I recently finished freshening up my 68 302. One of the things I changed was the old thermostat. I had ordered a new housing and gasket but was sent the wrong housing so just cleaned up my old one. I put the new thermostat in (the correct way), added a little bit of blue gasket sealer to hold it in place, put on the new deal and a small covering of gasket dealer and put in place. After I let it dry i reconnected my new hoses and added coolant to the radiator. I have it a once over look at all the hose connections for leaks and left it a few hours.
When I returned i saw dripping coolant. It was coming from the bottom of the housing connection.
I drained it back down low enough to take the hoses off and redo the gasket and sealant.
I know have a very small, slow slight drip when not running. I have not yet fired up the engine since redoing the fuel system etc.
My question may be stupid but I need to know if I should pull it off again and just replace the housing too this time to try to not have any drippage?
Is any amount bad? I am not how much pressure is in that system when running.
I’ve had the same issue with a new thermostat housing (intake is new too btw). Could not get the new one to seal at all, tried different gaskets, sealant etc…
I’ve heard the original (cast) piece is still the best, if it can be saved, mine could not.
Now to solve this I bought another housing which uses an O-ring seal instead of a gasket, so far after a few years 0 leaks, so that solved it for me
This is my experience with them btw
Fords are notorious for leaking there. Usually the cheap chrome aftermarket versions are the worst. But I’ve also had the O-Ring version leak as well. Best luck I’ve had is an original cast iron with a Fel-Pro gasket.
Personally, IMO, ANY leaking is bad because it’s not supposed to.
What I have seen more than once is , if you do not glue the T-stat into the housing it can slip out and get a piece of the edge between housing and manifold and cause a leak.
Czechmate68, if you go back in there and pull the t’stat housing check for cracks. Especially at the bottom. Many of us have cracked that housing when the t’stat slips down as described above. I could certainly buy a few beers with the money I’ve spent on those housings in the past.
I just replaced mine and have the exact same leak. Very frustrating. I’ve heard that the solution is to not use a gasket at all, just sealant. I might try that.
I tried numerous time to get the Permatex blue thermostat gaskets to seal on my 351C. They always seeped, I eventually concluded that the gasket themselves were porous. I used a self setting liquid and had no further problem
I replaced the entire cooling system this past Spring/Summer. I didn’t have any problems until I parked the car for the season. Now I noticed a slight leak at the housing. Gotta love it.
Wow, I just had a chance to check back on this and I must say I did not expect much but was pleasently suprised. Lots of great opinions and advice. So I plan to take it off again. It is the original housing so will check again for cracks. I did try to make sure the star was held in place to avoid slipping down.
I am getting a new cell to gasket and give that a shot before I go to replacing the housing with a new one which sounds like some have already tried that.
At least I feel better about not being the only one with this issue!
Much Thanks to all who took time to respond. I appreciate you all.
I agree any leak is too much and would drive me crazy anyways knowing it wasn’t perfect!
It’s just a pain in the as s to have to do something so simple multiple times.
Well, I pulled the old one off again. The t-stat was held in place well in the housing so know it wasn’t that. When I went to check for any cracks, I did find one on the right side of the main hose outlet, between that and the right lower bolt hole. I know that it was from me probably over tightening that bolt when I was originally noticing the leak. Funny thing is that it did not show on the face that joins the up with the manifold so not even sure if that was it either but glad to have caught that now before a major failure. So, cleaned up the surface real good and don’t have a choice now about changing the housing so just got my new aluminum repo from WCCC with a new Felpro gasket and going to get that put on tomorrow.
With a new felpro gasket, take rtv and coat one side with a thin, smooth layer. Lift it up and let that dry. Then do the same thing to the other side. Thin, smooth layer. Let it dry. Your basically making a “printo seal” gasket. Now you have silicone mating to both surfaces and forms a tight seal when bolted down. Never have a leak
Fel-Pro gasket and Gaasgacinch. Loop a rubber band through the basket handle on the thermostat and put a pencil through the ends to hold it in the housing until it is installed.
That is almost exactly what I did this time. Except I put a small amount in the onset them out the first in, made sure outside was still clean, let that dry them added a tho layer, gasket, another thin layer and mated it up. The great held in place great that way so no worries on it moving down between the main contact point. Letting her dry tonight and we’ll see tomorrow!
Quick update- after redoing my housing with a new Felpro blue gasket and Permatec blue gasket maker i refilled my radiator today and happy to say that so far no seepage. So that is progress. It is cold and not been tested while the engine is running or up o temperature yet. Hope to fire it up this weekend.
