bad_idea

I have a 90 Comanche I just picked up with the 2.5L and a manual. The radiator is shot. I plan to swap in a 4.0L and AW4 OR SBC w/ TH350 down the road. Still waffling on the swap. I have the SBC w/ TH350 and the 4.0L sitting around and the skill, shop, and time to swap. I say all that to say this, can I swap in a 4.0L radiator with the 2.5L? Figure the 4.0L radiator should cool a SBC and will definitely cool the 4.0L. I don't want to do the swap right away, so need to put a radiator in it.

I know there is a separate MJ forum. I posted this same question there, but that forum seems to get minimal traffic. I assume the Cherokee and Comanche are the same in the radiator area, so the question should fit in this forum too.

Turbo X_J

Is this just for fun or do you have the math to back it up? Plenty of literature out there on engine cooling system design.

bad_idea

Zero math. If it isn't enough radiator for the SBC, then I can pull it and set it in the rafters as a spare for my Cherokee. I will have ZERO use for a 2.5L radiator once I yank this one out.

Cummins93

Yes

bad_idea

Cummins93, do you have experience with putting a 4.0l radiator on a 2.5l? What hoses did you use? Thanks for the help.

bad_idea

I fitted the 4.0L radiator to the MJ today. Fairly simple. Remove the 2.5L radiator, condenser, and all associated 2.5L radiator specific brackets. The 4.0L radiator bolts right in, no mods needed. I used the 4.0L hoses and just had to extend them. I cut the top hose right beside the a/c compressor and added in a 9" long section of pipe. Cut the bottom hose beside the air box and add in a 6" long section of pipe. The MJ already had the stock mechanical fan removed and a large electric fan in it's place. I will mount that fan to the 4.0L mechanical fan shroud. The remote power steering reservoir was mounted to the side of the 2.5L radiator mounting brackets, will have to mount that with some redneck engineering. Last issue is the condenser, the 2.5L setup had it mounted aft of the core support. To retain the a/c I will have to get a condenser for a 4.0L.

All in all, not a mod worth doing if you are retaining the 2.5L. Considering my plans to swap out the 2.5L, it is worth the effort for me. I don't plan on swapping out the 2.5L for a while, I have a couple other projects ahead of this one. I would like to have the truck functional if the 2.5L will run.