Intake manifold gasket/sealant

[drewrgs]

Hi all,

Looking for some advice/tips on refitting the intake manifold on a 1974 GTV.
My first attempt ended in a coolant leak between the head and intake manifold. (Thought I had the mating surfaces clean enough, but could do a little more around one of the water inlets in hindsight.)

Can anybody recommend a decent gasket adhesive/sealant?
Don't think my first choice was up to the job.

There's a fair spread between the manifold mounting studs and I think a little insurance around the water inlets could be useful.

Drew




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[Colin Byrne]

Hi Drew
Yea as you say there is not really that much clamping force with those studs given the wide area, and there is often corrosion of the Ali in the critical areas.  We run a smallish ring or red rtv silicon around the water pathway holes on both sides of a new standard manifold gasket.  It's thick enough to fill any corrosion voids and seems to get good adhesion to both the gasket and the ali surface.  It's also very flexible so no issue with thermal expansion ect.  We've never had any leaks from the gasket using this method

hope that helps

[drewrgs]

Thanks Colin,

I'll clean things up and give the RTV a try.

Cheers

Drew


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[Paul Byrne]

Drew, just generalising a little what Colin says:

We try to limit RTV as much as possible due to its bad habits. The inlet manifold coolant holes really need it (I had the same issue as you), and there is no need to put any type of sealant anywhere else on this jointing face. The other places where we find it may be needed are the thermostat housing top, the front of the crankshaft pulley where oil can leak out through the keyway (especially with aftermarket Aluminium pulleys), and maybe on the diff pinion flange around the nut--if oil is making its way down the splines. These last two a probably pretty rare with standard OEM parts. RTV Red does also seem to work very well on the extractors to head face when applied to the copper gaskets.

Would like to mention that for all rigid joint faces except the head gasket we have found that loctite 518 applied as a thin bead to one face seals completely and is easy to remove later. No gaskets are required on any rigid engine/diff/ gearbox joints, with the possible exception of the water pump, diff sump pan and the engine sump lower pan--here just smear the 518 on both sides of the gaskets.
The 518 is now available in syringes and you can easily make consistent perfect beads---almost seems a pity to bolt the halves together sometimes as it looks so good!
Cheers,
Paul

[Colin Edwards]

+1 for Permatex Red RTV and Loctite 518!

[drewrgs]

And thanks to Paul as well.
Let's see if I can keep the garage floor dry this time!

Drew


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[xitsurf]

sorry to bring up old thread, 
  Understand seal around coolant holes.  So no sealant around intake holes .  gasket still stays flat with sealant on top and not on bottom? (ie fully sealed around intake).  Maybe a stupid question but replacing manifold this weekend.
Thanks

[Colin Byrne]

As long as you use the RTV sparingly around the coolant holes, as mentioned it's really there just to fill any voids created by corrosion, then you shouldn't have any issue with the intake sealing on the gasket with no sealant

[GTV-074]

About to refit inlet manifold, water pump, front pulley after doing the usual replacement of 50+ year old
Bits of Alfa's finest....

So just want to confirm, is it ok to run a small bead of sealant,

.around coolant holes on the inlet manifold?

.thermostat housing?

.water pump?

And a follow up question for Colin, does a standard front pulley (replacing front main seal) need any
Sealant on the keyway as mentioned above or is that for after market stuff?

Thanks,

Paul.

[xitsurf]

I went through this a few months ago,  had coolant leaking into inlet .. blowing lots of smoke on start up. 
    new gasket and rtv around coolant holes (only)   and a smear of grease on paper Carb gaskets just to give a good seal.
      This fixed the problem.

[GTV-074]

Thanks for the reply...

I think I'll just use it sparingly, just to be safe.

Cheers.

[Colin Byrne]

In the past I've put a tiny amount of sealant at the end of the keyway before the washer and the nut, also made sure the faces of the washer and nut are in good condition, and a small amount of thread lock on the nut, never had any oil leaks out of the front pulley on standard or the aftermarket ones

[GTV-074]

Thanks Colin ....

Last time i did one was in the 80's!

I can't remember what i did back then, altho i did find a small bottle of permatex at Mum's (looks like the brown one, who knows where i put it!).

I have some new stuff so as mentioned i'll use it sparingly and dab a bit on the keyway as suggested.

Cheers,

Paul.