I'm replacing the water pump on my car.  I'm about to put the new pump in, and the manual says to coat the gasket with a 'suitable sealant'.  What might that be?  Some sort of silicone?  Is there a standard sealant used for a car's coolant system?  Or just a coat of grease or something like that, to make the gasket stick to the metal?

Many of the Permatex products are suitable.

[url]www.permatex.com/auto/autouh.asp?f_call=get_item&item_no=22071[/url]

muchas gracias

I havent found anything that beats old Brown, Stinky Permatex #2. Its been around for about 60 years so they must be doing something right!

i always just use a little wheel bearing grease.
it holds the gasket, and if for some reason
the pump has to come back off the gasket is still reusable.

I was sure I replied earlier but ??????


Permatex is classic, and smells great!  If I recall OK, it's a shellac, and you use alcohol for cleanup.

However, the old stuff has to be scraped off (another ritual of old), and you have to be very careful with all the aluminum parts.  I don't use it on them - too easy to gouge the metal.  

Nowadays, there's a lot of parts where they use RTV silicone instead of any gaskets at all, if you believe the manuals.

Some of you service techs tell us about this!

How can that soft rubbery stuff take the place of a sturdy gasket?

At any rate, assuming it works, with machined surfaces, if you go in there and use shellac & then scrape it later, I would assume the silicone will never again quite do the job anymore, because those close tolerances will be screwed up by the zealous scraping of the putty knife / gasket scraper.

I use RTV on things like this.

Should be just fine.

I've used Permatex Blue RTV for years.

#2 gasket sealer is supposed to come off easy but I don't like it anymore. And #1 hardened and you really have to scrape it hard to remove it.

With modern engines and modern machining practices along with good gaskets(not no-name aftermarket...just well known makers) no sealant should be needed. A very thin coating of grease( just enough to darken the surface) will let the gasket flow while you torque it down. An experienced tech. could do this without a tourque wrench but you should use one. Go in small steps and use a patern appropriate to the shape of the part or the man. specified. Absolutely DO NOT use to much torque!!! Water pump/coolant system gaskets many time have a bead of sealant already applied. In this case, use nothing but perfect cleaning of the surfaces.
BP