Hi All, just acquired a '01 cherokee sport with 168,000 on the clock. First day driving noticed that when hot the oil pressure drops to zero at idle and also that it's drinking coolant like I drink Gatorade and none of it's leaking out. After reading posts on this and other forums and after replacing the oil pressure sender and cleaning out the passage to it, I've determined that the block is most likely cracked and the bearings in the engine are worn to such an extent that it can't build up appropriate oil pressure. My plan of attack it to get a new block from Clearwater and also replace the easily accessible bearings. Question is; am I crazy to undertake a job of this magnitude and what are the chances the oil pressure will improve? Any and all comments are welcom and thanks!

 

How did you determine this?

Did you check to see if your oil has coolant in it? You could have a coolant leak.

 

Don't jump to any conclusion just yet. The most common problem for coolant lose in your year is a cracked head and not a cracked block. You need to do a lot more investigation on your Jeep before you can say that it's a cracked block. One question. Didn't you check it out before you bought it or at least test drive it???

 

Sorry, mis-spoke! I meant to say that I thought it was the head that was cracked not the block! I'm sure the block is fine. Didn't test drive the car. Sort of inherited it and don't want to start dumping money if it's a lost cause. Thanks!

 

A cracked head on the 00-01 is not uncommon. Instead of reinventing the wheel, I suggest you SEARCH and you will find a lot of threads on this problem, how to properly diagnose this problem and options.

If the head has been cracked long enough, the internals of the engine (bearings, etc) will be damaged to a point of no return and replacing or rebuilding the engine right out of the gate may make more sense.

Do some homework and some testing (to confirm the head is indeed cracked). Lots of information on all of the Jeep forums and the web in general for you to check out.

Good luck and keep us updated!

 

Thanks for your input! I'm about to do all the necessary testing. If it turns out to be the head and I find a 2003-4 wrangler motor, can I swap the entire thing or it it just the head that's a shared part?

 

The 2003-4 Wrangler engine is different from the Cherokee engine as far as the mounts and the way the brackets bolt onto the block.

 

XJ
Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange.

2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange.

XJ/ZJ blocks and 2000+ TJ/WJ blocks do not interchange without significant modifications. (1991 to 1995 YJ and 1997-1999 4.0L TJ Wrangler blocks will interchange in XJ/ZJ and visa-versa).

TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ.

　

XJ
: "Regular" (not Grand) Cherokees 84-01
ZJ: Grand Cherokee 93-98 (Gen1)
WJ: Grand Cherokee 99-04 (Gen2)

YJ
: Wrangler 87-95 (Gen1)

TJ
: Wrangler 97-06 (Gen2)

 

What kind of oil filter is it running?

 

I have a 2001 with the same problem. I replaced my oil pump, sending unit, and put in extra thick oil hoping to solve it. Turns out cam bearings are shot, so I'm just driving it into the ground while I slowly save up for a new engine, possibly stroker.

sounds like you have a cracked head .. Maybe get one of those high volume oil pumps, it could help.

 

first thing to do with those symptons....

step 1-check oil. does it appear milky? if so step 2

step 2 pull oil pan pull rod caps and 3 of the 7 main caps. inspect the bearings and crank journals. if the bearings are worn out but the crank journals are fine as in still smooth no sign of being grooved on any of the journals. i would install new bearings. next step 3

step 3 pull cylinder head inspect head gasket, send head off to be checked at local machine shop. replace neccesarry components.

step 4- now would be a good time to install new piston rings/inspect cylinder bores. replace neccesary components.

 

No it won't. Useless. Waste of money and time, like you have already done.

 

How will a high volume oil pump going to help with a cracked head??? Please explain how you think this would be a good idea and how it would help...

 

Glad I didn't suggest a high volume oil pump. LOL

True though; a high volume pump in this case would be like putting lace curtains on a pig's ****.

 

LMAO!!!
Good way to put it!