Paper Gaskets and "Lapping In"

[granit_silber]

During the saga that has become my replacing the thermostat and assiociated gaskets, I came across some info and need some clarification.

I read that one should expect some seepage until a paper gasket has "lapped in"? What is lapping in and how long does it normally take?

I ask because I scraped all the junk off the housing and corresponding space on the block, reassembled everything, and I still have a small leak from the housing.

It does seem to be diminishing, but just wondered if I get to do this again.
-ashley

[632 Regal]

I always use permatex spray tack gasket stuff ans never have any weeping.

never heard of gasket lapping personally.

[granit_silber]

I always use permatex spray tack gasket stuff ans never have any weeping.

never heard of gasket lapping personally.
Jeff,

hmmm....is that a standard procedure? Did I miss another step? I'm not to far from buying the plastic housing and RUBBER gaskets that accompany it!
-ashley

[uscharalph]

During the saga that has become my replacing the thermostat and assiociated gaskets, I came across some info and need some clarification.

I read that one should expect some seepage until a paper gasket has "lapped in"? What is lapping in and how long does it normally take?

I ask because I scraped all the junk off the housing and corresponding space on the block, reassembled everything, and I still have a small leak from the housing.

It does seem to be diminishing, but just wondered if I get to do this again.
-ashley
How bad is this leak. Maybe it's not the gasket, but the housing? Is it the aluminum housing or the plastic housing?

[granit_silber]

How bad is this leak. Maybe it's not the gasket, but the housing? Is it the aluminum housing or the plastic housing?
It's the BMW aluminum one. I didn't notice any cracks when I was scraping :)
-ashley

[uscharalph]

It's the BMW aluminum one. I didn't notice any cracks when I was scraping :)
-ashley
Well unless the housing is warped, it's not the housing.

[uscharalph]

I always use permatex spray tack gasket stuff ans never have any weeping.

never heard of gasket lapping personally.
I think we used Hylomar. You might want to read this post: http://www.bimmer.info/forum/showthread.php?t=12287&highlight=radiator

[Kalevera]

Ditto on what Jeff said regarding Copper Spray-A-Gasket to keep paper gaskets in place and help seal them with the block. I use the stuff all the time on pan gaskets and various housing gaskets. This is completely *DIFFERENT* from silicone/RTV -- RTV is very bad for cooling systems and bottom end bearings. Spray-A-Gasket isn't necessary, but it helps. I would only use hylomar on hoses, and even then -- it's not necessary. Just something that helps keep the seal tight (but too much of it will mess things up, as well). I only use the stuff on my car, not on the job. Good, aligned hose clamps are always a smart idea, though.

Also, one thing to remember -- use a new razor blade to clean the flanges, especially if they're aluminum. A normal gasket scraper, harsh pneumatic polisher attachment or similar device can seriously damage the aluminum, and the resulting nicks will cause leaks. With a particularly nasty water pump like the one I did on an S14 earlier this week, I spray the area down with brake cleaner to get things started, then start wiping away the gunk with a rag. Break out the razor blade to get the remnants of the gasket. One of the things that I use to help speed things up is a soft nylon/rubber whoo wheel attachment, which makes polishing this stuff quick and easy.

best, whit

[632 Regal]

for a minute there I thought I was so old school I missed some reason not to use that gasket spray crap....

Im not dead yet. Many i mean many years ago I had to deal with this stuff...back then the best stuf was the brown in a bottle and that didnt work, next was silicone which caused more problems than ever before.


Ditto on what Jeff said regarding Copper Spray-A-Gasket to keep paper gaskets in place and help seal them with the block. I use the stuff all the time on pan gaskets and various housing gaskets. This is completely *DIFFERENT* from silicone/RTV -- RTV is very bad for cooling systems and bottom end bearings. Spray-A-Gasket isn't necessary, but it helps. I would only use hylomar on hoses, and even then -- it's not necessary. Just something that helps keep the seal tight