Leaking Woes

[BlueCobra]

Help!!

I have a Superformance with a 351 Ford Racing crate engine that has developed a leak in the thermostat housing gasket that connects to the manifold. It has the reservoir tank on top of the elbow connector and I have replaced the gaskets with Felpro gaskets that were recommended, but that soaked up the coolant and began to drip again. I then pulled that back off and used a silicone gasket seal from a tube and that didn't work.

Anyone out there got any suggestions .

This should be a simple fix, but has turned into a nightmare.

Any help would be appreciated.

Dan

[scootter]

Does it have an O ring grove or just a gasket? I used the gray RTV sealer on everything, and it worked good.
Scott

[SSSammy]

Dan, assuming there is not a hairline crack somewhere, try one more time with a new FelPro gasket. Clean the gasket surfaces on both the water neck and the manifold with a razor blade. Wipe down with lacquer thinner. Use a waterpump and thermostat specific silicone gasket sealer.



Smear it uniformly all over both sides of the FelPro, just thick enough to cover. Give it 10 min to get a little tacky before you bolt the water neck back on the manifold. Just snug the bolts up overnight, then the next day run them up to around 25 ft-lb, so you don't squeeze the sealant out while it is wet. Good luck!

Sam

[Bob Taulbee]

Dan,

A common thing wiht those T-stat housings are, they tend to bend if they are over tightened. When you remove it, use a straight edge to see if it has a bow in it. If so, you can use a block and some sandpaper to work it out.

[BlueCobra]

Thanks for the help.

It does not have an O ring; It actually takes the the gaskets from a 302 1968 mustang (and other models).

I will try to use the gaskets again with the silicone sealer and see if that work.

Dan

[MacGyver]

If sealer was not applied to the the bolt threads it could be leaking from there giving the appearance the housing is leaking...

[BlueCobra]

Thanks Macgyver

I did not try that; maybe that is why it keeps leaking. I'll try that when I put it back together.

[MacGyver]

I have fought that battle before only to discover the leak was around the bolt threads. This can happen on t-stat housings as well as front cover and water pump bolts. Be very carefull and check front cover and water pump bolt threads as they can be a bottom casting for the bolt hole causing a hydrolock of sorts breaking the casting when bolts are coated in areas when the hole bottoms out instead of penetrating a hollow. A friend of mine recently broke a chunk of his block off using too much sealer in an area where it wasn't needed. i recommend probing the casting with a pick first. If the hole bottoms out you shouldn't need sealer. If it penetrates into into a water jacket you should definatily seal the threads. A thin coat on all bolts should ensure a good seal regardless.

[STL Mark]

I may have your best answer. I had this same problem this week. I called two different auto parts stores - they had the same question for me, and the same answer for the solution - which has worked. Check this out -

They asked - is you water outlet chrome? I said - why yes it is.
They said it's warped.

I said - it has only 4000 miles on the new engine.
They said - no mater - it's warped.

In disbelief, I removed it and put it on the counter - yep warped.
I installed a plain old cast iron water outlet - and all is fine.

Don't bother with fancy gaskets, or messy glue/sealer - just get a plain cast iron water outlet (paint it if you want) and problem solved - forever.

[Rick Parker]

Just a thought, be sure that either the manifold or the thermostat housing has a machined recess for the thermostat to register into, one of them must have this. Put a light coat of gasket sealer on the suface of the part that has the recess, install the themostat, the gasket and let it set up for a few minutes, THEN install the neck & tank assembly onto the engine. Be careful that the thermostat does not become disloged and fall down while attaching the neck. This assumes the surfaces are flat as mentioned previously. 12-15 lb torque is plenty. All the Windsor manifolds I have seen have blind holes for attaching the neck and do not require sealant on the threads.

[xlr8or]

The chrome housings can be used but you need to sand off the chrome on the sealing surface first. I've done that a couple of times with no leaks.

[BlueCobra]

Well thanks for all of the tips.

It is a chrome housing, but evidentally it is not warped enough, because I put a fair amount of blue sealer on it and let it set for 15 minutes and cranked it down pretty tight; let that cure overnight and it seems to be working.

Time will tell.

[scootter]

Make sure to recheck the bolt a few times. Mine seemed to loosen for some reason.
Scott

[BlueCobra]

Thanks Scott, I'll be sure and check. I am still a little bit leary.

[bigstew]

I had the same problem with a Ford Racing water inlet housing. The leak was at the bypass hose connection. Ford did not machine the threads so they seal when tightened. It appears the leak is at the gasket, but it you have a heater hose it may be coming from the screwed in bypass hose fitting.

[madmaxx]

I vote for the warped housing. Next time it leaks put it on a flat surface and you will be amazed. Buy a new one use the gasket sealer and just snug up.

[tomh440]

If it does leak in the future.

Run a flat file over the housing AND manifold area. Sometimes there is a 'raised' area around the bolt holes.
I agree with the chrome housings too, use a cast iron or steel if possible.

Tom