is there a problem with it, other than the guage issue?

 

I once bought a water temp sensor from Kragen Auto Parts, like Auto Zone a neighborhood auto parts store. About a week later the engine would not idel and did not run right. Long story short I took it to the dealer and the problem was the water temp sensor. Had the same thing happen with a distributor cap. Since then I get my eletrical parts from the dealer. The only corner store I might exempt would be Napa they seem to carry a higher quality of parts.

 

I'd second that. Check your local parts store like Napa, Carquest, etc...usually they carry a couple lines of parts. one cheaper but lower quality, and another line of higher quality/higher expense. Sometimes a little to a lot more costly, but usually worth it.

 

Before buying anything, check to make sure the mech. installed it tight and it's not still leaking. Also, I believe there are two different switches (although I'm not 100% positive)...one works with the gauge and one works with just the light. Maybe he used the wrong one?

 

Are these switches easy to sopt before I take the truck back to the mechanic?

 

Should be at the rear of the engine, next to the distributor. It's not hard to get to, but you'll have to remove the air cleaner. If you have 4 wd, you'll probably end up laying on top of the engine in order to get a good enough look down at it (or at least standing on a step ladder).

 

I get this problem when I'm driving, not idling. I see that a lot of people seem to get this when idling, but I'm just the opposite, when I'm driving along my oil pressure drops to nothing and the light comes on, as soon as I let off the gas it comes back up, press the gass and it drops again. I'm going to replace the sending unit this week.