The water pump seal consist mainly of a carbon (or other material) ring
turning against some type of metal surface under spring tension. It is a
friction device that relies on the coolant for survival. The glycol alone in
coolant along with other additives takes care of this need. Running a water
pump dry and even using plain water does a number on this seal. Also, when
installing a new pump I like to let the coolant sit in there for a while
before starting the engine to allow the liquid to flow into those spaces and
the porous carbon.

I do not see the need for any additives especially soluble machining fluids.
Any antifreezes suitable for Diesel engines and a properly working pressure
cap eliminate the benefit or need of "water wetter" type products.

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Alistair Bell
Sent: Monday, December 19, 2011 10:21 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: replacements for phosphate-free coolant

What exactly in the water pump is this oil supposed to lubricate?

And what is the effect of oil on the rubber hoses in the cooling system?

Are there not corrosion inhibitors already in modern coolants?

alistair

On 2011-12-19, at 7:01 PM, Scott Daniel - Turbovans wrote:

> I add a small cup or so of 'machinist's cutting oil'...a water soluble
> oil you buy at a FLAPS that makes an excellent water pump lube and
> rust inhibutor ..