GM 350 thermostat housing gasket leaking

[The_Nuke]

Originally Posted by mk378
Multiple threads about the same problem is really bad ettiquitte. Find the old thread and post new information to it. That way the readers have the back-story of what was done so far.


And then prepare to get chastised for the resurrection of a long-dormant thread...

 

[cb_13]

Originally Posted by motor_oil_madman
If Teflon sealant compatible with antifreeze? I worry about that stuff getting in and clogging stuff up.

Yes, it was required on certain bolts on 3.0 Vulcan front cover jobs to keep coolant from leaking out.

 

[The motor guy]

Originally Posted by The_Nuke
Originally Posted by mk378
Multiple threads about the same problem is really bad ettiquitte. Find the old thread and post new information to it. That way the readers have the back-story of what was done so far.


And then prepare to get chastised for the resurrection of a long-dormant thread...



I forgot about that. You can't win either way other than to just hope they don't remember. lol

 

[The motor guy]

Is the black ultra permatex compatible with the paper gasket maker stuff? I cut my own gaskets

 

[The motor guy]

Any chance I can just keep using my $20 reusable gasket and then just put the Teflon sealant on the bolts? I think the bolts are where it's leaking from.

 

[michaelluscher]

I just did a stat and housing w/sensors on my SBC ('83 Grand Prix 305)

First meticulously clean the engine side of the equation

Second, buy a new ACDelco premium stat (do you want to open it up again?)

The Dorman housing is much thicker at the flange than the comparative ACDelco part, I bought one

I bought the $12 FelPro black w/orange o ring premium housing gasket, and ran some Thread sealer down both bolts, torqued to 20 ft lbs

I just did all the hoses and a cooling system flush on it today, for an original rad and heater core it hasn't leaked a drop anywhere I can see yet

Good luck.

 

[jhellwig]

Originally Posted by motor_oil_madman
Originally Posted by jhellwig
If it is the style of thermostat that is supposed to have the rubber gasket around the flange of the thermostat make sure that it is there. Some parts places will sell you a paper gasket that will leak instead of the right gasket.


How do you know if it needs a gasket around the outside of the thermostat?


The ring where the thermostat sits will not hold the thermostat snugly or flush with the machined surface.

 

[The motor guy]

Originally Posted by jhellwig
Originally Posted by motor_oil_madman
Originally Posted by jhellwig
If it is the style of thermostat that is supposed to have the rubber gasket around the flange of the thermostat make sure that it is there. Some parts places will sell you a paper gasket that will leak instead of the right gasket.


How do you know if it needs a gasket around the outside of the thermostat?


The ring where the thermostat sits will not hold the thermostat snugly or flush with the machined surface.



Oh okay. Well it sits in there just fine and doesn't move around.

 

[The motor guy]

I'll have to look and see if it's flush though, didn't notice.

 

[The motor guy]

Alright I got it all put back together. Instructions say to give it 24hrs to be fully cured. Gonna take the boat out on Tuesday and test her out. Upon closer inspection of the bolts it looks like they did use some Teflon paste thread sealant, although there wasn't much on them. Maybe it got filled with coolant too soon and started too soon initially. I'm not going to fill it up until Tuesday morning.

 

[The motor guy]

Thanks guys. Looks like it's fixed. She's dry as a bone now. I always thought Teflon based thread sealant or any sealant for that matter could only be used on tapered fittings like npt fittings. Guess not. Lol