Jeep Strokers

I have a 4.6 liter I6 stroker in my 91 Jeep Cherokee. The cooling system is just not able to keep up.
These are the changes I have made.

1) Changed the aux fan to the 10 blade newer model
2) put in a 3 core radiator

With the A/C on and air temps at 90 degrees here at 7000 ft altitude. I get coolant temps around 225 degrees even at highway speeds around 70mph.
I have read everything I can find about Cherokee engine cooling but for every article claiming cooling gains there seem to be two which claim no cooling gain for every modification I can find. I plan to try these two things next.

1) external B&M transmission oil cooler (get the tranny oil lines out of the radiator) It seems to me that this mod still has the heat transfer all in the same loop but many claim it helps.
2) Hood louvers on either side of the hood near the rear of the engine bay.

Does anyone know definitively whether or not a Flow Kooler high flow water pump will lower coolant temperatures in a Jeep cherokee cooling system?

This sounds like general tech so i moved it..


Have you replaced your fan clutch? Sounds like the culprit right there...

Also, a 3 row on these vehicles may do more harm than good. a 2 row is preferred.

I have replaced the fan clutch and I've seen lots of different opinions about what the best radiator is. I can't find anything conclusive regarding a radiator other than "more frontal area is better." Is there any larger radiator which would fit in an XJ?

foggybottombob wrote:These are the changes I have made.

1) Changed the aux fan to the 10 blade newer model
2) put in a 3 core radiator

With the A/C on and air temps at 90 degrees here at 7000 ft altitude. I get coolant temps around 225 degrees even at highway speeds around 70mph.

The maximum I see my gauge go to is 215*F and that's driving at 80mph on the highway in 110+*F heat with the AC on. In cooler conditions and with the AC off, the engine stays at 180. My cooling system combo is OEM 2-row radiator, dual electric fans (aux fan is newer model), Flowkooler water pump (definitely helps when engine under load), and Robertshaw 180* t'stat.
In your case I think the 3-row radiator is hurting you. I also had a newish 3-row radiator until last year and I wasn't happy with it. When I swapped a new OEM radiator in, the engine ran at least 10*F cooler so I suggest you do the same.
At 70mph it won't make any difference even if both fans don't work. A fan problem is only going to make the engine run hot at slow road speeds or idle.

I'm certain that the radiator is the most important element here. I've read some comments about aluminum radiators having better heat transfer characteristics but I've also experienced a lot of leaky aluminum radiators over my life time. So I don't know whether or not to take a chance on an aluminum radiator. Does anyone have any experience with the aluminum vs brass radiator comparison?

I just drove the XJ down town and the overheating problem is definitely mostly associated with sitting still at a light. Evidently the fans are just not adequate.

I just found a local 4WD shop who will put a Taurus fan on my XJ for $200. I already have all the parts so I'm going to try this mod first and see if that will be enough before doing anything else.

I have a CSF 2 row rad, balanced t-stat, high flow t-stat housing, and hood vents. It keeps mine around 210* even sitting in traffic. I tried a flow kooler pump on the stock engine a while ago. With both the stock rad and CSF it made it run hot on the highway. I didn't scientifically test it but I think its from the water flowing too fast through the radiator. I do want to see how another stock e-fan would work though.

Sounds like a 2 row radiator may be a better choice than a 3 row although this is not intuitive to me.

It has to do with surface area and flow. The 3 row has small tubes therefore less flow and less surface area from the tubes themselves.

Go buy a bottle of RedLine's Water Wetter.
Dump it in.
Note the drop in your operating temperature (typically 5-10*F - which is plenty!)

I've never much cared for the 212-215*F operating temperature myself...

+1 on the water wetter . works!! brought my cooper down 10* . also the seperate tranny cooler sounds good , but where to put it? you could remote mount with it's own fan ,. also has anyone done header coating or even header wrap to lower under hood temps ? hurts cats eventually but it gets under hood temps down .
might even help with number 6 lean condition some suspect .

Header wrapping is nasty stuff i'd steer clear of it. Ceramic coating is an idea to reduce under bonnet temps... if you can be arsed removing the headers to go and get them coated. I'd sooner put hood vents.. like these: http://www.genright.com/ProductInfo.asp ... id=LVR1009 and i like the look of these but only on the XJ http://www.hoodlouvers.com/jeeps.html. The former i think will be my choice for my TJ

Here is what I did. Hood vent fixed my overheating problem.

I have a pair of these vents but have not put them in yet. I just bought some water wetter and will be adding that to the radiator today.

http://www.reactionresearch.com/hoodvents.html