U302 Overheating

[Joe Reusch]

My dad has a U302 and it dosent run very long without overheating. He went through everyting in the cooling sytem and he took the thermostat out to make sure it wasnt sticking. It does get plenty of circulation and it is really moving through fast. So my question is, is it the head gasket or the head. Any help will be apperciated.

Thanks, Joe Reusch

 

[bog]

I had this problem on my 445. An old timer told me I had to drill an 1/8" hole in the thermostat. It worked very well, problem went right away.

 

[KJS]

A Jetstar 3 in school had an overheat problem also. It was not overheating before the overhaul but after it was overhauled the temp gage said it was overheating. The problem was that the student had an airlock in the back head so the temp gage was reading steam and not coolent. Another case I have seen is that a freind purchased a JS3 super and also had an over heat problem. The problem with that one was who owned it before was too lazy to put the pipe back in between the two heads and just put frostplugs there so the rear head never got cooled. (I don't think this is the case in yours).

One other thing I would check is do you have the right radiator pressure cap? The more the pressure rating the higher the temperature.

 

[klw445]

I agree with "Bog". I also had the same problem. Since the thermostat is so far from the source of heat (the head), the thermostat doesn"t think the water is hot. The 1/8" hole allows enough flow for the thermostat to sense heat and therefore open. Hope this helps.

 

[Anonymous-0]

Did he actually get the radiator cleaned or did he just run water through it?

There was a guy with a zAs over on the MM website just a few weeks ago who was having that problem. He said he had good flow through his radiator too. Finally took the top tank off the radiator and about half the cores were plugged.