Engine: Thermostat housing install - do the bolts get sealant? anti seize? (1950 2R5 pickup)

[rcke]

ok - got the thermostat housing going back on - the two bolts go into threaded holes that pass thru into the block (non-blind) - and of course I don't want those holes to leak....

Do I use anti seize only ? Anti seize plus sealant under the head of the bolt and in the housing hole?

[fiveftsix]

A little bit of thread sealant on the bolt threads won`t do any harm.
Geoff

[rockne10]

You need sealant on the gasket, not on the bolts. Anti-seize is never a bad idea unless it's use is specifically forbidden, as in tapered axles.

[rcke]

Yes i was all set on the gasket business - got my permatex sealant (80063 high tack).

It was the ends of the bolts passing into the water jacket that got me to thinking about anti-seize being enough (or not) to block water coming up through the threads and seeping out under the heads of those 2 bolts.

[fiveftsix]

You need sealant on the gasket, not on the bolts. Anti-seize is never a bad idea unless it's use is specifically forbidden, as in tapered axles.

I disagree with that statement, on old cars where the thread has over the years no doubt been stretched it does no harm to apply a small amount of thread sealant on the bolt threads.
Not only does it seal it also acts as an anti seizure too as most thread sealants have a silicon base.
and It goes without saying that something should be applied to the thermo housing gasket that`s common sense.
Geoff

[rockne10]

Out of curiosity, on which thermostat housings does the coolant have access to the bolt holes if the gasket is properly sealed?

[Bud]

I always use sealer on head bolts that go into the water jacket. Without it, coolant can wick up around the threads causing an external leak. Bud

[Bud]

As an added note, the thermostat housing bolts are head bolts and should be torqued accordingly. Bud

[fiveftsix]

On most flat heads Rockne,
The bolts go all the way through the Thermo housing as well as the head and into the block.
They do on my 170 Champion and also on all the head bolts as well on my L134 jeep engines.
Geoff

[rcke]

i figure i gotta go with EITHER anti seize or the thread sealant - so i'm going with some Loctite 577 or Permatex High Temp Thread Sealant # 59214

[fiveftsix]

I use Permatex #80632
Geoff