water pump leak - will fix myself - some questions
 

I've noticed a loss of coolant and a lot of white gunky deposit on the surfaces below the water pump. I can't see exactly where on the water pump it's leaking from, but I assume it's the seal.
This water pump and seal (and timing belt) is only 35k miles old, so i'm surprised it's leaking already. Unfortunately just 3 months ago I did a major accessory belt, coolant hose service that means i basically have to do the same labor over again. Anyway...

Questions:
1) I can get the whole water pump assembly for $77. Or i can get the forward half with impeller + gasket for $43. Which would you recommend?
2) I've noticed seals that look to be made of one material (paper?, rubber?) and others that are metal + rubber. Which is recommended? (The one i have now is metal + rubber and lasted only 35k miles)
3) For those that have done this, anything particularly difficult in changing the water pump (once you get the lock carrier and accessory belts off)?

Thanks!

Tom
'98 Audi A4 1.8TQMS
3)

Personally, I think the job was botched. Just get a new gasket, metal/rubber ONLY, and reinstall tightening the bolts down to the correct spec and making sure the sealing surface is perfectly clean.

Don't do the whole pump, its a PITA and not worth it unless those seals are leaking.

Thanks for that info. Some follow-up questions.

In order to remove the impeller housing and replace the gasket, does one have to remove the total water pump assembly or just the impeller housing portion?

Since I'm not 100% sure it's coming from the gasket between the impeller housing and rest of water pump, i'm going to have an o-ring gasket for between the water pump and engine block available. Are you saying the removing the rear portion of the water pump is difficult? If so, in what way?

Thanks again.