00 XJ Low Oil Pressure

[Michael20mac]

i recently bought a 2000 xj and i did a few things for maintenance because i did not know the history of it. obviously an oil change as well as a supper flush on the coolant, spark plugs and a few minor things. my water pump blew on the freeway i overheated for at most a minute until i could pull aside. i replaced it immediately. it ran great for 3 weeks then i ran into a low oil pressure issue. i used a mechanical gauge it read the same as the dash gauge. i still replaced the sending unit just because... i did a compression test and from cylinders 1-6 were 145 to 150. so it isnt the cursed head. ive been told it may be my main and rod bearings. i plan on doing this job but i want a little bit more insight from someone with more experience before i get into a job like that with very low engine work experience. if i do end up doing the job i will be replacing the oil pump as well.


also i do have a minor low end whining noise which i assume is the bearings and a little bit of noise from a lifter.

[tech1001]

yes if you do all the crank bearings I would all so change the oil pump and the timing chain . What oil are you running ?

[Wayne Sihler]

Also tell us the oil pressure, cold idle and hot idle.
Normal hot idle with correct 10w-30 oil is 10>13 psi,No Fram filters ,please.

[RCP Phx]

4.0's like to eat cam bearings so that would be on my of things to do also.

[sidewaysstarion]

How sludgy is the inside of the motor? I wonder if your overheating it melted some of the sludge and now the oil pickup is restricted.

[md21722]

The heads on 2000-2001 4.0's typically crack between the #3 and #4 valves on the top of the head. This does NOT affect compression, but it does cause coolant to mix with the oil and contaminate the oil. The result is washed bearings and low oil pressure. Remove the oil filler cap and look straight down for coolant. Are you loosing coolant and is your oil milky colored?

[Michael20mac]

no coolant mix in the oil i changed the oil and filter the othr day after running some seafoam through. cold psi 40 at start. warm idle 0 highway speed 20 never over 20 after warmup.

replacing cam bearings would make me take apart the motor tim trying to avoid that right now.

im running 10w 30 no fram filters ive read about those.

[Michael20mac]

in the end i dont really want to take the motor out unless its getting replaced or rebuilt i dont have the funds for either right now.

[Michael20mac]

oil isnt milky its a golden brown as of the last change which was a few days ago.

[Michael20mac]

its the head i just checked its cracked.

[RCP Phx]

My 2k, the head didn't crack(but it was never tested) but it ate up the cam bearings in the mean time!

[Tim_MN]

Send a sample of the oil to www.blackstone-labs.com and they will advise if there is coolant in the oil.

[Heavyopp]

Originally Posted by Michael20mac

its the head i just checked its cracked.

Checked it how?

[Greenz]

There is a quick test lots of guys do at the JY before buying a used engine. The crackle test.

http://blog.parker.com/moisture-cont...-hydraulic-oil


There are two simple ways to determine on-site if engine oil or hydraulic fluid contains water:


1) Look at the system and if the fluid is milky in the area of the breather or fill cap/dipstick, more than likely there is moisture above the normal saturation point.


2) Use a simple crackle test to check for moisture in the lube or hydraulic system. Put a small amount of oil on a piece of tin foil, in a spoon or in a small metal container. Hold a small flame under the foil/spoon/container containing the fluid. If moisture is present then the fluid will crackle and pop as soon as it is heated up.

On-site analysis using the above methods will not determine the actual content of water, only if water is present. If actual water content is required, laboratory testing will be necessary.