• Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Losing coolant

C

chrisser

NAXJA Forum User
Location
Spencer WV
01 XJ AT with 4.0

Losing coolant every few weeks. Trying to diagnose.

Pressure tested it today and it held 15psi for most of the afternoon. No visible leaking I can find.

Oil level hasn't risen and oil looks OK.

I had to drive it to take the garbage out so it's currently hot. Planning on taking the plugs out tonight once it cools down and pressurizing it again. Going to look at the plugs and listen for hissing and maybe drag out the bore camera to see if there's any coolant dripping in. Also plan on pulling the valve cover and checking for signs of cracking (believe it has the original head).

Also going to remove the lower engine cover to get a better look at the underside.

If you have any other suggestions while I have it partially apart, I'd sure appreciate them. I have a few other things to take care of so I planned on it being down for a coupla days.
 
If there is no obvious leak from the cooling system, then the likely causes are a leaking heater core or a cracked head. If the heater core is leaking, you'll smell coolant in the passenger compartment.
 
I haven't seen your pressure test setup, but if it is like mine it connects at the radiator cap, to the exclusion of the overflow line and overflow bottle. I had a situation where the leak was at the overflow line where it connected to the top of the radiator. Pressure test would not find it. I had to get lucky checking things right after a drive.
 
maxbraketorque said:
If there is no obvious leak from the cooling system, then the likely causes are a leaking heater core or a cracked head. If the heater core is leaking, you'll smell coolant in the passenger compartment.
Click to expand...

I lost my sense of smell, but I checked the carpet and there's no sign of leakage on the passenger side. Would it be worth pulling the blower motor or is that the evaporator just inside the cavity?
 
Anak said:
I haven't seen your pressure test setup, but if it is like mine it connects at the radiator cap, to the exclusion of the overflow line and overflow bottle. I had a situation where the leak was at the overflow line where it connected to the top of the radiator. Pressure test would not find it. I had to get lucky checking things right after a drive.
Click to expand...

Interesting. Yes, mine plugs the hole into the radiator but doesn't pressurize the area where the coolant overflow hooks up. Worth checking that line.
 
I've been dealing a little with this and found coolant coming out of the radiator cap on Sunday when I was trying to find a leaking brake line. I put an old cap on and will be monitoring it. I'll assume you already ruled the cap out? Since it's an 01 I figured I'd put this link here too just in case it's the head:

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

I had a 95 cavalier back in the day with a leak in the aluminum head. It was extremely difficult to see where it was coming from and very conditional regarding temperature and when/if it leaked.
 
Really annoying that you can't edit posts but anyway... I forgot to add...I dealt with this on a 99 in the past and as already mentioned, the heater core may be the culprit too. In this case it was coolant loss and certain mornings a very slight condensation spot on the windshield. It would be dripping right below the dash to the right of the transmission tunnel on the passenger side.
 
You need to put some dye in the antifreeze, that will show you where the leak is if it's on the outside! Make sure to check all the freeze plugs specially the hard to see one at the rear of the head.
 
01 with the original head? Likely cracked.

I had the mystery coolant loss on my 01. Only other issue with the engine was the heat soak on a hot restart. Never really gave me any running issues. No coolant in the oil. Seemed to just evaporate off or maybe end up in the cylinder/exhaust

You may be able to see coolant wicking out through the crack when you take off the oil cap while running as the area the 0331 cracks is right there. I replaced mine with a TUPY and no more coolant loss issues.
 
Yep. The head's cracked.

After sitting all night pressurized, I can see the crack on top of the head. I suspect it's also cracked below.

Thanks for the help, guys.
 
Russ P has a replacement head that he really likes/uses now!
 
Picked up a used head on ebay off an 04. After some cleaning and replacing the valve seals, got it installed.

However, while rotating the engine after installing the first few sets of rockers, noticed an odd noise. Determined it was a sloppy timing chain. So now I'm working on getting the timing cover off to replace that, which works out since most of the stuff needed to get there is already removed.

I new the front crank seal was leaking, so fixing that is a bonus, but I also discovered the cover itself was leaking because three of the little screws were not even finger tight. I don't know if a previous owner was responsible or if it came out of the factory like that. Timing cover is the only part of the engine I haven't been inside yet, so it wasn't me...

Should have it all back together in a day or two.

That one head bolt under the cowl is really fun ��.
 
Note that under the timing cover there is a little piece they call a "snubber" (IIRC). It is a thick piece of rubber which will have turned into brittle plastic by now. Odds are it will be broken when you get in there. While you are gathering parts you probably want to get that piece too.
 
Anak said:
Note that under the timing cover there is a little piece they call a "snubber" (IIRC). It is a thick piece of rubber which will have turned into brittle plastic by now. Odds are it will be broken when you get in there. While you are gathering parts you probably want to get that piece too.
Click to expand...

Thanks for the tip. Used to be I could get just about anything for the Cherokee at the local Advance or in the next closest one.

I have to drive 45 miles away to get that snubber.

Getting crazy out there.
 
Parts seem to be more of a PITA than ever.

I ordered one of those snubbers for Varmint #1's XJ a month or so ago. Rock Auto sent me the correct box, but inside was some part for some GM 4 banger. I had to get Rock Auto to try again. It would have sucked if I had not been planning a long way ahead (we still haven't gotten to that particular job on his XJ).
 
You must log in or register to reply here.

Similar threads

O
0331 Strikes Again...?
Replies
11
Views
311
Ol Blue
O
I
2000 Cherokee XJ Misfire Mystery
Replies
12
Views
210
Tim_MN
Tim_MN
J
2001 4.0L issues
Replies
15
Views
280
Saudade
Saudade
R
Tips on lubricating the hood hinges?
Replies
6
Views
118
Rob Mayercik
R
V
High temp woes
2
Replies
21
Views
428
Vitzaa
V
Back
Top