Hey Guys- As I begin familiarizing myself with my new Jeep wanted to ask what the symptoms might be of this issue that seems to plague 2000 and 2001 XJ's. Mine seems pretty decently cared for with 161k on the clock, but want to be as aware as possible about this issue and to get it rectified ASAP if I see it coming. I have a few mechanical issues to work with (transfer case doesn't always disengage 4x4 in a timely manner) but want to be as on top of this as possible.

Thanks for any and all advice!

`Rick

 

It will start loosing coolant and the coolant will go into the oil and if you look under the oil cap at the head that is where the head will crack and you should see coolant leaking . My 2001 has 165K on it and no problems with the head , all though I did rebuild the cooling system .

 

Thanks Tech_ I didn't see anything suspect under the oil fill cap, but will change the oil in the morning to see how it looks. Thanks!

 

you can send you oil off to get tested. The test will show if there is coolant mixed in. For mine, the coolant missing started off slow. I noticed it was low, so I kept checking it. Every once in a while I would add coolant. Then it kept getting more frequent, until it got to the point I was adding a half a gallon every 30 miles. My coolant never looked milky. I've since replaced the head and have had no issues. Going on a year and a half with a new head.

https://www.blackstone-labs.com/

 

Thanks Mikesignal- so the fact that the coolant is old and brown from what I can see in the radiator should be a warning sign or just neglected coolant flushes?

 

Could be either, or both. Usually oil will swirl at the top of the radiator. When it's cold, check under the rad cap. You can do a test for gases also. The rent a tester at the auto parts store. I think it's called an antifreeze HC tester.

 

Checking the level in your coolant reservoir Rick, should now be something that you do every WEEK. Because if you are subject to a cracked 0331 cylinder head, unless you get on it early, coolant will mix with the oil and that will trash your engine bearings and then you are looking at a rebuild or replacement of the engine.

As for the brown coolant, unless you are actually having to add coolant, it likely is simply from the coolant not being flushed/replaced enough.

If you are not having to add coolant, I would suggest doing a thorough cleaning of your cooling system, replace with a 50-50 mix of regular green antifreeze and distilled water, let the system burp out over a few heat up / cool down cycles and then watch that coolant level.

If there is any question, as mentioned by Mike, you can go to your local parts store and ask them for a "block test" which samples the gasses in your cooling system for the presence of hydrocarbons (which shouldn't be there). Napa for sure has these test kits for around $35.

When evaluating the cooling system, consider a wholesale replacement of all hoses (they can rot from the inside out too) as well as radiator cap, thermostat.

The money spent on your cooling system is possibly the best money you can ever spend on your XJ!

Good luck and keep us updated!

 

TJ- Thanks for the advice! I will do a thorough flush this week. Appreciate it.

 

If oil and coolant mixes you will literally see a chocolate milk residue under the cap usually. You can also get a kit from a part store to check the coolant for gases from combustion.

Not necessary to send in your oil.