Hey, I have a 67 Mustang with a 1983 5.0 HO engine in it. I keep blowing thermostat gaskets, and I dont know what the problem is. I had the O-ring style housing and that was very leaky, so I put an actual gasket on it and after a few weeks it blew and coolant went everywhere. I decided to replace it with a new gasket, and put on form-a-gasket to get it to seal, and it worked! for about 2 days and it blew again. What is my problem? It usually happens when I am getting on it. (high RPM) I replaced the thermostat thinking that is what it was, and I got one with a pressure release valve to no avail. If someone could help me out I would appreciate it.

 

maybe the housing is warped?

 

Maybe, that is what I was thinking, any other suggestions?

 

check the intake mounting surface for flatness and also the housing piece too. don't overtighten the bolts as this will warp the housing and tend to make it leak too. you could always install some underdrive pulleys and slow down the water pump also to lower the pressure it makes pushing the coolant around in the system. also make sure the water pump bypass passageway if not plugged up too as this take some pressure off the thermostat too.

 

I'm not sure but my thermostat has a bleeder valve on it you have to be sure it is point up when installing the therm, and i know it might sound stupid but make sure the therm is installed in the proper direction. i would get a new housing just to be safe while your at it.