Crazy Oil Pressure

[90growler]

When I first start the YJ the oil pressure reads off the charts and never falls, even at idle. If she is warm and I start it again it reads normal and will rise and fall throughout shifting and idling as it should. I don't drive the YJ but 3 or 4 times a weeks and usually on short trips when the pressure never falls. When I take it on short trips and never restart it when it is at operating temp. she smokes a little when shifting into 4th or 5th and she will spill a few drops and I smell a burning of some sort. I have replaced the Pressure regulator/wiring and the guage is not faulty. Could I have a malfunctioning pump that only acts up at cold start? Is high oil pressure bad? I am puzzled.:roll:

 

[Sparky-Watts]

So, by pressure regulator, do you mean the sending unit over on the left (passenger) side of the block? Those can cause wacky readings, and even leak oil themselves.....mine would read off the scale while running at idle, then drop down low when I'd be driving. I've also read that the oil guages in YJ's have been known to go bad, and is a common problem. How do you know the guage is not faulty? How did you test it?

 

[geopig]

I'd bet it's the sending unit. Get a good one, don't go for the cheapie as I've found out twice that a cheapie sending unit will often fail within a year.

 

[bsnider]

I have a 90 yj with a bad gauge as well its stuck in the up position maybe this is your prob

 

[STEW]

My gauge mists up when i first start up:???:

 

[90growler]

I'd bet it's the sending unit. Get a good one, don't go for the cheapie as I've found out twice that a cheapie sending unit will often fail within a year.

I bought a decent sending unit. Even if, that doesn't explain the small spills and strange smell (like burning oil). It only acts up when the guage is reading off the charts. I got a working cluster from a friend and he never had any problems with it. When it reads correctly, it runs perfect.

 

[redrooster]

If you are leaking and burning oil, then the gauge may be correct. Higher oil pressure at startup is common because the oil is cold and takes more pressure to push it through the block. The warmer it gets, the less pressure it takes to push it.
You might also have some sludge clogging an oil galley in the block or maybe even the filter. There are some products like Restore that will clean the block. Follow the directions, then replace the filter and oil.
BTW... low oil pressure would indicate a bad pump. High pressure means it is working but has an obstruction. Check the rear main seal for your leak.

 

[90growler]

If you are leaking and burning oil, then the gauge may be correct. Higher oil pressure at startup is common because the oil is cold and takes more pressure to push it through the block. The warmer it gets, the less pressure it takes to push it.
You might also have some sludge clogging an oil galley in the block or maybe even the filter. There are some products like Restore that will clean the block. Follow the directions, then replace the filter and oil.
BTW... low oil pressure would indicate a bad pump. High pressure means it is working but has an obstruction. Check the rear main seal for your leak.

I will give that a shot. Sounds like that could be it. Looks like the oil is either leaking from the sending unit or strangly enough, coming from the dipstick tube. It's a very small amount and it's burning on the block.

 

[redrooster]

As far as I know the dipstick tube is a press fit only (no o-ring) so it might leak under high pressure. The sending unti probably just needs some teflon tape if it is pipe threaded. Both are easier to fix than a rear main.

 

[firemanharry]

I had an 89 YJ and before the warranty was up on it Chrysler had replaced the sending unit twice. It would to read high just about ALL the time.