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TR2/3/3A new water pump dry run - TR3A

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NutmegCT

NutmegCT

Great Pumpkin
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Just finished replacing my failing water pump with the combination pump/pulley from VB. Thank you Randall for all the advice!

Some sources (not VB) say to run the engine without coolant for a minute, to "break in" the pump. Some say to spin the pump with a drill before assembly. Some don't mention a break-in at all.

So do we or don't we? Why - or why not?

I haven't added the new coolant yet.

Thanks.
Tom

PS - I've got a brand new pump to housing gasket (VB #1-694) and housing to block gasket (VB #1-697) I don't need. Free to first request for postage only.
 
The theory is that the face seal used in the water pump needs a chance for the two surfaces to "bed in" against each other in order to fully seal.

However, they seem to bed in just fine with coolant in the system. Possibly it takes a little longer, but I've never seen more than a few tablespoons weep from a new pump. And improved manufacturing methods on new pumps may well result in seals that seal right off the bat.

So, unless the water pump came with instructions to run it dry, I wouldn't bother. Likely it wouldn't hurt anything if you want to do it, though.
 
Aloha Tom,

A few years ago I put on new water pump from VB. I didn't spin it dry before installing it and have not had a problem with the pump or any leakage.

I rebuilt the water pump on my MG TF about ten years ago. The rebuild instructions included the warning to turn the pump dry to lap in the mating surfaces of the water seal and the pump housing.

I would think that if you needed to lap in the water seal but spinning the pump dry there would be a warning included on the packing slip.

If it would provide you with peace of mind you can do it. About 30 seconds is all it needs.
 
On older pumps that may have a carbon face seal, dry spinning will help in mating the surfaces. With modern seals that have ceramic or sintered iron surfaces, this procedure is unneccessary. Carbon faced seals went out of vogue in the '50's.
 
Art-

I don't mean to butt in on this thread, but
I'm doing a water pump project myself.

When Paul's three water pump nuts and lock washers
arrive next week; I will install the new water pump.

I also have a new gasket. Do I need to apply any
gasket sealer like I did with the head gasket? I still
have that bottle of airplane sealant TRBill recomended.
It worked great.

thanks,

d
 
I all ways use a sealnet on water pump mating surfaces. I have changed the pump twice on my TR6 and neither have leaked at the gasket mating surface when I used a sealent. The one on the car is about 25 years old and no leaks. Permatex is the brand I used because I had it on hand; I think most any (major)brand will do.
 
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Dale,

I primarily use a thin application of,

Permatex Clear RTV Silicone Adhesive Sealant

It also comes in blue but if you use too much you will see it in the seam and I don't like the looks of that so I usually prefer the clear.
 
FWIW, I much prefer Hylomar to classic Permatex (shellac) or silicone sealer. They all seal quite well, but the Hylomar stays soft forever, which makes it much easier to clean up next time. Frequently it even allows the gasket to be reused, but IMO it's worthwhile just for the easier cleanup.

With silicone, it's easy to use a bit too much, so it squeezes out of the joint. That's no problem (other than appearance) on the outside, but on the inside it can sometimes break off into strings of hardened material that can then find their way into places you don't want them (like clogging a radiator tube). Not very likely, I know, and most people will never have a problem (or at least never know they have a problem) with it. But as I see it, why take the chance ? I have disassembled units (like the Volvo J-type I took apart a few months ago) where someone else's silicone job had plugged things up inside.

BTW, Hylomar was developed by Rolls Royce, so their cars wouldn't leak. It's gotten harder to find in the US, since Permatex quit making it, but IMO it's worth seeking out.
 
Dale, Yes, a light coat of sealant is a good idea, make sure you have the engine side scraped clean, razor, x-acto knife, etc, with no scratches in the metal.

Permatex has come out with a new little tube product especially for water pump/thermostat outlets.. So maybe your local Pep Boys, Checker, whatever, has it in stock now.

Oh, by the way, Hylomar is getting very difficult to find. So if you do find some and want to return to 40-50's sealing technology, rather than modern chemistry and engineering, buy a package or two.
 
If I might just grab the thread back for a quick second ...

New pump is working just fine. New Prestone 50% solution, fifty mile drive, no "dry run break-in", and no leaks! (and no special sealant)

And the engine sounds quite different (can you say "really smooth!) without the old water pump clatter.

Tom
 
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