Heavy Duty Cooling System

Is the cooling system on Cherokees w/ the regular pully powered fan + the electric fan that comes on at a certain temp considered the HD cooling system? Im just curious because my 2000 XJ has this. Thanks so much.

fdsa487 said:

Is the cooling system on Cherokees w/ the regular pully powered fan + the electric fan that comes on at a certain temp considered the HD cooling system? Im just curious because my 2000 XJ has this. Thanks so much.

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Nope, that's sounds like what's on most every other XJ out there.

Daryl

It used to be years ago you could order a heavy duty cooling system and it was actually a different thicker radiator. That option pretty much vanished in the mid to late 80's. It is possible that the police package *might* have a different radiator but I doubt it. What you have is pretty much stock like every other XJ out there from the factory.

So RichP, does that mean that every XJ came with a Tranny cooler in front of the Radiator?

I would not know, I've not owned an auto tranny since 75. I *think* the tranny cooler only came on the towing package. The only thing on my 98 in front of the tranny is an evaporator for my AC, same with both our TJ's... Usually the way it has worked in the past is that you could order a HD cooling option if you did not order A/c or it came with it if you got A/C. I seem to remember some pre 95 owners who either had 2.5 or maby 4.0 that had single core rads while the ones with A/C, Upcountry or towing had two core ones..

sjx40250 said:

So does that mean that every XJ came with a Tranny cooler in front of the Radiator?

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Maybe with the tow package. But most only have the one built into the radiator.

Daryl

An external cooler is usually part of a "HD" cooling package - mainly because it's a component that removes a thermal load from the engine cooling loop.

If you want to go heavier, you can get a 3-core Modine pretty easily, and they work very well. Include a high-volume water pump and you've got a chance to get a little ahead.

The AUX fan has two "trips" OEM - the thermal fan switch (that is, I think, in the ECU by then) and the A/C Request signal when you turn it on. I'd have to look at the wiring plans, but it should not be too difficult to put an override switch into the system so you can also turn the electric fan on at will. It's easier on RENIX, since it's on its own circuit. For the later models, I'd look for an easy way to trip the fan relay with a toggle switch - that works with a minimum of additional circuitry...

5-90

I concurr with 5-90. I purchased my 90 new and it had a HD cooling system included as part of the tow package. The cooler in front of the rad is not in place of the cooler in the rad, it is in addition to it and I believe it is in series after the rad.

to simplify the wiring xj armor (search for them many posts) has a fan overide kit that allows manual use of the fan instead of the computer thermostat... a good option that makes use of the stock electric fan instead of re-installing a new unit... also works with the computer when not trigged to run when the temperature reaches the certain degree....on my 99 xj that is close to 210 but after my 3 core rad, fan override kit, high flow stat housing, tranny cooler, oil cooler and hood vents this temp is never reached in the summer with the electric fan on full time with all my other mods...any ways a good investment for the fan kit... about 40 bucks total...also some other thing i have seen on ebay but this one worked for me...be wary of other items and customer sefvice though with xj armor as you can see clearly from other posts...this is the only item i have ordered from them.

http://www.xj-armor.com/electronics.htm

sjx40250 said:

No. I believe the HD cooling system includes the tranny cooler in front of the Rad. There is a "cooler" for the tranny in the Radiator output tank as standard and with the HD.

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No, the external tranny cooler is just that -- it's an external tranny cooler. It has nothing to do with the heavy-duty-ness of the cooling system.

In general, if the vehicle has either a tow package or air conditioning it has heavy-duty cooling. The auxiliary electric fan is part of that package. It is possible to have an XJ with heavy duty cooling but no external tranny cooler, and in fact an external tranny cooler would be impossible with a 5-speed. And it was possible to buy an XJ without a/c or tow package, and when so (not) equipped they came without an auxiliary electric fan.