Radiator upgrade for the 2.5?

Side by side, I can see a lot of difference in core supports between a four cylinder truck and a six. In my mind, I imagine the four cylinder supports unbolt, making way for the longer radiator and core supports for the 4.0, but what then with the fan shroud, or the presently non existent electric fan?

Should I just look for another radiator that bolts in?

The 4.0L rad should be plug n pray for the most part. The non-AC 4.0L XJ's only have the offset mech fan, and no e-fan. You could possibly run a dual/triple e-fan setup.
Not sure if it was naxja, comanche club or another forum. But I do remember recently seeing something about 4,0L rad swap.
I guess you could always keep your existing mech fan and build/modify a shroud to fit.

So replace the fan studs with short bolts, and run one or two electric fans from whatever looks close enough in the salvage yard? I've been through many a fan in the four door, busted one pulling out of an alley once, so "period correct" xj fans are out. It's a wonder the last one is still in there.

This truck does have AC, but the little radiator lacks the space for an auxiliary. Should I find electric fan circuits in the harness, or at the fuse block? Something I'll need to add myself? Where would I get the signal for the relay, in that case?

Why do you need a different setup than stock? A fully functioning stock cooling system should be more than adequate to cool a 2.5, at least in my experience it has been. I don't have AC but I do have a built 2.5 making around 170 hp and the stock cooling system keeps the temp right around 195 no matter what the air temp is.

CherokeeBen said:

Why do you need a different setup than stock? A fully functioning stock cooling system should be more than adequate to cool a 2.5, at least in my experience it has been. I don't have AC but I do have a built 2.5 making around 170 hp and the stock cooling system keeps the temp right around 195 no matter what the air temp is.

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wow, that's cool, what mods do you have done to your 2.5

It's a high performance crate motor from 505 Performance. I don't have a complete list of all the modifications from stock but they do include a hotter cam, higher compression (have to run premium now), some head work, and roller rockers. If you want more info just give them a call.

Overland said:

So replace the fan studs with short bolts, and run one or two electric fans from whatever looks close enough in the salvage yard? I've been through many a fan in the four door, busted one pulling out of an alley once, so "period correct" xj fans are out. It's a wonder the last one is still in there.

This truck does have AC, but the little radiator lacks the space for an auxiliary. Should I find electric fan circuits in the harness, or at the fuse block? Something I'll need to add myself? Where would I get the signal for the relay, in that case?

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Not totally sure, but I believe that both the 4.0L and the 2.5L share the same t-stat housing? If so, then pick up a 97-up t stat housing run either a 97-up factory sensor, or other sensor that fit to a thermo switch that will turn the fan/s on/off when necessary. Definitely need to use relays. I would also install a master/aux switch so you can override the fans if you feel they should be on longer or whenever you want.

Otherwise, I believe that most off the shelf, parts store stock replacement rad's (and some other aftermarket as well) have a threaded place to use a older stock sensor with a 2-wire gm weatherpack connector.

There seems to be quite a bit in common between them, as I'm finding out. If I were to replace the radiator with the wider one for a 4.0, I would also install the wider condenser, and eliminate the fan. Fan circuit is simple, the only things I wouldn't have on hand are the sensor and later thermostat housing.

I believe I would do the swap because the other is more common, easier to find in stock, may perhaps perform better in extra hot weather with A/C under conditions of extended idle, and because CherokeeBen doesn't have one.