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[vauxox]

hi just about to do my oil cooler can anyone tell me if there is a sealant that i can use apart from vauxhall grey i read somewhere that you have to use this and leave for 24hrs is this true i would be gratefull if anyone can give some advice

[Marks DTM Calib]

There is a loctite alternative (cant remember what it is though), hermatite (none of the varients) is good enough in my opinion.

Vx is the best place though....

As for 24 hours, yes it is prefered but, can be used after 1 or 2 in reality

[vauxox]

thanks just thought id save myself a trip to the dealers but maybe false economy thanks for letting me know

[Cliffo B]

Dont use any thing else but the GM product. Make sure the mateing flanges are super clean. I used a combination of 360 grade wet or dry and finished with medium Scotchbrite. Try and avoid deep scratches. Then finish off with a good clean, useing celly thinners or a similar degreasant, to give virgin grease free flanges ready to accept this special sealant. Leave to set as long as possible. I would  consider at least overnight for a reasonable cure.Hope you do Ok.

[vauxox]

thank you

[vauxox]

i will let you know the outcome

[biggriffin]

i use good ol silicone from b+q use it every were exuast gaskets,rocker covers, and oil cooler half the price twice as good. if its a quality silicone sealer its better, its stable up to about 900.c  never had a problem with it yet. go on try it. o and by the way its not genuine vx

[ScottieMV6]

Correct me if I am wrong but the proper stuff from Vauxhall is £8 a tube (just checked my invoice). Good quality sealant in B&Q is about £8 a tube (not sure how that is half the price). I fail to see how anything is better than the stuff the manufacturer uses without any problems

[Kevin Wood]

Good quality sealant in B&Q is designed for putting round your bath not for sealing coolant under pressure in an engine!

It will also give off fumes which can kill a Lambda sensor when used on cam covers, etc. It will break down on contact with hot oil over prolonged periods and can end up blocking the oil pickup, perhaps lunching the engine.

At least use a sensor safe RTV sealant designed for automotive applications, although this won't be any good for the oil cooler cover IMHO.

As said, oil cooler change is a significant amount of work, makes sense to do the job once and use the right sealant.

Kevin

[JamesV6CDX]

When I bought my MV6, and took it apart, this is what I found:



Not sure how co-incidental it was, but shortly after doing the top end job, the engine seized and went BANG big style.

Despite checking the sump before starting etc - I reckon it's this kinda treatment that ultimately killed her 

[biggriffin]

 r.t.v.  stands for "room tempreture vulcanastion" meaning it goes off "hardens" hence after a while it starts to leak. silicone sealer stays plyable. yes there are various types of sealents, looking at that photo that looks like a sealent not silicone. ive used silicone for quite a few years and had no problems whilst using it.

[Kevin Wood]

Vulcanisation means to form a durable rubber-like substance, not to harden. RTV sets just as flexibly as bathroom sealant but it is properly designed for the environment. It is oil resistant and does not kill lambda sensors like a silicone sealant would.

Look at James' cam  covers. Notice how there is loads of excess sealant around the plug wells but none in the camshaft areas? That's because it has broken down on exposure to oil and is probably what clogged the oil system and caused the engine to throw a rod through the block. So much for saving £5 on a tube of the correct sealant!

RTV is not suitable for the oil cooler cover plate anyway, because we are talking about a metal to metal flange joint with no need for that level of flexibility.

Kevin

[vauxox]

iv never liked the idea of lumps of silicone or any other sealant floating around inside an engine and can imagine how easy it is to block an oilway or water way it makes you wonder how many engines have been wrecked over wrong full use of silicone i have lost count of engines i have stripped to find this floating around inside

[dbug]

As Kevin says silicone sealant is for baths and gutters not for car engines!!  Use the correct sealant that has been formulated by the manufacturer for that particular application (sealing metal oil cooler plate to metal block).

Kevin is also correct in that vulcanisation does not mean the product hardens - vulcanisation is a chemical process for converting rubber or related polymers  into more durable materials via the addition of sulfur or other equivalent "curatives". These additives modify the polymer by forming crosslinks (bridges) between individual polymer chains.  The vulcanized material is less sticky and has superior mechanical properties.