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2001 Jeep Grand Cherokee - Overheating
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Gatech04
New User
Aug 13, 2009, 6:16 AM
Post #1 of 13
(22840 views)
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2001 Jeep Grand Cherokee - Overheating
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Good Afternoon,
My 01 Jeep Grand Cherokee recently started overheating and I was hoping to find some help pinpointing the problem. 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 the other night (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.
Here's a video I made of it running with the rad cap off. 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.
http://www.youtube.com/watch?v=t_2IrMPnwwA
Thank you
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Sidom
Veteran
/ Moderator
Aug 13, 2009, 7:36 AM
Post #2 of 13
(22826 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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On that problem I would probably be looking for a flow problem. With no t stat you should have circulation right away. I would take on the heater hoses off close to the water pump & see if the there is good flow off the pump. If you aren't getting a good stream, I would inspect the impeller on the water pump.
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Loren Champlain Sr
Veteran
/ Moderator
Aug 13, 2009, 9:41 AM
Post #3 of 13
(22822 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Pardon my jumping in;
Gatech04; Just watched the video. Is this with the thermostat in, or out? I believe that this engine has a clutch fan as well as an auxillary electric fan for the A/C operation? At temperature, the clutch fan should be 'locked up' and not freewheeling as you stated. I also saw air bubbles coming out of the radiator, indicating either air is still in the system from lack of 'bleeding' or is being put into the system from a head gasket leak which will cause overheating. With the type of 'neck' on the radiator, you may not be able to see if it is flowing coolant unless you lower the coolant level down to where you can see the cores, if at all. As Sidom stated, running it without a thermostat will cause overheating problems, so you don't want to do that, but it is a good test for checking flow. The thermostat is there for a couple of reasons. It keeps the engine at a specified temp (195F-210F is normal) and allows time for the water in the radiator to cool down before re-entering the engine when the stat opens.
Loren
SW Washington
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Loren Champlain Sr
Veteran
/ Moderator
Aug 14, 2009, 10:37 AM
Post #5 of 13
(22805 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Gatech; How did your cooling system look before you drained and filled? Was it very rusty? Not that it matters much, now, but I'm thinking of the water pump impeller as Sidom had mentioned. If the system was very rusty, it is possible that the impeller has rusted away enough to affect flow. It is very rare, but I've also seen the impeller come loose from the hub. (originally, pressed on) Another thing is a plugged radiator. For the following tests, drain and save your anti-freeze so you can re-use it. Fill the radiator with water. Remove the lower radiator hose. The water should gush out. Using a garden hose, you shouldn't be able to keep up with the water flowing out of the bottom of the radiator. Another test, although may be hard to do, at normal operating temperature, feel the radiator with your hand. The temperature should be equal, throughout. If you feel a spot that is cool, then it is plugged. With the thermostat still out and the engine idling and cold, remove the upper radiator hose. Careful that you don't get a bath. It should shoot water out like a firehose. Of course, only run it for a few seconds to watch the flow from the water pump. If you didn't know, cold water from the radiator goes into the water pump, then throughout the engine, then back into the radiator through the upper radiator hose past the thermostat when it opens. So, it's normal for the lower hose to be cool and the upper hose to be hot.
Now, back to the head gasket issue. Head gaskets generally will blow into an exhaust port, rather than into the crankcase. So, pretty common to see a blown head gasket with no water in the oil. This is an easy test. Either with a chemical, available from most parts stores, or with an exhaust gas analyzer which any shop that does emission repairs, will have. That's actually where I'd start, first. Eliminating, or confirming, the head gasket.
Loren
SW Washington
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Guest
Anonymous Poster
Aug 14, 2009, 12:41 PM
Post #6 of 13
(22801 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Thank you for the reply!
I actually havent drained the system yet. I lost some coolant each of the 2 times I overheated on the road due to the hot coolant overfilling the resevoir and spilling out the overflow until everything cooled down.
When I changed the thermostat and subsequently removed it again, I just let the coolant/water fall as I was on the side of the road (I know - bad).
I'll be sure to do the radiator tests you mentioned on monday when I drain the radiator. I'll probably pick up the exhaust test tomorrow though to clear that issue.
I'll try to take pictures and videos throughout the processes so those smarter than I in these areas can keep me on track!
Thanks again for all the help!
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Gatech04
New User
Aug 14, 2009, 12:45 PM
Post #7 of 13
(22799 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Looks like I forgot to log in (came here via link in update email) but that last reply was me!
I think this will be my tentative process from here:
1) Check exhaust
2) Drain Radiator
3) Fill with water
4) Perform flow test at bottom rad hose
5) Perform flow test at upper rad hose
6) Remove water pump and inspect for damaged impeller
7) .... Fix it!
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Loren Champlain Sr
Veteran
/ Moderator
Aug 14, 2009, 12:57 PM
Post #8 of 13
(22797 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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You'll get it! Let us know how it goes.
Loren
SW Washington
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Sidom
Veteran
/ Moderator
Aug 14, 2009, 1:11 PM
Post #9 of 13
(22797 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Im not real sure what this means. Should I take the hose that goes from the thermostat housing to the heater core off, then turn on the engine (without the thermostat in) and see if coolant is being pumped through the hose (to the heater core). If not, that would indicate a bad impeller.
Yes, you're just looking to see if the pump is capable of genrating some good flow. Im memory serves me correct (which ½ the time is don't) there is a steel tube coming off the pump for the heater hose, you could use that line, or Loren's suggestion of the upper hose, either will work & either will make a heck of mess if the pump is good, so prepare accordingly. Impellers problems are definately the less common ones and I wouldn't change the pump "just because" but if you aren't getting any flow off the pump, that's problem.... The a boroscope would be nice, but I don't imagine you have on of those.....
Loren has given some real good steps to find the prob...... I would probably follow those 1st.........
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Gatech04
New User
Aug 27, 2009, 3:36 AM
Post #10 of 13
(22767 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Well I finally had time to work on it again Tuesday night. Turns out the plastic impeller had broken loose from the shaft. I got it fixed and put back together, added a new serp. belt and flushed the radiator. Everything is working great now!
Thanks for all the help!
GT
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Sidom
Veteran
/ Moderator
Aug 28, 2009, 3:15 PM
Post #11 of 13
(22754 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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Glad to hear you found and fixed the problem.....good job........ Thx 4 coming backing with the results to your problem........ You may help someone in the future......
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lovemyjeeps
New User
Sep 26, 2012, 2:42 PM
Post #12 of 13
(17007 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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I have the same problem described here on my 2001 Cherokee Classic. I just did the upper radiator hose test and only got steam even as temp reached 210. Any sugestions?
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 26, 2012, 3:41 PM
Post #13 of 13
(17004 views)
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Re: 2001 Jeep Grand Cherokee - Overheating
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You need to start your own thread please.
Read this on how to create a thread:
http://autoforums.carjunky.com/...ORE_POSTING_P122997/
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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