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Discussion Starter · #1 ·
Hi all
I'm hoping to get round to re torquing my head bolts this weekend and was looking at the Haynes manual this morning. It says in there that on re attaching the cam cover a silcone sealant should be applied at areas which, according to the drawing, appear to be at each corner of the cam cover. Is there a specific grade/make of silicone sealant that should be used? Is this similar to the vinigar-smelling bathroom sealant type stuff (not that I'd use bathroom sealant...I was just wondering is all)?
Thanks
Kev
 

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Yes, it's bascially the same, but possibly higher temp rated and more oil resistant. You can buy it at any decent motor factors, and it fits in the same "guns" used for bathroom sealant etc.

As for just at the corners- forget it. Use a good coating all the way round on both the inboard and ouitbaord seals, especially in the old dizzy blanking plug area.
 

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Discussion Starter · #3 ·
Originally posted by Bubbles:
[qb]As for just at the corners- forget it. Use a good coating all the way round on both the inboard and ouitbaord seals, especially in the old dizzy blanking plug area. [/qb][/b]
I thought all 9000's had to leak at this point...sort of part of the character

Cheers for the advice. I'll pop out and see what the local shop has.
Kev
 

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IIRC, the diagram in the Haynes refers to the older design of cam cover gasket where there were separate rubber blanking plugs for the cam end cutouts. On the later design, these are part of the gasket. Nonetheless use of a sealant can help hold the gasket in place while you fit it and so is probably a good idea.

I *think* you may need to check that whatever you use is safe for lambda sensors, but I am not certain about this.
 

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Originally posted by Mr. Person:
[qb]They should sell stuff called "Valve Cover Gasket Silicon". I just bought some recently so that I can replace my valve cover gasket. I think its a blue tube, but I'm not too sure. [/qb][/b]
True, it's in a blue tube, but it's about 8 times the price of regular automotive silicon.

I've not heard of any requirement to be "cat safe".
 

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As usual, I'm only parroting what I've heard elsewhere

From this page:

The O2 sensors (also called Lambda sensor) suffer contamination from silicone sealant and some other engine additives. You can get silicone safe sealant its usually a thicker non transparent and feels like a paste compared to normal tacky silicone. It should be used on all surfaces that silicone is used on in the engine.

Harmful content to the sensor in Non sensor safe silicone is actually the silicone solvent and it is excreted as it dries.This is absorbed into the intake via PCV from gaskets in the engine it is used on and burnt as combustion, this results in it ending up at the O2 sensor. It's a real worry when used on the exhaust manifold.  [/b]
See also for example this page and see how it's described as "sensor safe".

See also this page and look at item D.

All this worries me, because I used ordinary blue gasket sealant on my cam cover, and replaced the O2 sensor, and now the car runs rich
 

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Interesting, John.

A bit of further browsing throws up lots of info on sensor safe sealant.

I can see that silicon itself might cause a problem for the sensor, as suggested by the lambda info page, but I'm not so sure about the curing gasses. Mosts MSDS list acetic acid as the gas released on curing, which is simply a hyrdocarbon and will be broken down in the combustion process. There must be something else as well that is not listed...
 

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It would be wise to heed the warnings and use the correct sealant if available.
I bought a car years ago with a blown engine,(very cheap )and on pulling the engine down, I found the oil pump intake clogged with silicone sealer. It appeared to have expaneed like foam on contact with the oil, and consequently blocked off most of the oil intake. Further to using the correct sort of silicone , I'd be very careful to use it sparingly so as to prevent any excess breaking off in time and lodging somewhere dangerous. Just my 2 bobs worth though.
Can you buy a ready made gasket for the valve cover? I've always gone for this option with what is known as aircraft sealant out here in Oz. (it is a contact cement type product, rather syruppy and very thick consistency, which yo paint on to the surfaces before positioning the gasket)
 

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Please be aware that any surplus sealant that gets squashed out from under the cam cover internally, may potentially block an oil port anywhere it should happen to lodge (assuming it doesn't slip through to the oil filter).


My recommendation is a very thin layer and generally sparse application. More is definatly not better in this case!
 

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Hi Aus9000T,
Your previous entry wasn't visible when I wrote mine, for some reason - so didn't mean to replicate your wise comments. (Only 40 mins between posting's so maybe I needed to do a screen refresh).
B-regards,
Paul
 
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