rear mounted radiator

[possum]

Any pics or ideas. I found a couple write ups on the web but was wondering if anybody has done it to their MJ. i am looking for ways to make my V8 run a bit cooler.

[mvusse]

I'd think best airflow is where the radiator mounts in the stock location: the front. If your engine runs too hot, I would get a larger (thicker) radiator if that is an option, you could probably gain a bit by running transmission fluid through an external cooler and then the radiator in-tank cooler. Some electric fans on front to push the air through (in addition to the regular fan behind) might help.

 

Assuming this is in a Comanche, which never came with a V8, do you have a fan shroud? They make a HUGE difference. If there is none available for your setup, see if you can modify one that already fits the radiator to the fan, or one that fits the fan to match the radiator.

 

There are also products available that reduce the surface tension of the coolant for better heat transfer. Also running more water/less antifreeze will transfer heat better also.

 

And then the obvious ones: a cooler thermostat, or high flow thermostat, and a high volume water pump/smaller pulley on the pump.

 

Just about every one of those are simpler than a rear mounted radiator, and might work better.

 

An unusual way to do it that might work is to mount a second radiator in front of the current one. Run the coolant through the rearmost radiator first, then the front one. Should give you more efficient heat transfer from the coolant to the air.

 

Besides that, if you run uncoated headers, they release a lot of heat into the engine compartment. Enough so that it can cause an engine to overheat in city traffic. If so, you might want to replace them with stock manifolds or ceramic coated headers, or at least wrap them with exhaust wrap (high temp insulation), to keep the heat out of the engine compartment and blow it out the tailpipe, where it should go.

 

Good luck and have fun!

[pingpong]

I think DirtyComanche did that on his.

 

There are many advantages to moving your rad in the back.... mostly shortening the front/ moving the axle way forward.

 

I suggest you get two BIG Spal fans and that should cool it fine.

[brigarpeon]

Did this once on a 72 CJ because the fan would take out the rad when forging water. PITA to get filled and very hard for the stock water pump to keep the water moving enough to keep it cool. This thing would read OK by the gauge then all of a sudden overheat and squirt out all the water as steam.

Lesson learned: It did save the Radiator in forgings, it DID NOT keep the engine cool enough so it blew up the engine.

[possum]

Okay the I have seen a few other MJ's on here with V8s in them. So what do you guys do to keep your V8s cool in these little trucks. Mine was originally a 2.8. The stock 2.8 Rad works O.K. and I already have a seperate trans cooler and I am gonna install some LeBaron Vents. Ant other ideas? My trucks seems to like to run about 220.

[possum]

So here is my plan of action. I am going to disconnect the hoses going to my heater core and plug off the in and out on the heater core so no debris gets in. Buy a sizeable heater core and mount it as you would a tranny cooler and run my heater hoses to it. Much cheaper and more simple than a rear mounted radiator. BTW does anyone know what the little valve doohicky in the heater hose on the inlet is? Is it a check valve of some sort?

[camo89]

ok i know i new here but not to wheeling and rear mounted radiators

 

 

in my 1981 toyota with a 5.7 sbc

i used a 1974 chevy p/u radiator with the stock water pump and worked perfect

 

in my 1985 toyta 406 sbc

i used a high flow water pump and a griffen alumnium radiator

 

it got hot a lot

switched to stock water pump oh not hot aney more

 

1976 ford f250

460

just used the the stock 351 radiator

no problems even with 38s

355 gears and 3 ton of hay on the tralor

 

the key here is how you run the water and how the fans out back work

now for safty resons i have never done this with aney thing that dident have a cab (p/u)

 

i have always run water weter threw on the first fill up to help coal all the piping

 

i always use

1.75 exhaust tubing

a 50/50 mix of water and antifreez

and then 2 bottles of water weter

[mvusse]

So here is my plan of action. I am going to disconnect the hoses going to my heater core and plug off the in and out on the heater core so no debris gets in. Buy a sizeable heater core and mount it as you would a tranny cooler and run my heater hoses to it. Much cheaper and more simple than a rear mounted radiator. BTW does anyone know what the little valve doohicky in the heater hose on the inlet is? Is it a check valve of some sort?

 

Yes, it is a vacuum operated valve that controls how much coolant flows through the heater core (temperature control). Default with vacuum disconnected is wide open.

[JeepJukka]

I'm planning to move rad to bed, but plumbing it is big question. there isn´t enough room for pipes in under the cab and running them through cab......

there is hot already in summer.

 

ideas for plumbing?