I've been having an intermittent red oil light come on immediately after starting my 08 JK. I shut the engine off, start it back up and it goes off, does not come back while driving. I did check and change the oil filter in case there was something with the filter blocking the oil or something, and the oil level is totally fine. No noise at all from the engine.

So I assumed it had to be the pressure sensor, which I changed last weekend. 2 bloody knuckles later trying to get the damn clip off that is taken care of, but it didn't help. Today the light came on again when starting. Once again stop the jeep, restart and it goes away, never to come back while driving.
Any ideas? It really seems electrical to me but besides the sensor I have no ideas. Currently I have a real oil pressure gauge on order and so I guess I will install that and see if I've got a real pressure problem. But any other thoughts are appreciated. It has only happened about 4-5 times total, so not a big sample size.. but each time it seems like it's when I stopped the jeep briefly like to get gas or some other 5 minute trip and then restart the engine.

 

I like your idea of real oil pressure gauge. Is it throwing any codes??

 

nope, not throwing any codes

 

I believe the light is hot with ignition and the switch grounds out the light to illuminate it. Could be a wire shorting somewhere between the dash light and the oil pressure sender. See attached for 2008 wiring.

 

I think knowing the actual oil pressure would be best. You can have low pressure at startup due to many reasons; (not inclusive by any means), low oil, wrong oil, clogged filter, bad pump, bad sensor and of course bearing etc. I hope it is something simple.

 

Thanks everyone for the responses! I will update the thread when I get the gauge installed.

 

Update: I installed a gauge from Glow Shift. Installation was fairly easy and I like the gauge. But I used a "sandwich adapter" for that goes between the oil filter and the housing. This part I don't like, I had a slow drip leak afterwards. I took it off and back on again, same situation. So I don't know what's up with that but I gave up on the sandwich adapter; I don't really like the idea of having it there anyway. So I removed that and put a T-adapter in order for hooking it into where the sensor goes.

While the gauge was not on there long due to the drip, it did give me some results on the oil pressure. When idling at operating temperature, it read about 10-12 PSI. I am not sure what the standard is, but I think the light should go on well below that. But I need to get the gauge going again and see what it looks like when the light comes on.

Unrelated story: I once had a 1977 Ford Thunderbird with a 400cid V8 and a real oil gauge. At once point the car overheated. After that event when the engine was cold oil pressure read normal, but when it got to operating temperatures the value fell to zero, zilch, nada. High viscosity oil did nothing to help. Drove it 2 years that way with no issues, really weird.

 

That sounds OK for idling.

 

Kind of stuck now, could use some suggestions. I ordered a T adapter but the ones I can find are 1/8-27 NPT which is too small to use where the oil pressure sensor goes. Does someone have a recommendation as to what kind of T adapter to buy?

 

OK I found a thread on another forum that showed me an alternate place to put the sensor: there is a 3/8 plug on the driver's side which is accessible underneath. I removed the plug and used a 3/8 to 1/8 adapter to get the sensor in. It was pretty easy and I think less likely to leak than a sandwich adapter.