2000 Jeep Cherokee Persistant Loss of Coolant

My son bought a 2000 Jeep Cherokee in New York. With a friend who also just graduated from college, they planned to drive the vehicle cross-country (we live in California.)

The friend’s mechanic checked out the car beforehand. It has 130K miles. It needed new U joints and tires (both of which were done). The oil was changed, the sale was made, insurance was obtained (‘insurance is expensive!’ wrote the new college grad – first post-graduate lesson learned).

They made it to Colorado, about one hour east of Denver, when the check engine light came on, and the temp gauge showed the engine was too hot. They stopped, let the car cool off for two hours, and made it to a mechanic.

The mechanic said, needs a new thermostat. So, $150 later, new fluid and thermostat, off they go. Camped between Boulder and Ft Collins, everything fine. Next day in Wyoming, same problem again. The overflow container was empty, and the radiator seemed empty. They read the owner’s manual, which said to make sure the radiator is free from bugs. They put more fluid in the radiator, used toothbrushes to clean the radiator, and away: everything seemed fine, but again in Salt Lake City, same problem.

So: what can it be? Jiffy Lube in SLC checked for leaks in radiator, found none (still my best guess). I’ve heard elevation can sometimes cause this, but that’s a wild ass guess.

Clues welcome.


i have a 1999 jeep cherokee that was running a little hot.change thermostat and water pump work great now.good luck,

If the water pump is external on this engine, you would see a visible coolant leak via the weep holes in the pump.

Short of this, I would suspect a leaking intake manifold gasket or possibly a leaking head gasket.

The reservoir loss of coolant tells me this. Unless of course, the reservoir has a leak.

Same answer I gave to another posting. Buy a new radiator cap. If the radiator cap doesn’t hold the system pressure the boiling point of coolant is too low, and it gets even lower as you go up in altitude, as your kids did. The coolant boils away, no obvious leaks because there are none, and the engine overheats. A new cap is cheap, easy to replace (when the engine is cold, please!) and often does the trick.

If I’m wrong you are only out a few dollars.

Well, the engine blew a rod in Salina, Utah. The water pump or simple radiator cap ideas were great, but now the question is: what to do with a car that cost $4000, which will cost over $3500 to repair? Just walk away?

I can’t begin to tell you my frustration with this whole situation.

The question here really is, hows the rest of the vehicle? My advice would be to check the mechanic files on this web site for a good mechanic in Salina, UT. Have the vehicle checked out for everything else. I know your son did this before buying the vehicle, but you really need a second opinion.

The engine should have lasted a lot longer that 130k miles, so it appears that the regular maintenance wasn’t performed on this vehicle. If the vehicle wasn’t otherwise abused, the rest of the vehicle maybe ok.

Putting another $3500 in it would be a good investment if he can get another 100k + out of it.

If the vehicle is otherwise in good condition and your son likes it, then a quality remanufactures engine, Jasper or Proformance engines are good, would be a good idea. If he abandons it (sell to junk yard) and buy another used car, he might get only as far as Reno and face the same situation.

The cooling system needs to be looked at thoroughly. This includes (and starts with) a pressure test of the system, a flow check of the radiator, a test of the water pump, and a test (or replacement) of the radiator cap. If the problem is unresolved at that point, tests for possibilities like a headgasket leak may be in order.

The good news is that cooling problems in a 9 year old vehicle are not that unusual and can usually be diagnosed and corrected using the basic protocols above.

Four points:
(1) DO NOT go to Jiffy Lube for this work.
(2) DO NOT GO to Jiffy Lube for this work.
(3) elevation is not the cause of the problem.
(4) Do not go to Jiffyy Lube for this work.

Thanks to all for your input.

He has chosen to repair the vehicle. Mechanic claims he can get new short block engine shipped down from Salt Lake, install for $2800 total (short block is $2100); not clear what’s included in the mechanic’s definition of ‘short block’, but it appears to include water pump; it had better include a ton of other stuff related to throwing the rod, or what’s the point.

The advice about 130K engine should’ve lasted longer is on-point. Won’t go into why; life-lesson for son (I hope).