Recommended inlet manifold sealant ?

[Mandrake]

Hmm, just found this:

http://docs-asia.electrocomponents.com/ ... 01eb70.pdf" onclick="window.open(this.href);return false;

Contains 2.5 - 10% Silicone Dioxide.

[Mandrake]

And this page and a number of others list it as "oxygen sensor safe":

http://www.valco-cp.com/hylomar.htm" onclick="window.open(this.href);return false;

I suppose it should be ok then, especially in the small amount I would be wiping on the gasket face.

That page makes reference to a second solvent free version of it as well ?

Hylomar is impervious to oil, gasoline, glycol and other engine fluids. Hylomar is oxygen-sensor safe, seals gaps .01" or less, and performs at constant temperatures up to 600°F. With Hylomar, components are assembled, reused and reassembled with ease. Use Hylomar for thin gaps without a gasket or as a gasket dressing. It holds the gasket in place during assembly as well as giving a great seal. Use Valco’s All-In-One Silicone™ for wider gaps in place of a gasket. They are great companion products. Hylomar should be removed using Valco’s Solvent 184™.

Hylomar is also available in a solvent-free formulation that is also impervious to oil, gasoline, glycol, and other engine fluids. Solvent-free Hylomar is environmentally friendly and provides immediate assembly/pressure capabilities. Non-setting and non-hardening, even at high temperatures, solvent-free Hylomar withstands rapid variations in temperature and permits easy disassembly.

[myglaren]

Always got it at my local motorist shop. There are half a dozen near me and all stocked it.
Places like Halfords will have it if you can't find anywhere better.

[lexi]

Are you sure it is not the acetoxy acid in high modulous silicone that is the danger to your sensor?
Low mod silicone has a different BS number and is usually non toxic. Maybe check that out. Hylomar is fine......Maybe do both sides of gasket to take up discrepency.
I used to have rocker cover on and off Land Rover regularly. I glued the gasket to rocker cover face with Red Hermetite and put some grease on paper gasket. It went on and off regular.

Can you not work the manifold on a glass plate with sandpaper on it? True it out a bit. We did that with carb faces for airtight seal.
I nearly said carb faeces there. " I have sh**t in me carb"...........oh no! who would have done such a thing

[Mandrake]

Thanks everyone, I've ordered a 100g tube of Hylomar universal blue from amazon - should be here on Thursday (by the way it seems Halfords no longer stock it)

Are you sure it is not the acetoxy acid in high modulous silicone that is the danger to your sensor?
Low mod silicone has a different BS number and is usually non toxic. Maybe check that out. Hylomar is fine......

No its the silicon content that is harmful to the oxygen sensor (as well as lead, phosphorous, ethylene glycol to name a few others) but from my reading there are a few safe sealants that still contain silicon - it must have something to do with how that silicon is chemically bound to the rest of the mix as to whether it stays inert or whether it is harmful.

The Hylomar universal blue is specifically listed as oxygen sensor safe so that's good enough for me.

Maybe do both sides of gasket to take up discrepency.

Yep that's what I'm thinking - a thin smear on both sides of a new gasket. Should help hold the gasket in place on the bottom half while trying to manoeuvre the manifold into place too, as it has a tendency to get hooked and lift out of position.

[stevieb]

Simon has directed me to this thread, so I thought I'd chime in with my two pen'neth.

The gasket crushes when fitted, and therefore must be replaced each time. This is a pic of new versus old:



As you can see there's quite a difference in thickness.

As for sealants, Peugeot recommend Loctite 5980 for re-sealing the sump, and a lot of people have reported using it on rocker covers too. The Loctite website says it's silicone based, but I'm sure I remember reading (probably on one of the data sheets) that the formula is such that its resistance to heat and oil minimises the leaching of silicone. How true this is I don't know, but I've used it successfully on my sump.

Hope this helps somebody in the future

[xantia_v6]

I am currently in NZ, and the cart spares places here sell "CRC Grey self forming Hi Temp RTV Silicone Gasket" Which says on the packet that its uses include intake manifold gaskets and it is sensor safe.

I don't recall seeing CRC products in the UK, but there must be an equivalent.

To stop the sealant sticking to the manifold surface, smear some oil on the surface before applying the sealant.

Hylomar blue has a finite life when exposed to oil, or probably petrol, it seems to slowly dissolve, something seen many times on the Jaguar V12 cam blocks, which were sealed at the factory with Hylomar blue.

[edit] According to http://www.henkel.com.au/aue/content_da ... keting.pdf" onclick="window.open(this.href);return false; , just about all of the Loktite sealants are sensor safe.?

