Overheating: Determining if it is the pump or thermostat
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Joined: Jul 2012
Posts: 167
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From: The corner of Grey St.
Year: 1996
Model: Cherokee
Engine: 4.0L
Hi guys, I have recently replaced a head gasket and am dealing with an overheating issue. My understanding is that the coolant flow goes from the radiator to the lower hose to the pump through the block, thermostat, upper hose and back to the radiator. I have determined that it is either the pump or the thermostat. Does anyone know a way to diagnose which one it is? I assume that this overheating problem is what caused the gasket to fail in the first place.
Thanks,
Taylor
Thanks,
Taylor
Go buy a thermostat, new gasket, and small tube of RTV. If you take your time, and include the cost of a 6 pack, it'll take an hour and cost less than $25.
And you'll have a light buzz when your done if you drink fast enough.
And you'll have a light buzz when your done if you drink fast enough.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
The radiator is the only cooling system component that actually "cools" coolant. All of the other cooling system components mainly have to do with coolant flow. The radiator is the main component in the cooling system.....when overheating, suspect it 1st, not last.
Thread Starter
Member
Joined: Jul 2012
Posts: 167
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From: The corner of Grey St.
Year: 1996
Model: Cherokee
Engine: 4.0L
Thanks guys. Sorry, I should have added more detail. The top radiator hose is cool except for the closest part to the head. The lower hose is hot as well as the part of the radiator where it connects. The more I think about it I am thinking pump. I think the way to go is to replace both.
-Taylor
-Taylor
CF Veteran
Joined: Mar 2010
Posts: 47,923
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From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
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CF Veteran
Joined: Mar 2010
Posts: 47,923
Likes: 38
From: Broward County Fl.
Year: 1989 xj sport 2dr
Model: Cherokee
Engine: 12 hole bosch Injectors
Thanks guys. Sorry, I should have added more detail. The top radiator hose is cool except for the closest part to the head. The lower hose is hot as well as the part of the radiator where it connects. The more I think about it I am thinking pump. I think the way to go is to replace both.
-Taylor
-Taylor
Just had a similar issue in my 96. It would overheat at low speeds and idle.
I first flushed the system and replaced the t-stat. Didn't work. Then I replaced the water pump and fan clutch. worked.
Replace the t-stat with a fail safe version (if it fails, it fails open, rather than closed), and the water pump. It could be either but if you do both it's like 40 bucks. Not expensive or hard to do and well worth it.
I first flushed the system and replaced the t-stat. Didn't work. Then I replaced the water pump and fan clutch. worked.
Replace the t-stat with a fail safe version (if it fails, it fails open, rather than closed), and the water pump. It could be either but if you do both it's like 40 bucks. Not expensive or hard to do and well worth it.
CF Veteran
Joined: Nov 2009
Posts: 8,172
Likes: 17
From: The Republic of TEXAS
Year: 1998
Model: Cherokee
Engine: 4.0L HO
Here's an interesting read "Can a t-stat fail safely".
http://www.stant.com/Consumer-Produc...of-Thermostats

http://www.stant.com/Consumer-Produc...of-Thermostats
Thread Starter
Member
Joined: Jul 2012
Posts: 167
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From: The corner of Grey St.
Year: 1996
Model: Cherokee
Engine: 4.0L
Thanks for the help guys and thanks for the link. I was really interested about how one works. I liked the suggestion with the beer the best. haha I decided to go ahead and replace the thermostat because it was the cheaper option. As someone on a college budget price overrides the amount of labor involved.
Thanks again,
Taylor
Thanks again,
Taylor
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