I have owned this truck for 4 years now and in that time I have had to replace the thermostat housing o-rings at least twice a year and I am really getting sick of it. is this a common problem? I am using cummins parts and I don't know why it keeps on leaking every 4 to 6 months. It drips on the belt and it starts squeeling, that is the most annoying sound and I have to install a new belt for it to stop, it is kinda expensive to buy a belt at least twice a year. Any thoughts on a more permanent cure for this stupid leak.

 

First of all make sure there aren't two o-rings against the head instead of one.
Sometimes the old ring will be so smashed and old it looks just like the metal.
Could also be over pressure from a bad radiator cap.

 

Or a warped housing. Remove the housing and clean it up. Then place it up against something flat like window glass. If it's warped you will see some gaps. The housing could also be cracked. So look it over real good. JMHO

 

thanks I will check for an old o ring but I would think that would leak almost immedatly. Mabey I will get a junkyard thermostat housing and see if that will take care of it