[billw]

Hello all. First post here, so bear with me. Up until recently, I've had no issues with my 4.0L WJ. Although it's a 2002, it has "just" 128K miles on it. This Monday (it was cold here [for us] this week, in the upper 40's on Monday), I heard a very noticeable whooshing sound coming from the engine. At the same time, I also noticed that the idiot pressure gauge was reading all the way high "H" when cold, and staying there over 1K RPM for about 30 minutes. After it warmed up, it want down to mid gauge at idle, and about 3/4 to H when driving. This is very abnormal, as the pressure usually reads just above mid point most of the time, and varies little.

My first thought was that the oil pressure sender was bad, EXCEPT for the noticeable whooshing sound. To me, it sounds like a bad restriction, like high pressure water being sprayed under water. Some of the few postings I've read, mentioned that the oil pump was in bypass. I'm quite familiar with hydraulics, and that to me is the most plausible explanation.

The concern I have is if there's a restriction that's causing a high pressure bypass condition, than I suppose it's possible that some parts in the engine are seeing low oil flow/pressure, which can make for a bad day.

One note. I'm the original owner, and have always used 10W30 oil for the engine, except the last change, where for the first time, I tried 5W30. That was 2300 miles ago since I last had the oil changed. I don't know if that has anything to do with the current problems, but its a data point.

If it was just the sender, that's something that seems easy enough to do, but an oil pump means the repair shop, and the ever present $500 minimum repair cost (for anything it seems).

Any suggestions?

Thanks,
Bill

 

[thompsb2]

Hello Bill, I see noone has given you any ideas. I am NOT an expert on Jeeps, I own a 2002 GC 4.7 and am learning something all the time. Are you hearing any new mechanical noises from the engine and is the oil pressure still running high? It's possible the relief could have failed and is bypassing the oil filter, I guess. If so; that will not be good for your engine. One thing you might check out is the SeaFoam web site, I have not used this in my oil' I have used it in the gas tank to clean the fuel system. It might be possible for you to replace the oil pump yourself, I have done this on other makes in just a few hours. You might want to check out Rockauto on line for parts, I have bought several things from them and recieved the parts on time in good shape.

Good Luck

 

[billw]

Thanks for the reply. Unfortunately, I live in a community that makes it very difficult to do any major car work, other than lifting the hood in the drive way. I've worked down to the nuts and bolts of engines in the past, but that's just not an option now.

My quandary (and risk) is to try the SeaFoam product and hope for a miracle ($12), get the oil changed now ($35), or take it to a shop where they'll always tell me that it will cost over $500 to replace the oil pump (whether or not it really needs it).

 

[Frango100]

Using 5W30 instead of 10W30 should bring the oil pressure down a bit when cold, but still be the same at operating temperature. I would start changing the oil pressure sender, or measure the pressure with an external gauge for comparrison.

 

[billw]

Using 5W30 instead of 10W30 should bring the oil pressure down a bit when cold, but still be the same at operating temperature. I would start changing the oil pressure sender, or measure the pressure with an external gauge for comparrison.

That's exactly what I thought, but it's just the opposite of what you would think should happen. I'll admit that the oil pressure sender may be bad too, but again, that's why I'm still leaning towards the oil pump. I only mentioned the oil grade/change as something that is new and different from its normal operation over the past 11 years.

As for SeaFoam, while it appears from many accounts to be a miracle potion, I'm not so sure in this case, especially in that my particular condition does not seem to be a common problem in many cars, not just my WJ.

UPDATE: Had the oil filter alone replaced, and no change, still high. Oh, well, so it's off to the shop we go .. he, he, ho ho :giveup:

 

[THAT_XJ_GUY]

Easy oil pressure sender check

Turn key to "run" position with engine off.
Does the oil pressure gauge show pressure?
If yes. You're sender is bad.

 

[billw]

Does the oil pressure gauge show pressure?
If yes. You're sender is bad.

The sender doesn't register any pressure with key ON, engine OFF. With that being said, I took the jeep to the shop today, and the sender was in fact bad. They replaced it, and the pressure indication is normal again. However, it doesn't explain the whooshing sound heard last week when it was cold.

It's been very warm here in Orlando late last week (high of 87 on Saturday), and 82 today (this December, isn't it?), so no sound was heard. But there's a "cold" front coming in, so we're supposed to have lows in the 50's tomorrow night, so we'll see if the sound comes back.