I have a 1999 Cherokee 4.0, I have replaced the water pump, thermostat and flush the radiator several times as long as I ride in town --stop and go its ok BUT when I get in the woods and go real real slow it gets hot..
WHAT could be the problem??????
Thanks for any help..
OL Man
Walt

 

Fan Clutch? Electric Fan working properly?

 

Fan shroud intact/in place? How old is the rad? Regular cooling system maintenance? Crud, that won't flush out, can build up inside a rad drastically reducing the rads ability to dissipate heat.

 

I have electric fans and they are working --New rad. cap. and hoses . Guess I will replace the rad. Friday.
Thanks for the info

 

Did you purge the air out this similar thing happened to me although not in my xj it happened in my 70 Chevy when I rebuilt the engine I forgot to purge the air out and air pockets would make it spike up from 160 normal to 220 in about a minute randomly. I purged the air out and never happened again. Hopefuly your head isn't cracked....

 

Other then the thing the others have mentioned are you sure that the electric fan are capable of pulling the right amount of SCFM required to keep the engine cool at the low speed? Many of the electric fans off the shelf don't pull enough SCFM's needed.

 

Yep, I'd suspect the efans. Got any specs on the efans?

 

No info on the 2 fans....what cfm should they be?

 

The OE factory efan moves something like 2300 CFM. The OE factory belt fan will move way more than the OE efan at just above idle speed, presuming a good fan clutch. I'd say CFM of both fans would be well north of 4000 CFM. The OE factory rad fans are not the weak link in the XJ cooling system.....it's the dinky radiator.

 

I believe the mechanical fan with a new clutch in our XJs was measured on its ownupwards of 5000 CFM...

 

Sorry should have said that some one put 2 EFans on...No info on the fans.The top rad.hose is hot while the bottom is luke warm...air flow thru the fans seems ok...It will sit and Idle all day at 210-212,

 

I'm going to side with the guys saying not enough air flow. I know when my fan clutch wasn't working at 100% (rest of cooling system was fine) I had no overheating problems at idle. But put a load on the engine (increase rpms) such as crawling around the backroads or offroad or pulling a long grade up a mountain and it would rise to the red on the gauge. New fan clutch resolved the issue.

 

That is why I very rarely if ever suggest to replace any mechanical fan with an elect. set up. Unless you are 100% sure that they put out at least what is required SCFM or more if possible. I have seen many people do it and regretted it. I also did it when I had my first car(when I was 16) to get more horspower. But it was a waste because of the over heating problem.

 

Yup gotta get good fans that push a lot of cfm. Like Spal fans I have one single 16 inch with a shroud on a 480 horse small block Chevy then if course I have a all aluminum 3 core radiator. And a huge grill. Lol these cherokees have tiny radiators.

 

I've never seen any posts showing CFM numbers regarding the belt fan, so that's good info to know. Wonder what RPM made 5000 CFM? There were test numbers posted over at JeepForum.com regarding the OE factory efan (2300 CFM). Since the belt fan is obviously variable speed, CFM numbers will vary also. I just know that using my hands to feel the air being pulled/pushed by the 2 OE factory fans (highly scientific, I know), the air flow from the OE belt fan, at just above idle rpm, is way more than the OE efan. That's why I always recommend doing one's homework/research when it comes to modding the OE factory rad fan set-up.

The 10" Dirt Bound efan is the closest I've seen to the OE efan's CFM.....and those come in sets of 3 fans, not 2 fans.