Giberish33
Veteran Member
I don't know if this is the correct place for this kind of post but I just got done doing a thermostat replacement on my 1997 Jetta and it took me several hours. I learned a trick at the end that I feel other people should know.
So it should be a fairly straight forward job, but in the various video I watched / write ups I didn't find a clear step that explained where the oring was supposed to go. When I pulled the flange off the thermostat was still in there with the oring attached. I assembled everything with the oring behind the thermostat and it was leaking when I poured coolant back in.
The oring needs to go in front of the thermostat between it and the flange. That was the next issue. I couldn't get the oring to stay in place when reassembling and it would always slide off to one side and get pinched between the flange and the block. I tried grease to hold it but that didn't work any better. Crazy glue on the oring and then on the thermostat to the block was the answer.
TL;DR use crazy glue on the oring to thermostat contact and then clean up the mating surface for the thermostat in the block and put some crazy glue on that surface then hold the thermostat in place while it dries. Once dry the thermostat will hold itself in the block and you can put the flange back on without shifting the oring around or pinching it as you tighten everything back down.
I specified the body in the title but I'd wager this tip is applicable to essentially any other thermostat replacement.
So it should be a fairly straight forward job, but in the various video I watched / write ups I didn't find a clear step that explained where the oring was supposed to go. When I pulled the flange off the thermostat was still in there with the oring attached. I assembled everything with the oring behind the thermostat and it was leaking when I poured coolant back in.
The oring needs to go in front of the thermostat between it and the flange. That was the next issue. I couldn't get the oring to stay in place when reassembling and it would always slide off to one side and get pinched between the flange and the block. I tried grease to hold it but that didn't work any better. Crazy glue on the oring and then on the thermostat to the block was the answer.
TL;DR use crazy glue on the oring to thermostat contact and then clean up the mating surface for the thermostat in the block and put some crazy glue on that surface then hold the thermostat in place while it dries. Once dry the thermostat will hold itself in the block and you can put the flange back on without shifting the oring around or pinching it as you tighten everything back down.
I specified the body in the title but I'd wager this tip is applicable to essentially any other thermostat replacement.