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View Full Version : YJ over heating

Bert338
10-02-2005, 12:36 AM
Ok guys I need some help on this one, its driving me crazy trying to figure it out.

I have a 90 YJ, I 6, EFI, auto tranny.

If I drive at highway speeds my heep starts heating up (230 +). I've replaced the radiator, the cap, put in a two speed electric fan. It also seems I'm getting a lot of heat coming from the tranny.

Anyone have this problem and if so how was it corrected?
dozer209
10-02-2005, 01:58 AM
u might want to try putting in a trans cooler i know when i did that on my jeep it cooled the temp down. that might help your problem
Knuckelhead
10-02-2005, 09:00 AM
Do a search in here, lot's of information to be found...
DUSTYCEDAR
10-02-2005, 01:08 PM
do u have anything blocking the radiator? lights and such?
when u put in the new rad did it get craped up with dirt from the block?
Gary Soupy
10-02-2005, 07:30 PM
Have you changed the Thermostat?
Bert338
10-03-2005, 03:16 PM
I'll check the thermostat and I'll put in a transmission cooler.
Knuckelhead
10-03-2005, 03:22 PM
Where are you going to put it?
imported_Smitty
10-03-2005, 04:56 PM
I also have an 90 and I know that there are two different water pumps for it. One is a reverse rotation pump for use with the serpentine belt. If the pump was changed and someone had to switch out the pully the wrong pump could have been used.
Gary Soupy
10-03-2005, 06:01 PM
My thermostat had a chunk of gasket lodged in it. It could only open a little.
edudley
10-03-2005, 08:08 PM
Bert

Did you remove the original fan when you added the electric units. If you have a new radiator and a good thermostat then be sure you have a good fan shroud and a properly working fan clutch. it should be stiff to turn when it is cold. If it spins freely replace it wih a good one. The $50.00 ones just don't cut it. Also be sure the timming is correct and not too far advanced. This will casue some heat. The most comon thing I see is a worn out fan clutch. Good Luck
Bert338
10-03-2005, 09:42 PM
I'm going to go pick one up this weekend and then I'll see where it will fit. Any recommendations? I do have A/C.
Bert338
10-03-2005, 09:46 PM
edudley
New electric fan with shroud. Old fan removed.
Bert338
10-09-2005, 12:27 PM
UPDATE
Ok, replaced the thermostat and that made a diff right off. Tested the removed thermostat and it would open, but only partly. So at higher RPM (highway speeds) I'm thinking that it wasn't pushing the water out of the block fast enough. I've also went ahead and put a transmission cooler in. Located it on the drivers side of the radiator in the engine compartment.
Knuckelhead
10-10-2005, 06:53 PM
On the back side of the radiator? Remember, if both the auxiliary cooler ports are on the bottom of the cooler your cooler will be full of air and be of little use....
Bert338
10-10-2005, 08:37 PM
I'm not an expert here but, if the transmission pump is pushing fluid how would having the ports on the bottom make a difference? I've seen off road racers with oil and trans coolers on top of rigs.
Knuckelhead
10-11-2005, 08:27 AM
Fluid is heavier than air, if the fluid enters the cooler from the bottom and leaves through the bottom, any air that is being purged from the system when you hook it back together will be trapped in the upper part of the cooler with no way out, unless you turn your jeep over? :D