Gaskets And Sealant

[Grim.Badger 15]

I'm hopefully going to be replacing my exhaust manifold and gaskets, dipstick sheath and sump gasket this weekend. These will be the first gaskets I've ever done so I'm not sure if I know everything. Do you have to use any sealant compound or alike when you're putting new gaskets on

 

Cheers

[dd_156ar 0]

I replaced my cracked exhaust manifold yesterday with a new one and didn't use any kind of sealant... guess what, I don't have an air-tight join, so I'm going to have to take it back off and do it again... Still, you live and learn i guess!

[hengti 2]

can't use sealant on the exhaust manifold gaskets (due to the heat involved)

might be able to use sealant on the sump gasket, although i'd have thought it best just to clean up the mating surfaces, ensure they're true and rely on the gasket in its own

 

what sealant are you proposing using? there are different types - some are more like adhesives (eg. blue hylomar) that are used together with gaskets (a bugger to clean off if you need to take it apart again) and others are more like 'instant gasket' that are used in place of paper/cork gaskets

[dd_156ar 0]

can't use sealant on the exhaust manifold gaskets (due to the heat involved)

might be able to use sealant on the sump gasket, although i'd have thought it best just to clean up the mating surfaces, ensure they're true and rely on the gasket in its own

 

what sealant are you proposing using? there are different types - some are more like adhesives (eg. blue hylomar) that are used together with gaskets (a bugger to clean off if you need to take it apart again) and others are more like 'instant gasket' that are used in place of paper/cork gaskets

 

I got something called 'exhaust assembly paste' for high temperature joints... Will this be OK to use?

[hengti 2]

I got something called 'exhaust assembly paste' for high temperature joints... Will this be OK to use?

 

can be used on pipe joints - but I wouldn't use it on manifold gaskets (most expand and harden with heat and eventually crack and break up, which'll leave you with a lose manifold and blowing)

 

it should be possible to get a good seal at the head by following some of this:

1. genuine gaskets are apparently the best (never had problems with pattern ones myself though)

2. make sure that the studs are in good condition and are screwed into the head tightly

3. make sure that both the manifold mating face and the head mating face are very clean

4. put the gaskets on the right way round

5. after fitting it, run it for a few days and then nip up all the bolts again

Edited May 23, 2006 by hengti

[dd_156ar 0]

can be used on pipe joints - but I wouldn't use it on manifold gaskets

 

it should be possible to get a good seal at the head by following some of this:

1. genuine gaskets are apparently the best (never had problems with pattern ones myself though)

2. make sure that the studs are in good condition and are screwed into the head tightly

3. make sure that both the manifold mating face and the head mating face are very clean

4. put the gaskets on the right way round

5. after fitting it, run it for a few days and then nip up all the bolts again

 

Great, thanks for the advice. To be honest it's a real mismatch of studs, bolts etc. So I think I will try and start from scratch so to speak.

 

Oh and sorry for the thread hi-jack Grim.Badger!

[Grim.Badger 15]

Great, thanks for the advice. To be honest it's a real mismatch of studs, bolts etc. So I think I will try and start from scratch so to speak.

 

Oh and sorry for the thread hi-jack Grim.Badger!

 

That's okay, you got some more of my questions answered for me

I'll try without any sealant as all the nuts, studs, gaskets and manifold are genuine Peugeot parts. Just hope I can get all the studs out, especially as there are only 7 in at the moment and I'm dreading finding out the eigth is snapped off in the head Damn previous owner!

 

How do I know which way around the gaskets go? Can I just check against the old ones?

[Beastie 1]

Just to add to the good advice already given about manifold gaskets: It's always wise to tighten the manifold only with the engine completely cold. Sometimes it's possible to cure a blowing manifold gasket by tightening with the engine warm... but .... the differring expansion rates of the cast iron manifold and the aluminium head means that tightening the manifold when hot produces as very significant risk of cracking the manifold as it cools down!

[huxley309 0]

Tighten the manifold bolts starting from the centre as it allows the gasket to move outwards while tightening making for a better seal

 

On the sump most seem to use rvt sealant,works well as my engine build used this on the sump

 

Cost me about £18 from a cit dealer mind...it is howver meant for the job in mind

[DaveK 0]

is there anywhere to buy exhaust gaskets apart from the pug dealers? been doing some searches and it seems (from the few i found) that the dealers are pretty much the only place to buy em?

[hengti 2]

Dave K - is this for your 8v or 16v? i've only experience of the 8v gaskets, which are individual (4 req'd) - is the 16v gasket 1 piece?

anyways - some High St places keep pattern gaskets, but the 8v ones are stupidly expensive (about £5 each!!)

 

definately pays to get the job right first time!

 

Grim Badger - it's difficult to see because of the space/angle problem - but, if you use a little mirror, you'll be able to see which way round the gaskets go over the ports (plus - the mirror's handy for checking how good your wet&dry job on the head is). it is possible to put them on the wrong way round so that the ring in the gasket overlaps the ports - it'll be obvious once you've had a look

Edited May 23, 2006 by hengti

[Wurzel 16]

Just to say a word about sealant on the sump gasket. In an ideal situation, you shouldn't need any sealant other than the gasket provided.

 

You need to ensure that the mating surfaces are scrupiously clean though without using anything too abrasive to distort the surfaces. That horrible silcoset type sealant that is often used can be deadly for your engine if used in too great a quantity. I've take a few engine apart where the sealant has spread into the sump, broken off and started to block the pump gauze. The last engine I stripped had spun two big end bearings and the pump/sump was full of sealant beads (and bearing)

 

I prefer to use no sealant on the mating surfaces, just the gasket but then put a bead of sealant around the outside when the sump has been refitted (torquing the bolts in the correct sequence and definately NOT overtightened - tighter is not always better).

 

The sealant I use is an aviation fuel tank sealer which is perhaps a little ott but is meant as a once only fit. The sump is not meant to, and will not, come back off in a hurry. The seal however is first class.

 

There was a discussion on sealants some time ago, and a few good suggestions for the type of stuff to use (off the shelf). Have a quick search and see what comes up

[dd_156ar 0]

Well, I've just installed my new exhaust manifold for the second time. Got the proper gaskets from local Peugeot dealer for £8 and after taking advice from here I didn't use any sealant and tightened the bolts in the centre first. Great news - no leaks.

 

Cheers for all the advice!

Edited May 24, 2006 by dd_156ar