[Mandrake]

Thanks for that.

The reading I've done suggested I stay away from RTV type sealants for this - they are a self forming gasket intended to replace the gasket completely, and very hard to get off again, so not really designed for something that comes on and off a lot like the inlet manifold.

I want to use the correct gasket with a small amount of non-setting flexible sealant as a "gasket dressing" which seems to be what the hylomar blue is. The tube has arrived but I haven't opened it yet to see what the consistency is like.

Interesting about the Jaguar cam blocks - in that application was a bead of the sealant being used as the sole compression gasket, or was it being applied as a gasket dressing to an actual gasket ?

In the later case I think it would last much better. In my application as a thin smear of gasket dressing on the air intake I think it would last a lot better - no direct exposure to petrol and a tiny amount of oil fumes from the breather. Most of the sealing is still done by the gasket, and the cross section of sealant exposed to the air flow would be tiny.

We'll see how it goes anyway. I'll still have a couple of spare gaskets after fitting it if I change my mind and want to remove it later.

[isisalar]

A bit late in the day I know, but I was in BL auto's today having some work done and they swear by this stuff :- https://www.dropbox.com/s/gmwxso4cq402p ... .45.50.jpg" onclick="window.open(this.href);return false;
Says it's sensor safe and has a very good gas assisted trigger system for application.
Cheers
Paul

[Northern_Mike]

Thanks for that.

The reading I've done suggested I stay away from RTV type sealants for this - they are a self forming gasket intended to replace the gasket completely, and very hard to get off again, so not really designed for something that comes on and off a lot like the inlet manifold.

With respect for your issues, I'd hesitate to say that an inlet manifold is designed to be put on and off a lot

I used Hylomar blue on the last inlet gaskets I fitted, but it was a while ago. 1993 cat-equipped Saab 900 Turbo, a 2001 Saxo 1.1 and a 1.2 Punto. Never had sensor problems I did the Saxo back in 2006 and it's still running to this day, and still belongs to my friend who had it back then. Even though his main car is now a Pious.

[Mandrake]

With respect for your issues, I'd hesitate to say that an inlet manifold is designed to be put on and off a lot

Normally I would agree with you Mike, apart from my GS I've not had the inlet manifold off any of the 4 cylinder cars I've owned even once...

The V6 is a different story though as many basic maintenance and troubleshooting tasks that are unrelated to the inlet system are an inlet off job due to the layout.

Check or replace the rear spark plugs or the spark plug leads ? Manifold off.

Check or remove injectors, fuel rail, fuel pressure regulator ? Manifold off.

Change the knock sensor ? Upper AND lower manifolds off.

Change either of the two rear (brown and blue) coolant temperature sensors ? Technically its possible with the manifold on I suppose if you have skinny dexterous fingers and a lot of patience, but realistically it's very difficult to work down in the plumbers nightmare area without removing the manifold.

Change the TPS ? Manifold off to access the bottom screw, especially if its seized solid as mine was. (Or remove the LHM tank instead - I prefer not to disturb the LHM return octopus least it break)

Remove and clean the ICV ? Manifold off. (Unless you've previously replaced the factory hose clamps with ideally positioned jubilee clips - then it is just possible without removing it)

Check for oil leaks on the rear camshaft boxes ? Manifold off.

You get the idea. All or nearly all of these tasks are possible on most 4 cylinder engines without removing the inlet manifold or anything else for that matter.

So yes the inlet manifold is going to come off a lot more often than a cam box cover or a sump.

I used Hylomar blue on the last inlet gaskets I fitted, but it was a while ago. 1993 cat-equipped Saab 900 Turbo, a 2001 Saxo 1.1 and a 1.2 Punto. Never had sensor problems I did the Saxo back in 2006 and it's still running to this day, and still belongs to my friend who had it back then. Even though his main car is now a Pious.

That's encouraging to hear. When you applied it did you apply a narrow bead and let it squeeze out when you assembled the joint, or did you smear on a thin layer across the entire gasket as if you were applying grease ? The latter is what I was planning to do as I don't want to use too much as a bead causing it to squeeze into the inlet ducting and upset the air flow by introducing a big lump.

[Northern_Mike]

I used a thin bead. I recall using a Stanley blade quite obsessively to make sure it was a narrow one,for no other reason than that was how I'd seen it done by the chap I used to help out at a back-street garage when I was a kid, and let it squeeze out when it was assembled. I can't imagine it makes a great deal of difference thinking about it, as a thin bead will likely just spread out to create a layer over the gasket as if one was applying grease.