cherokee temp on the freeway ??

[mattvw65]

temp on the freeway ?? i have a 91 xj with the 4.0ho i have replaced the cooling system around town driving with the ac on it does fine regular operating temp but when driving on the freeway it gets hot??? any ideas?? im thinking the ac condenser needs to be changed (not letting air flow)

 

[Herzog]

could be the fan clutch going bad and slipping, not letting the engine fan get enough speed to get good air flow.

Dunno... XJ cooling systems is nothing more than a can of worms.

 

[Hickey]

take your hood off. that should help.

 

[Caleb]

couple other ideas, the belt could be slipping at higher RPMs and not spinning the WP (sufficiently) or some GM motors are known to do something similar to this but it is caused by a faulty WP and it aerates the coolant (basically it cavitates)...some other ideas?!?!?! I hate problems like this(when its my vehicles)...

 

[Hickey]

I had the belt proble with mine. I trid all kinds of things before I figured it outt.

 

[mattvw65]

the belt has a tensioner (self adj) i dont think it has an adjustment?

 

[Caleb]

Originally posted by mattvw65
the belt has a tensioner (self adj) i dont think it has an adjustment?

its should have the tensioner because its a serpentine belt...but if the belt gets any kind of fluid on it it could cause it to get dried out or if it is older then it could get dried out and either thing will cause slippage...plus check your tensioner and make sure that it is still working properly...sometimes they freeze up and will look like they are in the right position but they really aren;t applying much tension...

 

[Herzog]

Originally posted by mattvw65
the belt has a tensioner (self adj) i dont think it has an adjustment?

The adjustment is in the powersteering pump bracketry. You have to loosen 3 or 4 bolts on it before you can adjust it.

 

[Hickey]

oh yeah, Herzog is right. it is just an Idler pully on some and you adjust it at the steering pump.

 

[Brett]

Well, if you are on the freeway....and it's not staying cool....but it's stayin cool running around town......that's odd. Mine runs right at 180 all the time (thank you 3 core.) On the freeway it drops just slightly lower.

The only thing that I could think of for you is that perhaps you have air in your cooling system. Though, with the HO open system, that's not very likely.

I dunno!

 

[JoeT]

Same problem here and I've done the following:

3-core GDI
tranny cooler
Open system switch
180 t-stat
3 different clutch fans
Hood vent /scoop
HESCO water pump
Removed any fiberglass that was blocking the radiator behind the grill.

I'm just about ready to pull the head!!!!

 

[JF1]

Hey Matt, did you say that you replaced the cooling system? By this did you mean that you replaced the radiator? If not, it sounds exactly like you aren't getting enough fluid flowing through the radiator because it's clogged up. Take it out, reverse flush it and see how it does. Might as well replace the t-stat also if it's been awhile. Let me know if you need any help wrenching.

Joe

 

[RIGIDXJ]

I had that same problem until last week. I put out the money for a 3-core and now it sits at 190 all the time.

 

[harkinoff]

I had a similiar problem "gets hot only on freeway" it was the radiator fins blowing shut.. radiators do get old and fins begin to seperate, just an idea, happened to one of my old mustangs