Which fluids to cool?

So story goes I am swapping my aw4 for an ax15 in my 92 I6 cherokee in the future. A few years back I installed a nice stacked plate fluid cooler for my aw4. Since it won't have any fluid running through it after the swap should I bother leaving it installed to cool any other fluids? Keep in mind I live in north carolina so there is no real extreme heat I deal with except for like three months.

Oil?
Steering Fluid?

My cherokee has always ran fine while wheeling and I am pretty hard on the suspension and body of the jeep while the 4.0 never sees very much wild action as I rock crawl with a light foot. Should I just remove it and stash it in the garage until it has another calling in life?


TIA

Oil might be nice if you can figure out how to do it safely and economically, but I'd be more inclined to change engine oil regularly and run the power steering return line through the cooler. Power steering pumps do wear out more often than whole engines, it seems. My old GM truck had a steering cooler not unlike a small tranny cooler. It would also increase the total volume of fluid in the system, which might not be a bad idea. I don't think you'd need anything more than a couple of lengths of hose and a couple of clamps, since the return line is not under high pressure.

I ran a B&M stacked plate cooler on my power steering pump on my 94. I never killed a pump, but I was only on 31's... if it's in there, you might as well.

Be careful when pulling the existing line off your fluid reservoir, as I snapped the nipple off when I went to do mine. Old plastic gets brittle.

themauler said:

... the 4.0 never sees very much wild action as I rock crawl with a light foot.

Click to expand...

Normally I would say cool the power steering fluid, but it primarily heats up when the engine is at high RPMs for extended periods. You aren't doing that, so I don't think the power steering fluid temperature is an issue for you.

HappyDog said:

Normally I would say cool the power steering fluid, but it primarily heats up when the engine is at high RPMs for extended periods. You aren't doing that, so I don't think the power steering fluid temperature is an issue for you.

Click to expand...

I disagree.

Big rocks+Lots of steering effort= Hot power steering fluid.

I've heated mine up slow crawling to the point where it bubbled the paint on the hood above the pump.

run the power steering fluid through it.

87manche said:

I've heated mine up slow crawling to the point where it bubbled the paint on the hood above the pump...

Click to expand...

That's one HOT pump

I have a mini P/S pump, tube & fin, about 7" long and 3" wide. Seems to do the trick quite nicely. The 10"x8" stacked plate cooler might be a bit of overkill for the P/S pump. IMHO.

ParadiseXJ said:

That's one HOT pump

Click to expand...

it's still in the jeep.

I never replaced the pump, just the fluid. I beat on my junk mercilessly. Sadly the hood is starting to rust through where I bubbled the paint.... Meh, it's not like I cared about the sheetmetal anyway.

87manche said:

I disagree.

Big rocks+Lots of steering effort= Hot power steering fluid.

I've heated mine up slow crawling to the point where it bubbled the paint on the hood above the pump.

run the power steering fluid through it.

Click to expand...

Thank you for the correction! I don't do big rock-crawling -- what little experience I have is in small rocks, like the Granite Staircase in Anza-Borrego, where I slow-crawl in 4-LO at low engine RPMs (under 2200), slow-crawling to allow myself time to avoid the worst holes and rocks.

What kind of engine RPMs are typical when you do the big rocks?

HappyDog said:

Thank you for the correction! I don't do big rock-crawling -- what little experience I have is in small rocks, like the Granite Staircase in Anza-Borrego, where I slow-crawl in 4-LO at low engine RPMs (under 2200), slow-crawling to allow myself time to avoid the worst holes and rocks.

What kind of engine RPMs are typical when you do the big rocks?

Click to expand...

whatever it takes. With a 5 speed it's a bit different than you auto guys. usually below 2K RPMs, but I have been known to go way past the redline. 4 liters love 6 thousand RPMs.

87manche said:

whatever it takes. With a 5 speed it's a bit different than you auto guys. usually below 2K RPMs, but I have been known to go way past the redline. 4 liters love 6 thousand RPMs.

Click to expand...

I always found that the 5 speed liked low range better off road.

As for heat versus steering use, I had always assumed it was steering use, otherwise GM would not have put a cooler on the pump of my old K2500 pickup, whose 350 v8 seemed to do most of its work at a fast idle.

Matthew Currie said:

I always found that the 5 speed liked low range better off road.

Click to expand...

that IS low range.
I wheeled 35's and 3.73's for a while.

It's way better on my clutch with 4.56's now, but I still tend to keep it slow and low in the RPM range.

unless the situation dictates that I beat on it, then I'm all in on screaming 4.0