i have a cooling problems and i need to know what degreen thermostat to run ion my cj7 4.2 in line 6. it is over heating and i dont know why, i have a new radiator, fan clutch, fan, hoses, thermostat, and coolant flush. what else could it be?

water pump...everything else has been eliminated.

Or you have the wrong fan. Someone else on here had that problem a couple weeks ago. The serpentine and v-belt fans spin opposite directions. Put your hand over the grill and see if air is being pulled or pushed through.

Sometimes it is hard to tell exactly what direction air is moving with your hand. A coupld sheets of TP would let you know exactly what direction the air is moving...

195 degree. If the engine is overheating, a cooler thermostat won't help it unless it's overheating because the thermostat is bad.

Few more things to check:

You NEED a shroud. Without it, too much air loss.

Check you timing, too far advanced or too retarted, and you could run hot.

If you are running too lean, it could also cause excessive heat.

Make sure your thermostat is actually operating properly (I've had a few failed new ones). I run a 180 degree T stat. 195 would be ok too. Don't go less than 180, it could cause problems running too cool.

On the thermostat, drill a 1/8" hole at the top side of the large flat area. This is to help prevent air traps in the head (especially on the 4.2).

Do a search for cooling problems or overheating and you'll find some good info, especially from LEVE.

Man I must be lucky
I don't run a shroud, just the OEM 4 bladed fan and I'm running 180 dergees when it 90* outsde in slow traffic. The PO put the 180* thermostat in there and I've been to lazy to change it.

Maybe it the 4 core radiator I put in htere a couple of years ago.

OK, maybe a 4 core is overkill on a 4.2 but it helps keep the engine cool when the plow is blocking all the air flow. [img]/ubbthreads/images/graemlins/smile.gif[/img]

I would check waterpump also. They do wear out sometimes.

How did you check the temp of the engine to determine it's over heating or is the water gushing out the radiator cap. Also a leaky head gasket can cause overheating also. Check your compression.

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Check you timing, too far advanced or too retarted, and you could run hot.

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Does anybody know how to manually adjust the timing on a 4.0 FI engine? Ever since I swapped in a 4.0 head and the MPI on my 258 I've run hot. Even a three core radiator, new water pump, shroud, hood louvers, don't work. I can control it with an auxillary pusher fan, but that's a lot of work! I know the MPI is supposed to control the timing, but I've thought about grinding off the ear on the distributor and using the old hold down. Any thoughts?

I too have cooling and pinging problems with my MPI, there is a Hesco forum I just found Here