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mounting my tranny cooler tomorrow?

W

white_elephant

NAXJA Forum User
Location
miami
so this is my question..


the top line is the hot oil that goes into the radiator....and the bottom one is the return....

so how do i run the setup...

some people tell me to connect the return to the top of the tranny cooler and then reconect to the tranny ...

somepeople tell me to connect the one that the oil enter by to the tranny cooler and then to the top of the radiator...

so which one is should i do?
 
i would disconect the entry to the radiator and conncet it to the cooler then cooler exit to radiator input that way your radiator takes less heat as the oil is cooled by the cooler first
 
lawnman said:
i would disconect the entry to the radiator and conncet it to the cooler then cooler exit to radiator input that way your radiator takes less heat as the oil is cooled by the cooler first
Click to expand...

That is the way my tranny guy told me to do it on my race car. Trans stays engine temp all the time unless under a load.
 
lawnman said:
i would disconect the entry to the radiator and conncet it to the cooler then cooler exit to radiator input that way your radiator takes less heat as the oil is cooled by the cooler first
Click to expand...

But if he does it that way the cooled fluid will be reheated by the hot coolant through the radiator so that doesnt seem ideal. Am i wrong?
 
Combatcm said:
I did cooler after radiator, it makes the most sense and I've seen more people do it that way.
Click to expand...



this makes more sense to me also..since the radiator is trying to cool it then the tranny cooler will help even more..
 
Part of an XJs problems have always been that they run kinda hot. The radiators are marginal at best so if you are at all concerned with engine temp then the trans cooler should get the hot fluid first to cool it before it makes the radiator even hotter. So to break it down it should be trans to trans cooler, trans cooler to radiator, then radiator back to transmission.
Thats the only way to keep both the transmission and the engine cooler, which is the whole concept of a transmission cooler in the first place.
 
I get what you’re saying but...

The trans fluid only runs through the bottom part of the radiator right? So I don’t see how it could substantially or noticeably affect the coolant/engine temp.
On the other hand since the radiator coolant occupies a much larger part of the radiator it can have a much greater effect on trans fluid temperature.

I could see how putting the cooler before the radiator as you suggested might also decrease the coolant/engine temp a few degrees at the expense of not being 100% efficient of cooling the trans fluid.
Doing it the other way, cooler after the radiator will keep the coolant/engine temperatures the same but greatly reduce the trans temperatures.

Does that make sense?

EDIT: I forgot if you’re worried about coolant/engine temperature why not bypass the radiator all together? That will decrease both the coolant and trans fluid as efficiently as possible right?
 
Last edited:
Just bypass the radiator all together. A cool trans. is a happy trans.

Don't worry about overcooling, your trans. will generate enough heat to keep itself happy.

If you're worried about startup in cold weather, put a thermostat in line.
 
I bought header wrap and wraped the exhoust pipe where it runs next to the tranny. Since it's all covered by skid plates I fiqured it may transfer a lot of heat to the transmission. I used the wide 6" stuff and it was nice to work with. My local speed shop sells it by the foot but buy a lot more than you think you will need. You can get small rolls but dam that stuff is pricy. I added a wrap around my home made air tube to slow the transfer of engine heat to the intake air.
 
white_elephant said:
ok..i will by pass the radiator..i just have a problem.....i dont know how to connect it since the hoses are presion hoses...
Click to expand...

Cut the lines off (try to get them square, but not necessary), deburr inside and out of the line, slide rubber transmission fluid or power steering hose over the end far enough to put two hose clamps on each end. Tighten them pretty snug and you're set.

It's low pressure so it's not critical to get a compression fitting or even a barb on there.

HTH
 
mount it on the driver's side in front of the radiator. Be sure to put the pads between the two finned surfaces or they will damage eventually. Mounting it here allows the electric fan to cycle on and off in traffic, which forces air through the cooler too (keeping the temps right where you want them). ;)
 
The radiator portion of the cooler doesn't do much, at least it didn't for me. When I bypassed it with a standard 10" Hayden cooler (aluminum), it dropped my temps 25-50 degrees lower than when the radiator cooler was plumbed and circulating to the Hayden.
 
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