To start off; I have a 2000 Jeep Cherokee classic with the 4.0 I6, with 130,000 miles, and I'm very aware of the 2000 model year head casting issues between cylinders 3 and 4, and I have not pulled the valve cover YET to verify if there is in fact a crack. But from all other ways to tell, i do not have a coolant leak anywhere internal or external. no antifreeze in oil or steam from the tail pipe. once every week or two weeks i have to add almost a gallon of antifreeze. I am stumped. my main concern is my oil cap has a milky substance from what i think is condensation.
Also there is some sort of stop leak in the cooling system from the p.o.
Any ideas or advice would be greatly appreciated.
Thanks in advance,
Change your oil and see if you have mocha colored oil. With that much fluid in it you should see some leak from the rear main if head is cracked. Honestly you may not even notice the crack if you don't know what to look for. Mine was very difficult to see.
That's the crack in mine. Because it was a small leak I never developed the milky cap. Mine looked like miles of rust in radiator. Odd thing is she ran very good.
it is what it is except when its something else
All your symptoms are pointing to a cracked head. Measure your oil when drain it next time and you'll see some of the missing coolant. Replace the head before putting any more miles on the engine. The antifreeze will toast the lower end bearings faster than you think...
For what it's worth, for a period of a few months, I did a lot of short trips in my Cherokee. Ranging from hot days to damp days to freezing winter days. Never once did I get a milkshake on the oil cap. Some vehicles, by nature, will get the milky oil cap (ford's mod v8s) ... jeep 4.0s generally won't get it with short trips.
And, if they run hot enough, that they'll burn off any normal moisture as soon as they heat up.
2000 XJ - 3.5'' Lift & Skinny Mudders.
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it is quite difficult to spot, its a very cramped area. you might be able to smell it but it usually blends in with other smells that come from you motor. I found mine using a flashlight and one of those little mirror-on-a-stick that dentists use. but if you're losing a large amount of fluid, then you should notice it on the garage floor.
you have a cracked head. Brothers 2000 xj had the same symptoms. Using coolant, no leaks and still ran great. Replaced the head and it hasnt used coolant at all. Caught it quick enough. bite the bullet and replace your head
I do work for orielly auto parts, so the head will only run me about $370 + head bolt set $35 + head gasket set $100 +/-. Now i haven't pulled the valve cover yet, and my jeep is a late 2000 model year i think. So if i just happen to have the (0331) casting; then what else could it be?