2001 Jeep Cherokee - Overheating

Tiny
GATECH04
  • MEMBER
  • 2001 JEEP CHEROKEE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 122,390 MILES
Good Evening,

My 01 Jeep Grand Cherokee recently started overheating and I was hoping to find some help pinpointing the problem. Here is what Ive tried and what Ive looked for so far.

So far Ive replaced the radiator cap and thermostat - neither of which seemed to help. I even took the thermostat out all together and that didnt seem to work.

Here are my most recent observations from tonight (with thermostat still removed).

It took 6-7 minutes to reach a running temp of 210 just idling. Once there, it took only about a minute to get up near 260 when I turned it off.

While running, the large fan directly next to the serpentine belt was running continuously, but the smaller fan nearer the radiator never came on. I didnt try turning the AC though, I'll have to wait for it to cool down and I'll recheck that. I did try the heat while it was running though and only cool air came out.

After I turned it off, the upper radiator hose was very hot to the touch, the radiator cap was warm, the lower radiator hose was cool and both heater core lines were cool to the touch once you got far enough away from the thermostat (hence the lack of heat I assume).

When the engine is off, the large fan nearest the water pump only turns if I have consitent pressure on the blade and the smaller fan nearer the radiator "freewheels".

There are no apparent leaks (no coolant on the ground, no obvious leaks at the thermostat/pump/radiator/hoses/heater core).

Any help in narrowing down the problem would be greatly appreciated? Please let me know if you need more information of if I should snap some pictures.

Thank you
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Tuesday, August 11th, 2009 AT 5:55 PM

7 Replies

Tiny
OBXAUTOMEDIC
  • EXPERT
Hello,

I think you have given plenty of info.

It sounds like possibly your water pump.

Since you still have therm out remove rad cap and see if coolant is circulating.

The indication is that the upper hose gets hot and the heater and lower hoses don't.

Post findings.

.
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Tuesday, August 11th, 2009 AT 6:45 PM
Tiny
GATECH04
  • MEMBER
When I replaced the therm, I did run it with the radiator cap off for a bit with the new (presumably working) therm in - but Im honestly not sure if it was cycling.

It would bubble over a good bit, but occasionally suck down in - so I guess it was cycling some, but Im not sure if it was at a normal pace. I would assume some coolant would pass through the water pump even if it wasnt operating properly right?

I can check again, and report my findings. Also, the radiator rap/fill area is offset a little from the radiator, so I cant see directly down into it - I assume that wont affect the observation?

I dont mind changing out the water pump (actually it would be a first and sounds a little fun to me), I just dont want to waste $65 on a part if thats not it.

Thanks so much for the quick reply!
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Tuesday, August 11th, 2009 AT 7:19 PM
Tiny
GATECH04
  • MEMBER
OK I tried it out and made a video and uploaded it to youtube. I didnt let the engine even get to normal running temp, since a good bit of coolant was overflowing and I didnt want to make a toxic mess.

I did have the AC on full blast and the little aux. fan never came on, but the temperature never got to 210 either, so Im not sure if that is normal.

Anyways, here is the video -

http://www.youtube.com/watch?v=t_2IrMPnwwA

Thanks again for any help!
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Tuesday, August 11th, 2009 AT 7:59 PM
Tiny
GATECH04
  • MEMBER
Hope it's ok to bump. I think Im going to replace the water pump tomorrow night. Im still not sure thats it, but it seems to be the next step.

Can anyone watch the youtube video and verify if that's normal or not please?

Thank you!
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Wednesday, August 12th, 2009 AT 9:58 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Sorry for delay in getting back to you.

Anyway I watched the Video and that is pretty normal.

Let me know how the Water Pump went.

And results.

The only other cause that I can think of would be the Radiator being Clogged. If still overheating let cool down and open the drain on the radiator if nothing flows out then would need to remove lower hose and see if it is totally blocked. The only reason it would be is if there has been a lot of radiator stop leak put in it.

.
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Thursday, August 13th, 2009 AT 9:49 PM
Tiny
GATECH04
  • MEMBER
Thank you for the reply.

Unfortunately I havent had time to change out the water pump yet - it probably will be Monday or Tuesday before I have the time.

To my knowledge, stop leak has never been put in the radiator. We bought the Jeep used about 4 years ago and at that time it had under 40k miles on it. Since we've owned it there havent been any leaks. I'll keep an eye on it while draining it before I change out the water pump though. Depending on the cost of the flush kit, I may as well do that while I have the system drained. I'll probably replace my serpentine belt too. This might get expensive!
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Friday, August 14th, 2009 AT 6:50 AM
Tiny
OBXAUTOMEDIC
  • EXPERT
Well, since you will be doing the work it won't be as expensive as if you were to take it to a shop.
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Friday, August 14th, 2009 AT 4:55 PM

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