W126 Water Pump Installation Questions

[zymurgist]

I'm kind of a noob when dealing with aluminum engines. What's the best way to get the old gasket material off the engine, termostat housing, and top water outlet? Should I soak them in solvent and use a plastic scraper? My normal M.O. is to use a steel scraper and plenty of muscle, but that's for Chevys with iron blocks. I fear that I would damage the machined surfaces if I did that on the Benz.

Also, should I be using anything on the threads of the bolts that hold the water pump in place? I typically use black silicone on the iron block Chevys.

[psfred]

What engine?

Usually, the water pump seals with an 0-ring on the newer engines, but I'm not sure on the aluminum V8s, could still be a gastet.

If so, use rubbing alcohol, the sealant is usually something like Permatex. Do not scrape with a steel implement, you WILL gouge it badly! I use Aircraft (red painton) Permatex on everything like waterpumps, it's eaiser and seals better. Make sure you completely coat the gasket, sometimes they "melt" if coolant gets to the gasket material and you DON'T want to do this job again just for fun!

Use NeverSieze or something similar on the bolts going into the block so they won't stick, bolt sealant isn't necessary. Coat the shaft of the bolt a bit, too, so it won't stick in the water pump, either.

If there is an o-ring seal, put it in dry after getting the block completely clean. If you use sealant, you normally cause leaks because the sealant will set up before the o-ring "seats" completely. Same reason you don't use sealants on the old "lace" window gaskets.

You may need to use some vinegar to get calcium deposits off the block. Use scotchbrite sparingly, too -- you can grind enough material off to cause leaks if you get carried away!

Expect to replace a bolt or two on the thermostat housing of it was leaking at all, the bolts are small and sieze pretty easily.

Peter

[jbaj007]

As per Peter..."Expect to replace a bolt or two on the thermostat housing of it was leaking at all, the bolts are small and sieze pretty easily. "


Amen, brother. You may want to acquaint yourself (check archives) with some of the techniques for dealing with the broken bolt. The new Sears left hand stud "socket" (for those with a bit of shaft still available) and/or left hand drill removers seem to be the current favorites. I wouldn't worry much about it, because odds are yours won't break, but it will give you peace of mind to know that others have always succeeded in removing them, one way or another.

[zymurgist]

I've been away from the project for a few days, but I worked on the water inlet housing last night... it's the piece that bolts to the top of the water pump and connects to the intake via a short hose. I tried all my nasty solvents and couldn't get all the old gasket material off. I scraped ever so carefully with a razor blade and got it down almost to the metal, and tried the solvents again. Nothing. I tried using a polishing buff in a die grinder and all that did was make the gasket remnants smooth and shiny. I haven't even started on the engine yet (it uses a gasket, not an O-ring seal).

The one thing I haven't tried yet is alcohol based solvent.

[WANT '71 280SEL]

Have you used paint thinner yet? I find it useful, and psst, don't tell anyone, but I have used a steel scraper that was made for scraping off gaskets on aluminum engines. You do definitely have to be careful. I do like the paint thinner though, it works well.
Thanks
David

[Mike Murrell]

Should you wish to use a chemical gasket remover, Permatex makes a fairly good one. It's available at a lot of auto parts stores.

Be careful not to get this stuff in your eyes.