I had the same problem with the 4x2. Luckily, I was having the bakkie resprayed at the time and they had already stripped the dash board, so it was no big sweat to remove the heater and repair the pipes, which had begun to break loose at the joints rather than corrode.Choppie wrote::D
The water leak is caused by a small hole in the copper pipe going in to the cab underneath the dash......
If I can not get it fixed from the Engine compartment I will have to go without the heater as...there is no way I am taking the dash apart.. .. but I am sure I will be able get it fixed....
If anybody has a heater that they will not be using, I would be very grateful for the heater shut-off valve, the one connected to the hot water hoses in the engine compartment, on the firewall. I cannot find one anywhere and the current one I am using is from a Golf and simply does not have enough travel to fully open or shut.
-F_D