My 1990 cherokee 4.0 when i first bought it was great. But for the past year ive been dealing with the overheating nightmire. When im in stop and go traffic or just doing some around-town driveing the temp just shoots up. and if i let it just sit there and idle it will just overheat and blow coolant out of the overflow resavor. Ive replaced the over flow resevor, thermostat, resevor cap, water pump, fan relay sensor, and ive had the system flushed. Im getting so sick of dealing with this problem. Ive heard that this cooling system in this year is terrible. Does anyone know how i can change it to an open cooling system? and if i do that will i see results? and not have to deal with the overheating problem anymore. PLEASE helpp!
thanks

 

the electeric fan may not be working or the conections may be loose or bad relay

 

Dude, been down this road like a hundred million times. My 90 was bad, very bad about over heating. I ended up changing the overflow bottle to one with a cap and it helped for a while, but you really need to switch to a radiator with a cap from a 93. I bought a new radiator from theXJfiles on the site for a killer deal. My dad and I put it on, and now I can't even get it to 210, even if I am really hard on it. There is a really good write about it on the site. Do a search.

No other way around it.

Trev

 

why did you post this to day if u'd allready fixed it

 

Fixed it? nothing is fixed...thats why im asking how to change it to a open cooling system...and if i do, will it work.

 

o' srry i cant help u i have a 97 with alreadly with it good luck though

 

r u haveing trouble with ur speedometer? cause u know i am

 

Not fixed

 

If it overheats at idle but not when you're driving down the highway, those are the symptoms of a bad viscous fan clutch. That's the piece behind the mechanical fan that allows the fan to freewheel when it's not needed, like when you're running down the highway. If it fails, it also freewheels when it is needed in traffic.

A new one costs about $35 and is not a hugely difficult replacement. There is no reliable test for it that does not include taking it off the vehicle, and by the time you've done that you might as well just install a new one instead of putting the old one back on. It really should be included in a cooling system overhaul, but people often neglect it.