How clean is "clean" for the water pump mating surface?

[eremoy]

I recently did a water pump/timing belt change on my 2uz-fe. To my horror, after starting it up and driving around I noticed I was losing a lot of coolant from what I suspect is the water pump gasket. Today, I tore it all down and I'm ready to install the new gasket but I want to be absolutely sure it wont leak this time. I went ahead and bought a new beck arnley self-sealing gasket, even though the one that came with the aisin pump looked ok (also self-sealing.) Anyway, I'm looking at the mating surface and even after scraping with several new razor blades and sanding with 320, 400, 800, and 1500 grit sand paper for over an hour the surface is very smooth and all the old gasket material is gone but it still has a "ring" of what appears to be pitting from the old gasket. You can't feel it with your finger nail except very, very slightly at some spots. Should I go buy a dremel and a try to polish it out or should it seal like this? Edit: sorry about the mega pictures lol.

 

[Brian3676]

When I do T belt/water pump jobs and I find the WP surface has small defects like your pictures show, I usually put a very very thin coat of gray RTV on the engine. Works everytime. I would not suggest dremeling/polishing it, as you may create uneven surfaces, and that will basically be impossible to seal.

Also I know the ASIN gasket it metal, I am not sure if the other brands are. I would highly suggest not using the paper ones some aftermarket suppliers use, they suck.

 

[eremoy]

When I do T belt/water pump jobs and I find the WP surface has small defects like your pictures show, I usually put a very very thin coat of gray RTV on the engine. Works everytime. I would not suggest dremeling/polishing it, as you may create uneven surfaces, and that will basically be impossible to seal.

Also I know the ASIN gasket it metal, I am not sure if the other brands are. I would highly suggest not using the paper ones some aftermarket suppliers use, they suck.

Thanks, I'll give this a shot. The new gasket I have is the same metal style as the AISIN one so I think it should work.

 

[Brian3676]

Thanks, I'll give this a shot. The new gasket I have is the same metal style as the AISIN one so I think it should work.

Cool. Just be sure its super clean, no oil or coolant residue. I usually wipe it down with a rag and brake clean or something. Thin layer of gray RTV and it will last the life of the pump. If you got the AISIN pump they are good quality and I doubt there is any defect in the mating surface, but if there is you can do the same with RTV on the pump side.

 

[eremoy]

Cool. Just be sure its super clean, no oil or coolant residue. I usually wipe it down with a rag and brake clean or something. Thin layer of gray RTV and it will last the life of the pump. If you got the AISIN pump they are good quality and I doubt there is any defect in the mating surface, but if there is you can do the same with RTV on the pump side.

Will black RTV work as well?

 

[Brian3676]

I suspect it will. I don't use it often though. I usually use gray or Toyota FIPG. Black is supposed to be the same thing from what I understand, it just meets US auto maker specs and gray is more of the foreign auto mater specs.

 

[MSRP.]

How flat does the metal gasket have to be?
Mine was shipped over, and I suppose it was sloppily packaged as it has about a half inch valley due to it being squished.

Should be okay once torqued down to spec?