So my check engine light came on today and my oil gauge was going crazy. I stopped and checked the oil but it was good. So on the way home I noticed that every time I slowed down/came to a stop my oil gauge would drop very rapidly and if I stayed at a stop long enough (2ish minutes) my engine temp starts to climb over 210 degrees. But then when I would start moving again the temp dropped back to normal and my oil gauge also went back to normal. So my guess is my engine isn't getting enough oil? But I really have no clue. So, if anyone could offer any insight to my problem I would be very thankful. Thanks.

 

How does your oil look? Any milky stuff? Does the engine ruin at all rough when the pressure drops?

 

Thinking head gasket or cracked head?


My 98 TJ's oil pressure gauge drops when I slow down, but intermittantly. Engine temps never raise, though.

Do you have full coolant?

 

Chilidog: no and no

Gee: the temp didn't go up much, just a little above 210, and I don't know if I have any of that...

 

Anyone have any clue?

 

I'd suggest finding out if your oil pressure is really low or if there is a problem with your gauge or sending unit.

It will probably help to find out what codes have been thrown.

 

Alright I'll see if I can get my mechanic to check the code tomorrow

Oh and how can I check to see if my oil pressure is low on my own?

 

Well I took it to the shop just now, I'll stop in tomorrow and hopefully he'll know whats wrong

 

The only way I know of is to temporarily install a mechanical gauge. Probably the best place to put it is where the sending unit is currently located. I would hope that is what your mechanic will do. Good luck!

 

wildbill1 is correct.

The ONLY strategy for low oil pressure readings on your factory dash gauge is to CONFIRM.

And the only way to confirm is with a mechanical gauge temporarily installed where the oil pressure sending unit resides.

Compare the mechanical gauge readings to your dash gauge readings. Then you'll know.

The oil pressure spec for the Jeep 4.0 is as follows:

*Not less than 13 psi at HOT idle
*Between 37-75 psi over 1600 rpms

A question for you......are you losing coolant from the coolant reservoir? That is the #1 symptom of a cracked head. Not saying that is your deal, but as an owner of an 00-01 with the "infamous" 0331 cylinder head, you MUST keep an eagle eye on your coolant level.

Let us know what the shop finds!

 

Well driving it home yesterday, the oil pressure was below 10 during idle. And it usually stays at 40. And yea I checked the violent and it was full so I don't think it's a cracked head. I did read about 2 things that could cause the oil pressure to drop, and I have both of the symptoms. 1. Some spring in or around the sending unit or something is broken, which causes the oil pressure to drop at idle, which mine did. 2. Bad bearings, which makes a noise in the engine when at 2000rpm, which mine also did. Ill ask my mechanic if he's gonna do a manual check though. Thanks for the help

 

Ok well it turns out that the check engine light was caused by a cylinder 3 misfire, so that's getting fixed Tuesday. As far as the oil pressure I'm gonna put in a new sending unit Sunday and change the oil. Hopefully that will fix the problem and I can get on to replacing the leafs

 

Fixed how?