May I call you Vincent? This is a much discussed issue, under my name in the archives you see one theory dealing why heads leads and what can be done. Here's the abbreviated version. Thick cooling jacket gaskets are needed, and must stay pliable, to compensate for a reduction in clamping force as a result of dissimilar contractions of long steel studs and aluminum water jackets in cold weather, not an issue when the engine is at operating temperature. The need for an aggressive water pump to move the coolant through the length of the van and back. If you have an overnight cold soaked engine and the temperature is cold or below freezing and you then start the motor and then drive the engine at 3000 + RPMs before the thermostat opens, the pressure in the cooling jackets would be at a maximum when the clamping force of the system is at its minimum. Result, coolant gets forced beneath the seal. This coolant become corrosive and over time the heads pit. I also have the notion that the VW coolant contains an additive to keep the seals pliable or swollen or something that aids them is performing well.
I believe if you warm up commensurate with outside temps and keep the engine below 2000 Rpm, until the aluminum expands , you can alleviate this issue, I wait until I see the temperature needle reach the bottom of the first white hash mark. Sincerely, Mark Keller 91 Carat Cowichan Bay, BC. |
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