Faol

My 1994 XJ Country is still overheating. I have 189,000 miles on it, and it is not abused.

On the advice of a mechanic following the XJ starting to overheat (getting above 210 all of the sudden), I changed the head (head and full gasket set = $300.47 w/ tax). I also changed subsequent gaskets that came with kit, thermostat (fail safe), temp sensor, temp sender, heater valve control, all coolant hoses, had the radiator tested (after market aluminum 3 core), new trans cooler lines and tune-up kit, engine tune-up, PCV and breather valves, oil filler cap, and radiator cap.

I put it all back together and I still have the same problem. It will get above 210 in about 10 or 15 minutes of just sitting and idling. It started doing that a couple of weeks ago when I driving to a larger town. When I would get into town, or at a traffic light, it would get at 210, or slightly above, but being in the country, it wasn't long and I would be able to drive again. At which point, it would cool back down.

I am not sure if this is a symptom, but when I have the radiator cap off, trying to burp the system, the fluid flows out of the filler cap when I turn on the heater, continuously.

The aux fan comes on when I unplug the temp sensor, or turn on the AC, but it doesn't come on as it is overheating. I know it used to come on in the winter, when left idling to warm up. I changed the relay, but nothing changed.

I had to buy additional tools to do all this, so my total spent so far is about $1,500. Head gasket repair quotes were anywhere from $1,250 to $1,500. I reckon I am ahead of their deal, but I am still not fixed, so paying them would have been a waste too. My daughter said, "at least you will be good for another hundred thousand." I can only hope....after I figure out what is going on.

Any suggestions?

captainofiron

did you change the temperature sender that is located on the back end of the head on the intake side?

UserID6095

I didnt see water pump on your list.

Too burp the system the rad needs to be higher then the engine. Try parking or jacking the front end up to get the rad cap as the highest point in the system.

Faol

I sure did. I replaced it prior to doing the head.

Faol

No, I didn't replace the water pump. We checked it when I had everything broken down for the head installation, but there was no play in it, nor rattling.

I also have not replaced the clutch fan.

Aren't these two items about the only thing left to the cooling system that could cause overheating? When is the aux fan supposed to cycle on, because that isn't working either.

Faol

Would air make the fluid just roll out of the rad cap?

mrbitz

I have a '95 Cherokee that has had an over heating problem before. My problem was with the switch that tells the Aux fan to turn on. I understand (my memory may not be perfect on this) the Aux fan should ALWAYS come on when you turn on the AC. I know when I was having problem in took not more then 15 minutes to overheat if it was warm out. I'm in Oregon so warm is 80 degrees to me. Normally if it was 80 or warmer it would overheat VERY quickly. If, when it is overheating, the AUX fan is not on then that would definitly be related to the problem.

captainofiron

ok because some people dont know about that one in the back and only replace the front fan controlling sensor thats in the thermo housing

fan clutch is a big one, I would do that, usually when my Jeep overheats its the fan clutch or a compromised hose

captainofiron

if the radiator is higher than the engine, no

what I have done to get the air out of my coolant system, is I split the feed heater hose, and put a Tee fitting in there to backflush the coolant system, so when I do work on the system, I take off one side of the hose, and I stand the hoses straight up, and fill it that way, and while filling, I squeeze the hoses until the air bubbles come out, usually for my jeep its the upper hose that gets bubble

huntingman2706217

fan clutch... it might be spinning but that dont mean jack... if its bad it should also have some play front to back... if it overheats sittin and not when you driving then its got something to do with a fan... OR theres mud in the fins (not on the inside) keep air from blowing through...

huntingman2706217

and ive yet to see a air bubble make a engine overheat... but thats just my experiance (prior Nissan tech)

new1999cherokee

My cherokee does the same thing and has for years - I just got a new engine - water pump - all hoses and still goes above 210 at idle - it's normal i guess

96xjcountry

The fins will rot off of the water pump inside, seen that from prior experience.

duncan0668

My daughters Volvo, she drove during her collage years. started overheating when the AC was on. I had the radiator rebuilt, repaced water pump even though the aux fan worked it would still overheat duing long idle or when AC was on. I finally replaced the fan clutch and problem solved. Any time now I have a overheating problem the fan clutch is the first thing replaced. I doesnt matter if its a Jeep or a Volvo and later a Corvette No air movement no cooling.

Faol

Here is an interesting change. I noticed when the xj would get to overheating, the coolant was cold...in all lines, including heater. Sticking your finger in the radiator would yield cold coolant. Not warm...COLD.

Revved up the engine, between 2500 and 3000, and it all of the sudden started dropping. Stabilized at 210, but the aux fan is still not coming on. It does cycle on and off when the AC is running though, just not when the heater is on. I need to get another couple of quarts of Dex III, and then I will take it for a spin to see how it works.

Also, here is a new twist. All attempts at changing vents and such yield only air flow through my defrost vents. AC or heater does not matter. No change. WTH??? I didn't mess with anything inside.