I just changed the thermostat & gasket on my 67 Parisienne and it leaks from the thermostat housing when engine runs. I just tightened it to what I think is the safest I should.
I would take the housing and sand it on a flat surface to see if it is warped.
If not take a file (sometimg straight) and wrap sand paper around and sand intake to see if it is warped.
I had that issue as well. I draw filed the housing and it would seal great cold but warp and leak warned up. Then rechecked it and seamed straight but cold again. Tried using silicone but the warp broke the silicone seal. I finally bought a new cast iron one and period correct. I think Dorman makes it. It was cheap. Under $20.
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'68 Parisienne 2+2 Convertible Matador Red (Resale Red but not for sale).
That blue or red gasket compound fixed me up. I had a leak at my housing soon after the engine ran a little on the warm side. New gasket wouldnt do it. Cleaned it up, applied a bead of the gasket compound, no more leak!
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72 Nova SS, 66 Beaumont Sport Deluxe, 09 Pontiac Solstice GXP Coupe
I doubt its the issue, but one thing people forget is that RTV has a shelf life. The V, for vulanizing, goes away with time and the stuff doesn't cure or set properly anymore. I was just taking apart an old Lincoln that was probably rebuilt 5+ years ago and some of the RTV was still sticky, clearly too old.
Also make sure that the recess that the thermostat sits in is really clean. If not the thermostat will not let the housing seat properly on the intake manifold.
I took it all apart, cleaned and sanded on the manifold and hose side, cleaned it all again, used some blue gasket compound and put it back together. I borrowed a torque wrench from a friend and followed the shoppers manual instructions to tighten to 28 lbs and no more leaks. Drove the car this afternoon before the rains came, heating inside is perfect too.
A torque wrench is one of the "must have tool". I know they can be pricey but you can't go wrong when you follow the factory specs on anything from wheel nuts to thermostat housings. A neighbour has one of the new snap on digital tools, I think he paid $700 or so but boy was a nice wrench
$700, Yikes! I bought a 3/8 torque wrench from Princess Auto for $20. I have a better quality 1/2 inch drive from Cdn Tire that was on sale for about $70. They seem to do the job. Yes, tools can be expensive for the "quality" ones but having the proper torque is a must.
I understand the importance of the right tool but $700.00 on a torque wrench is too much for me. We can really go overboard ... then would have to explain stuff to the wife :(
went away from lotions and potions, im now running a silicon gasket in ali frame I think mr gasket makes it, I have used sheet silicon before to seal bad leakers.
