bigbadon

I have always explained this in ALL my posts. My symptoms (zero psi on dash gage) were identical to mtulett1 post. He does need to verify with gage or look into valve cover....I bet he will see oil flowing. If not he has a problem.

Pelican

I'm just being lazy. I always have to dig back through the thread to see what your pressure actually is. With this exchange maybe I'll remember although I wouldn't count on it.

salad

Yeah but bigbadon doesn't drive a 0331 either

Extra caution is warranted in this case.

bigbadon

Oh yes I DO! Engine date code is 009MX27 It amazes me that so many 2000 & 2001 engines have oil pressure issues. Some are related to the 0331 head but many more are unexplained. Even after complete rebuilds some of these year engines still had low pressure. No one has pinpointed an exact cause. I have heard everything from bad lifter bores to leaky oil galleries due to porous block castings or incorrect cross-drilling. Whatever the cause it has not proven to be too catastrophic as MANY 4.0 have ran a long time with this issue.

salad

Sorry dude. 2004 4.0Ls were made with the 0331 TUPY revision

mtulett1

yes i am loosing coolant and I have no Idea why no puddles under my XJ,....
Cracked Head?

bigbadon

I have said many times that I have a 2004 with a 2000 SALVAGE engine. It was swapped out by a dealer at 40k miles and sent to auction for reasons unknown, possibly to satisfy a custom complaint of low oil pressure! Anyway, it now has 113k and is still running strong.

bigbadon

Or head gasket.....I think you have found the problem. Spend $25 for a oil sample test and you will know for sure.

mtulett1

thanks is there any way to differentiate between head gasket and cracked head?also where do i get the oil test done??

bigbadon

Google "Blackstone Labs" No, not unless you see the crack under the valve cover but you will have to pull the head anyway. Confirm test results first. Mine was losing coolant too and it turned out just to be a bad water pump so you never know!

mtulett1

i would hope its a bad water pump but i replaced that a couple months ago

thanks again

salad

Read: https://www.cherokeeforum.com/f2/00-01-xj-cracked-cylinder-head-overview-118922/

I guess I don't read enough of your posts then

mtulett1

ok so i figured out that i have a cooling system leak right at my water pump. i took my oil filter off and opened it up no metal in it. so i'm fixing the coolant leak today then i need to figure out the oil pressure problem. i don't know if this is right but my oil is reddish. so i think my engine temp is getting to high and burning my oil? then is too thin to maintain pressure? just my guess.

salad

Metal in your oil filter?

Oil isn't supposed to be red. Drain it and see what's in it. Time for an oil change dude.

mtulett1

ya i did that this week pressure was better but still drops out after a longer drive say 40 miles. its fine just around town short trips.