Thermostat

Someone help me out here. It sounds very basic but I'm not having any luck. I can't keep the thermostat neck from leaking on my 351 Windsor. It's brand new but is one of those after market chrome deals. I've put gasket sealer around the neck and bolted it down to specs but still can't keep it from leaking. Who's got a sure way on how to install the neck and thermostat.

Check the intake manifold with a flat edge and make sure it's square where the water neck bolts on. Also try getting a new water neck that has the O-ring type seal instead of a gasket. They tend to seal a lot better.

Seriously, get a good one from FMS. Take a look at this thread...

http://www.fordmuscle.com/forums/all...t-housing.html

Robert

Take the neck back off and clean up the gasket surface real well. When you've got it spotless, lay a sheet of 120-ish grit wet/dry sandpaper on a nice flat surface and run the gasket surface over the paper. Any high/low spots should be readily apparent. Keep sanding on the neck until you have a consistent uniform pattern over the entire gasket surface. Clean it again and you should be able to install it dry, with no sealer at all. also, make sure your t-stat is sitting properly in the machined recess of the intake.

When sanding the gasket surface you should use a figure "8" stroke to keep the surface square. I always use Loctite "Gasket Maker on both sides of the gasket or on the O-ring seal for thermostats. Only a very thin film (.010") is necessary. With a flat surface and sealer it will never leak (it can accomodate up to .010" of warpage). Clean up is easy too because when it comes time to replace the thermostat the sealer will peel away with the gasket. No scraping or sanding needed.

Should I also use a regular type gasket along with the rubber o-ring seal? With a film of sealer as well?

All you gotta do is lay that chrome POS on a piece of 80 GRIT sand paper on a flat smooth surface, and slowly flatten it. Slide it back and forth until all the surface scratches are the same depth and go in the same direction then swirl it in a circle and check for any spot the cirrcular marks might have missed , if there are none then you are done.

Don't over tighten.

Don't waste time with smaller grit than 80G, it's just time consuming, the 80G marks will never cause a leak.

If you want to use a rubber O Ring, then you will NOT need a gasket, and the housing you bought will need to be machined for an O ring. Also, try to stay away from using more than the thinnest film of sillicone that you can make. Any thicker and you are only wsting it.

Hope that helps.


FE

NO!
Never use a gasket when the O-ring is used. You will cause more problems than you have now.
A note about O-ring seals:
the groove has to be smooth and the bottom surface it mates with has to be smooth. Using the sealer will help hold the pressure but if the groove has pockets or flashing in it the O-ring will not seal effectively.

Ok, looks good. Hasn't dripped a drop in twenty four hours. I'll keep an eye on it. By the way, the flange on the old inlet seemed warped just a little.

Thanks so much to all!

120 grit, 80 grit???? I use the side of a 14" chopsaw blade as it is spinning!!!!!!!!!