To use gasket sealant or not

[COMMERCIALMAN]

Hi All, What are your thoughts on using gasket sealant and what parts should i definately use it and what parts i should not.? Im refitting my virtually bare engine so your thoughts are appreciated. Also one other thing i am replacing the engine steady bar and as the bracket is connected to the head i am a bit concerned when i undo the head nut it will disturb the head gasket. I suspect it will not as the other nuts will be tight. Should i take caution?
Thanks
Jason

[bmcecosse]

NO gasket seal! New engines didn't have it - so why put it on later ?
The bracket should be on top of the head nut - with another nut on top of the bracket. Longer stud should be fitted there for that purpose. But you say 'bare engine' - so what's the problem ? You don't have much option but to loosen the nut if you have to move the bracket - but do try to connect it as is first.

[PAULJ]

Undoing the nut will be fine, I usea sealant for everything excep head and manifold. the trick is not to use too much. You should also not use it where end float is required and acheved with a gasket and not around oil seals

[PAULJ]

[quote="bmcecosse"]NO gasket seal! New engines didn't have it - so why put it on later ?

They probably didn't have it in the olden days Rolls Royce use Hylomar, it says so on the tube.

[mike.perry]

I use Hylomar if I need to hold a gasket in place whilst it is bolted down, the classic example is the rocker box gasket which needs to be attached to the rocker box, which is then located in position and bolted down, hopefully without the gasket moving out of place.
If the two surfaces of the components are smooth and have a gasket between them then they should not need sealant.

[alanworland]

I obtained a manifold/exhaust gasket from our local depot and they said that they use a silicone sealant in place of the usual copper/asbesto and aluminium/asbestos type gasket!
I know silicone sealant is good for high temperatures but that joint could quite easily get to 400/500 deg centigrade, must be better stuff than I thought!

[COMMERCIALMAN]

Thanks for the input all. I have used Hylomar in the past but have questioned if it was needed. I will try to use without. I have cleaned all the metal surfaces so there should be no problem there. All the components going back are NOS or the original so everything should fit properly.
Best Wishes
Jason

[downsey]

i always use a little bit of gasket sealant for insurance. Nothing sucks more than putting something together only to find out it leaks.

[les]

It's a case of theory and practice, flat joint faces should be oil tight, but are not always, why chance doing the job twice, a fine film of sealant can't do harm and increases the chance of an oiltight engine.
As previously mentioned not on head or exhaust though. These are my thoughts on the subject.

[PAULJ]

The stuff i use is Silcoset 152, remains flexable from -60 to 300c its fantastic stuff.

[dfyates]

No sealant on head gaskets, just a film of oil. However, if the face of the head or the block is marked or scratched, you will be better off using hylomar. Don't use anything on manifold joint, it's a [Don't swear or you will be banned - Admin] to get off!

[dfyates]

oops sorry didnt know you couldn't use b u z z a r d in here!

[IslipMinor]

Assuming that both surfaces have been cleaned thoroughly, on gaskets between two machined surfaces I use a good smear of grease on both sides (makes it much easier to dismantle, if required). For gaskets next to an unmachined face side of the gasket, e.g rocker cover, sump, I use a thin film of sealant on the unmachined face and grease on the other. On head gaskets it depends on the gasket material, for copper a smear of grease on both sides, again to aid removal, but for composite materials, including exhaust manifold, nothing at all.

I also grease any studs, e.g. thermostat housing, liberally to make sure they will come off at some point in the future!