I finally got to take the montero up north. We went to Christopher Creek. The Montero overheated, or at least increased in temp significantly, on the up and back. Each time on a long hill climb. By the way, it was a bit gutless up the hills as well. 55mph was a strain. Is my transmission overheating? This happened, even when I pulled off the thermostat.

Might have a head gasket leak? With the motor cool remove the radiator cap off and then start the motor does it bubble at all?

I replaced the thermostat and added some coolant. There was some bubbling about every 7 to 10 seconds. This was after I squeezed the radiator hoses to clear air.

Fill it right to the very top with the cap off and see if it keeps doing it. If it keeps having bubbles head gasket and or the head is not in good shape. Might have to start it a few times to get all the air that would be in there from doing the
thermostat. If that's all right might just be the rad. might need cleaning or replaced.

plugged radiator and a bad fan clutch

I was thinking of putting some steel seal in it for now. Has anyone ever used that stuff?

Sounds like you need to do A leakdown test and a compression test to see why it feels gutless. Did you just get it? What kind of condition are the internals in? Leakdown test is only way to know how valves are sealing, rings are sealing, etc. <img src="/forums/images/graemlins/confused.gif" alt="" />

What is that stuff? Is steel seal for the cooling system, or is it one of those snake oil treatments that claim to seal scored cylinders, and fix the compression on otherwise shot engines?

If it is for the cooiling system, like a leak fix, I strongly recommended against using that stuff. Even if it does temporarily fix a headgasket leak it will gunk up a bunch of other things in the cooling system, radiator, thermostat, heater core, all will be plugged up with that mess.

If it is snake oil, go ahead. I also have a bridge to sell you, and some beach front property in Iowa. <img src="/forums/images/graemlins/wink.gif" alt="" />

That isn't totally conclusive. If the cooling system was already low of coolant it may purge air for some time, those air bubbles may just be air. What would give you a better idea is one of those kits that test for exhaust gas in the radiator/cooling system.

For testing the fan clutch get an assistant. Get the truck up to operating temp. Then pop the hood and keep a look at the fan while your assistant shuts the engine off on que. It should stop very shortly after the engine is shut off. If it keeps spinning chances are that it is shot.

Beach front property in Iowa! Well hot dog! Ill get the Mrs. From cleaning the outhouse and start planning our future. Replacing the head gasket, it is. Thanks Doug. One last question. Could not properly bleeding the air out of the radiator have caused the problem. I may have been a little hasty last timed I worked on it.