How much is too much for cooling? (5.9L ZJ)

[Mitch502]

My question is about my 98 5.9L ZJ. I'm currently collecting parts that I needed, and as I recently ran into some info (on here!) that satisfied me, going to be purchasing a lift soon. Anyway, here is my question...


the 5.9L already is known for being a furnace, so creating any type of blockage in front of the radiator is troublesome for my mind to comprehend. I want to put a trans cooler on it, but also would like to put a power steering cooler on it. My worry is that by adding those, the air coming in will be warmer, and block more air from the radiator, resulting in cooling issues.

Is this a legitimate concern, or am I being a worry wart? Plans will consist of ~5" lift and 32"-33" tires. No other mods to speak other than planning on being weighted down with gear, and rarely tow anything.

Thanks,
Mitch

 

[Mitch502]

Also, this is the radiator I am purchasing, pending googling reviews of it...

https://www.radiatorexpress.com/pro...NUM,+2-ROW+HD+&part_id=218169&aaia_id=1315953

 

[mtbxj87]

What about mounting the trans and p/s cooler somewhere else their own fan? Better fan clutch and/or better electric fans, I'm not sure what's on ZJs stock. Hood vents have helped on my xj, also I take the rubber gasket between the rear of the hood and cowl in summer. Regear accordingly to tire size? Just some ideas

 

[K2ZJ]

What about mounting the trans and p/s cooler somewhere else their own fan? Better fan clutch and/or better electric fans, I'm not sure what's on ZJs stock. Hood vents have helped on my xj, also I take the rubber gasket between the rear of the hood and cowl in summer. Regear accordingly to tire size? Just some ideas

The 5.9 comes stock with hood vents and dual electric fans. I know the guys I wheel with in Moab in June have pusher fans as well. I would do my best to not put anything in front, but a trans cooler is a great idea. I am considering pulling my trans cooler from the front (4.7 stroker) and mounting it with its own fan.

 

[mtbxj87]

Aux trans coolers are a must.

 

[1stDeuce]

I don't think I'd worry too much about either of those coolers "pushing you over the edge"... You won't be working it that hard out on the trail anyway, mostly just bumping along at low throttle. If you're dragging trailers up grades, and it's overheating already, then you can worry, but you probably have other parts that need repacing. If it still has the original radiator, or a cheap aftermarket one with poor heat rejection, that also might cause issues, but a quality radiator and two fans should be fine, even with a small trans cooler and ps cooler plumbed in. Worst case, turn off the A/C and roll down the windows. Running the A/C (or defroster) puts WAY more heat into the system than either of the little coolers you're contemplating.
My $.02.
C

 

[SoCal Tom]

I've spent a lot of time with Early Broncos, which are pretty much the standard for undersized radiators and overheating. Putting the trans and PS coolers in front of the radiator shouldn't be a problem if the problem is overheating at low speed. If you are worried about overheating at highway speeds, then you have a problem to fix.

What I see is that most of the time people that overheat at low speeds are driving automatic equipped trucks, and they are driving too slow in high range.
Here is what happens:
First you have to understand the way a torque convertor (TC) works, at low speeds ( below 1500RPM) the TC will create extra torque, doing this generates heat. Under normal circumstances, like the Mcdonalds drive through, the extra heat is absorbed by the trans cooler in the radiator. The transmission fluid will heat up, but most of the heat is moved to the radiator. You may not see this on your temp guage, because your temp guage measures the temp of the water in the engine not the radiator temperature.

When you drive on the trail, you may drive for several miles or even hours in high range like this, and the thermostat will open up and so the temp still stays normal on the temp guage, however the water in the radiator is now much warmer than it normally would be.
Then, you come to an obstacle, that requires a bit more throttle, and probably needs even more heat out of the transmission. Suddenly, the engine starts to over heat, because there is no extra capacity in the radiator.
To correct this, if you are on a long slow trail (running at under 1500 rpm or so), then either down shift, or put the Transfer case in low range. Now the RPM stays higher, the transmission doesn't create the extra heat, and when you get to the obstacle, there is cool water in the radiator to absorb the extra heat.

The trans cooler will help, since it can cool the trans cooler than without a trans cooler, but ultimately, if you have an automatic, keep the RPMs up.
Tom
PS it also doesn't hurt that this runs mechanical fans faster if that is what you have

 

[Mitch502]

What about mounting the trans and p/s cooler somewhere else their own fan? Better fan clutch and/or better electric fans, I'm not sure what's on ZJs stock. Hood vents have helped on my xj, also I take the rubber gasket between the rear of the hood and cowl in summer. Regear accordingly to tire size? Just some ideas

Where are some more common places to mount a cooler? I can't think of anywhere to mount it under the hood that would be beneficial...

 

[Mitch502]

The 5.9 comes stock with hood vents and dual electric fans. I know the guys I wheel with in Moab in June have pusher fans as well. I would do my best to not put anything in front, but a trans cooler is a great idea. I am considering pulling my trans cooler from the front (4.7 stroker) and mounting it with its own fan.

My 5.9L has a single electric fan, converted to a Taurus motor...I'm assuming pusher fans go in front of the radiator? I'm googling it now...

 

[K2ZJ]

Brain fart sorry, one fan and pusher fans go in front.

 

[mtbxj87]

Derale makes a remote stacked plate cooler with fan you could put under the jeep