I have a 83 Mk1 Golf that has had a Passat VR6 engine conversion. All is coming along ok, apart from i'm now stuck on what to do regarding the coolant system. I believe the heating systems differ between the Mk1 and the Mk2/Mk3 in that the coolant is always flowing around the system with the later cars, but a flap within the airbox diverts the hotter coolant past the matrix. On the Mk1 there is an inline valve in the cylinder head hose that is controlled to allow coolant through the matrix or not. At present the previous owner has bypassed the MK1 heater matrix unit and joined the two heater pipes that come from the cylinder head and the auxillary water pump, thus meaning the heater is redundant. I would like it so that i can use the heater properly. The matrix delete seems to be the done thing when looking on VWVortex, but obviously they have better weather over there! My question is: Does the coolant have to be continuously flowing around the system, will it damage anything if i put the inline valve into the cylinder head hose that goes to the heater matrix? This will obviously block the flow when the valve is closed. Otherwise i will have to try and do something along the lines of my diagram below, and would it work?
What does the valve do? Does it close when its too hot and theres a risk or the matrix busting and burning your legs?
I've been trying to read about it today and learning whilst I go. Basically the standard mk1 has a valve on the cylinder head hose going to the inlet of the matrix. I guess coolant doesn't need to flow around the system with the standard engines. With later mk2 and mk3 cars there is no valve in the hose, instead there is a flap that diverts the air away from the matrix to allow cold air from the heater. My worry is that I've read that a constant circulation of coolant should go around the system, so am I going to damage my vr6 engine by using the valve that stops this circulation. If so, I'll have to try and use T pieces like in my diagram!
But the only part being shut out of the circulation loop is the heater matrix, (as per the standard Mk1 setup) so no damage to the engine is possible, as it still always has coolant circulating...
if you close the mk1 valve without the t pieces, coolant wont be able to flow from the head to the coolant pump, hence the need to fit the T pieces in a MK1. The std mk1 engines all have a heater bypass hose for this very reason, on the side flange you have a pipe that goes to matrix and another that goes from the flange to the metal coolant pipe
