As you can see, the little moon guy is shocked. 360's don't usually run hot for no reason, and 304's don't either. Check to see that the water pump actually has blades on it. I know that sounds wierd, but they DO break, corrode, or rust so bad that they can't push water. Check the radiator to confirm that the flow area is actually open and not all loaded full of crud. The WATER FLOW area and the AIR FLOW area. Make sure the fan clutch is working. Make sure that you have the correct fan SHROUD. Changing the thermostat won't help, and when you go back to the normal thermostat, drill a small hole in it to assure that the air can escape and the water actually reaches the heat sensor pellet. The hole can be less than 1/8"....no biggie, just DO IT!

CJDave

 

If the old thermostat was rusted, then all the other parts inside the engine are also most likely rusted, or at least corroded, as well. You might want to try to verify that it actually gets a decent amount of coolant thru the passages, but I'm not sure exactly sure how you'd go about doing that. Also, check the radiator for excessive corrosion or rust buildup. If it is, I'd recommend either taking it to a radiator shop and having them reverse flush the system, or get a new radiator. That should at least help the overheating problem. You might want to get an auxilary electric cooling fan, especially if it has an automatic transmission with a cooler. The cooler helps to restrict the flow of cool air that flows thru the radiator. I've heard that if you have an external tranny cooler that you can help keep the coolant cooler by putting the tranny cooler on the engine side of the radiator instead of in front of it. However, I haven't done this, and also have no idea what kind of adverse effects it'd have... But it's a Jeep we're talking about and I'd assume you have the manual tranny? Sorry about the rambling answer, but good luck with it!!! That waterwetter stuff helped my 454 out a bit, but unless it is running right near the correct temperature range anyway, it won't make a very big difference at all, as far as I have seen at least...

Tim
"The_Sandman_454"
/wwwthreads_images/icons/cool.gif '79 GMC Suburban 4x4 and '85 GMC S15 4x4

 

Check your timing, incorrectly set timing can cause a lean condition and a very hot burn.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Terry L. Howe http://www.off-road.com/~txh3202

 

might also want to check and/or adjust your fuel mixture on the carb. too lean would make it run too hot as well...

Tim
"The_Sandman_454"
/wwwthreads_images/icons/cool.gif '79 GMC Suburban 4x4 and '85 GMC S15 4x4

 

Okay, this is what I found out this afternoon. I completely drained the radiator. The draincock had this nasty rusty liquid goo on it when I pull it out, and the lower radiator hose spring was rather corroded, however, the water pump sparkled(which confused me too), so, tomorrow I'm gonna reverse flush the radiator and check the timing and see if those help. Also, Dave, why would I want to go back to the original thermostat? As in 190 degree, why is 165 deg bad?

Steve
/wwwthreads_images/icons/crazy.gifJust Empty Every Pocket/wwwthreads_images/icons/crazy.gif

 

There are two basic reasons I can think of. First, the radiator can transfer heat from the coolant to the air faster and more efficiently the greater the difference between them. If the temperature of the coolant going to the radiator is at least 190, the difference between the coolant and air temp would be greater as compared to the coolant temp at 160, regardless of the ambient air temperature.

Second, during cold weather start ups, condensation can form in the crankcase. A 160 degree thermostat would not allow the engine to warm enough to evaporate this condensation thereby allowing the liquid water to mix with the engine oil. You can see this effect when the oil appears milky. This, obviously, can cause internal engine damage.

 

I don't have much experience with AMC V-8's but other engines i've had overheating problems i generally troubleshoot in this order, i flush system (with radiator cap off, checking to see water is actually being moved by the pump in the radiator once the engine is hot, then check belt tension) i change the thermostat also (sometimes i just check old one one in boiling water on my stove) then have a shop clean your radiator, installing new cap, (system needs to have @12 to 20 PSI i think) and change any hoses that need to be. if i believe it's a cooling system problem still, i change the pump, then fanclutch, (i don't like flex fans) then radiator (adding another core if possible). this all assumes you have factory engine, radiator, shroud, and no big engine performance mods,

3/4tonYJ
/wwwthreads_images/icons/cool.gif'89YJ,4.3/th350/np231/Dana44/60

 

Yep, Them's two VERY good reasons....PLUS the emissions thing...they are less polluting when they are at the correct temp. NOT TO MENTION that you will freeze this coming winter with the already inneffective heater. /wwwthreads_images/icons/tongue.gif

CJDave