T Reg Golf Heater problems

[johnm]

My son's T Reg 1.6 Golf suddenly stopped blowing hot air from its heater and started blowing cold. I'm mecganically competent but not familiar with the car so any poinyers gratefully received.

[Boardboy]

Have you checked the coolant level? If the heater matrix has no coolant in it will blow cold.
Regards Boardboy

[johnm]

The boy wonder assures me that the coolant level is fine, but I can't double check since he's in London and I'm in the Cotswolds :(

I'll just make sure he's looking in the right place he isn't very good mechanically.

[thefoolmccool]

Hi,

On newer cars there is one/two solenoid activated valves (not sure of the correct term) that opens the supply of coolant to the matrix when hot is selected. Over time these mechanisms can become jammed and fail to open. I have seen this happen before. To fix the problem I removed the mechanism and freed and cleaned the components as well as I could.

To find if your son's car has these solenoid(s) or not have a look a the back of the engine on the cars bulk head. There shoul dbe two small pipes entering this area close to each other. If the solenoids are included they will be around this area. They look like small cylinders about 2 inches long and about the diameter of an egg cup.

My car does not have these solenoids and it is a 1998, im not sure what year a T reg is however.

Failing this, you may have air trapped in the matrix, this is fairly common also. Try running the car quite warm and feeling the temperatuer of both of the hoses mentioned earlier. If either one is cold and no solenoids, then air trapped or matrix leak.

To try and free the trapped air, run the car with the expansion cap off and squueze the hoses for the matrix and also the main hose going into the cylinder haed. Try and rev the car at the same time (about 2000 RPM) and you should see bubbles coming out of the expansion bottle.

If this all proves unsuccessful, the thermostat could be gone meaning the coolant isn't getting the chance to warm up at all. Try taking the car for a long run up the motorway anbd see if the heat works then.

But my money is on the solenoid(s).

Kev