A couple of years ago I had and issue where my oil pressure would drop to 0 after about 15-20 minutes of driving. After searching these forums I found it was the oil pressure sending unit. I had this replaced and all was well for a around 6 months.

After about 6 months I had the same problem return. Since then I have replaced this sending unit around 4-5 times. It seems to be fine for a few months and then problem returns. I am really getting sick and tired of replacing this unit as it is pain in the a$$ to remove and replace.

Anyone have any idea why this keeps going bad or if there is a bigger problem. The engine sounds fine when the oil pressure drops to 0 and the oil looks good.

Every time this fails it takes about 15-25 minutes of driving before this starts happening. It also only goes down to 0 when I come to a stop. So as you can imagine it is very annoying to get the DING DING at every stop.

Any help would be appreciated.

 

I'm assuming you have verified your actual oil level and never have low oil correct?

Also, have you ever connected a mechanical oil gauge to the port and used that as a second opinion to the electric gauge? If not, that might be a good idea. At least use it long enough to get some baseline readings about where your oil pressure should be during certain driving conditions.

Also, and this may be a stretch, check the engine ground. The oil pressure sender, like most engine senders and sensors, uses the engine as a ground. If that ground is failing or intermittent then maybe that's killing the sender because you're basically watching it turn on and off thousands of times every time you drive the truck...and after a few months of that, it finally just stops working.

 

Yes, the oil level is always good. That is the first thing I have checked.

I have not tried this, but until this starts failing, the oil pressure reads correct. I really don't think there is anything wrong with the oil pressure, but I do wonder if this is a grounding issue. It would make sense as to why these keep burning out.

Thanks for your input.

 

Are you using any oil additives?

I had an '87 GMC and used those fram filters with teflon additive in them. My oil pressure sending unit would slowly crap out from the teflon building up in it.

 

Teflon tape on senders that utilize the engine for ground defeat the grounding capacity of the unit.

 

Nope, none at all.

Never thought of the teflon tape. I can't remember if we put that on the last one or not. I will have to check with my buddy that helped me with it.

 

i'd guess that its getting sludged up.

do you still have any of the old sensors that you can look at?
if so, rinse it out with a little brake cleaner or carb cleaner and see what comes out.

if not, remove your old one, clean it, reinstall. see if it helps.

edit - if teflon tape was the problem, it would have been a problem from day one.

 

I did talk to my buddy and he said we did put the teflon tape on. Would it not leak oil without the telfon tape?

I do have an old one. I will clean it out and see what I get out of it.

 

I did just spray out an old one that I had kept and it was clean as could be. No sludge, no nothing.

 

hmm.

i've never heard of anyone with that many failures.
you're like me and my IAC marathon a few years ago. i replaced it about 4 times before i realized it wasn't the problem.

i wonder if there is any way to ohm test it under air pressure?