10 replies to this topic

[MiniLuke]

Hi, Quick question (probably quite a stupid one, sorry!). When reassembling an engine should the gaskets be used dry or should a sealant be used as well? "The Book" does not suggest using a sealant, so I am guessing dry? (Oh and I have tried using the search without success, which probably confirms how daft the question is!

[wile e coyote]

Varied opinions to follow here no doubt so here's my take... - head gasket, water pump, gearbox etc dry is fine (I always use some non hardening gasket goo on the thermostat housing) but diff gaskets need some sealant....

[mini93]

id also use some between the bearbox just incase, and trasfer case and timing plate n case end

[Southy]

For the Diff Housing I would use some sealant on. I would also use some sealant on the Half moon gearbox seal and also the timing case cover. For the rest I just use a smear of grease to hold them in place, this is more than enough.

Edited by Southy, 14 March 2009 - 10:26 AM.

[Dan]

A thin smear of RTV is ideal on gaskets that need to contain a volume of oil rather than just a spray of oil mist. That means the front plate gasket and timing chest (cover only the lower half of these, both sides with just a smear) and the transfer gear case, gearbox gaskets and diff side cover gaskets (cover all of these, both sides but keep the coating thin). The diff casing itself has no gasket (unless it's an auto) but needs a smear of RTV. The rocker gasket does well with a coat of something non setting like Hylomar blue, mainly to keep it aligned while you tighten it down. The thermostat gasket and any sandwich plate gaskets should also use Hylomar. Never coat a head gasket (it is coated already with exactly what it needs). Nothing else really needs it and it will only make dismantling things later much harder, although you can use some RTV if you want. Wherever you use RTV the important thing is to keep it thin, it doesn't take much to seal anything and if you use too much it always finds its way into the engine and gobs things up with big lumps. Keep it out of threads and holes and keep it thin and keep it even. When you can just see a hint of the colour of the sealant on the gasket you have used enough but if you don't make the coating even it will affect the way parts fit together.

[mk1leg]

I always use Hylomar blue as this never hardnes but sticks like s**t...............

[mike.]

I may aswel add onto this question while i'm here as my engine will be being rebuilt not far from now. Which bolts (if any) require or benifit from the use of copper grease/grease or locktight?

[Pauly]

Genuine rule for myself is, to use hylomar on paper and sometimes cork gaskets (if they are prone to leaking) and on head gaskets nothing.

Paul.

[mike.]

Any opinions on the question i added?

Thanks

[Dan]

Copper slip anything that is used to hold something to the outside of the engine where it is exposed to the elements but not anything that holds main castings together. Don't copper slip anything that has a critical torque figure or anything internal. These parts are mostly constantly bathed in oil anyway.

[Pooky]

Copper slip anything that is used to hold something to the outside of the engine where it is exposed to the elements but not anything that holds main castings together. Don't copper slip anything that has a critical torque figure or anything internal. These parts are mostly constantly bathed in oil anyway.

So use copper on the clutch slave bracket but not on the flywheel cover?

Should the main castings fixings by loctite'd?

Thanks