Oil Pressure problems

**GwinnettXJ** · 08-31-2002, 10:48 AM

I just recently got my air conditioner fixed. It finally blows cold again. I also had a new Flowmaster Delta 40 put on it. The very next day, I changed my oil and got a new battery. A week later (yesterday) my check gauges light came on. My oil pressure was way low (never happened before) and my engine was running hot (again...never before). Any ideas as to why this has all of a sudden started to happen?

Watto · 09-01-2002, 01:07 AM

The exact same thing happened to me on both my '97's but without the high engine temp. It turned out to be the oil pressure sending unit. I was getting erratic oil pressure readings, usually low and my check engine light came on. Replaced the sending unit, problem solved. 'Cept not sure what is causing your engine to run hot.

**GwinnettXJ** · 09-01-2002, 11:51 AM

Well...it only showed that it was running hot for about 15 seconds. After the light turned green and I started driving again, it went immediately back a regular temperature and it hasn't done that again. However, the oil pressure continues to change even though it was not as much as it was on that singular occasion. I guess it could've been a computer thing, and not that the engine has been restarted several times it's worked itself out. Should I not worry about it anymore?

Watto · 09-01-2002, 03:32 PM

Well, here's what I did:

I took the oil filler cap off and looked down into the valve cover to make sure there was ample oil up in the top end. I also pulled the breather hose to the air filter off and looked in there as well (beware, it's a pain to get back on). The oil was good, so I figured it was just the sending unit, or the guage itself. This is my second '97 XJ, and I just purchased it used from a dealer with a 90 day/3,000 mi warranty. I took it in just before the warranty expired. They confirmed it was the sending unit and replaced it. It is a $75 dollar part (stealership price), and should be fairly simple to replace yourself although I have not personally done so.

The same thing occurred with my wifes '97 XJ and the dealer repaired it under the factory warranty. Just make sure you are getting oil up into the top end. If you are, you are probably OK. When my check engine light came on, I had almost zero oil pressure according to the guage. After a while, the warning lamp went off on its own and the guage readings gradually rose, but were erratic until I got the sending unit fixed. I don't know how many miles are on your Jeep, but my wife's sending unit went bust around 24,000mi, and mine currently has 39,000mi on it. Low miles, but still 5 years old.

The technician I spoke with mentioned that the instrument clusters on '97 and later XJ's have been problematic. I also get crazy readings from the fuel guage, but fortunately that is a recall issue. We had the recall work done on my wife's, but not on mine yet. So, if I was a betting man, I'd say it's just your sending unit and nothing more as long as your motor isn't too hot, and you have oil up in the top end.

Hope this helps.

**GwinnettXJ** · 09-01-2002, 09:27 PM

Sounds like you may be onto something with the sending unit. I think I'll get it looked at on Tuesday. Mine has 137,000 miles on it, so I guess it's about time for things like this to start happening. Thanks for your input.

Tony

Wolf_XJ_1985 · 09-01-2002, 10:11 PM

Hehe Mine's 15 years old and has 137,748 miles on it and at the moment runs like sh!t. Of course it's been sitting forever. I can't get the dang thing to stop missing.

I had my oil pressure light come on once for no apparent reason, but I think the sender unit may be bad. I only have indicator LIGHTS. Hmm...a question I'll post a new thread on.

Caio.

**balloo93** · 09-02-2002, 07:05 AM

My 93 sport oil gauge dances all over the place. I plan on just replacing the oil pressure and temp gauges with mechanical ones. They are a hell of a lot more accurate.

You may want to dissconect the battery, due to the fact that you did the exhaust. The new OBD commputers are very fickle when it comes to upgrades.