Heater Fault 89 V12

[Flappers]

Hello, the heater takes an age to blow even warmish air out, I'm found warming my knuckles after 20 min behind the wheel. I mentioned it to a chap at a show last year and he said its allmost certainly a vacum problem but then he was dragged off by his kids and we never got to talk more about it. He pointed to a unit on the bulkhead and suggested a kink in the hose or a split somewhere.... I can hear the blowers moving parts doing there thing, but thats about it, cant offer anymore explanation. The Air Con worked briefly 4 years ago the summer I bought the car but has never worked since, not sure if thats related ... Can anyone suggest what i can do to fix it please ?

[stevewarbs]

Hi Sam, your car is much newer than mine so I don't know if the system is the same but the first thing to check is whether you have hot coolant going into the marix. if not, check the water valve if you have hot in and cold out then try bypassing it.

HTH
Steve

[mike020150]

The operation of the heater/aircon unit is quite complicated so start with the simple stuff. If you have never changed the engine thermostats, change them (2 of them) for new ones of the correct temperature range (88 degs for later V12s). Then, as already mentioned, check the heater pipe temperatures before and after the water valve mounted on the engine bulkhead. The heater controls should be set to full heat and the pipes checked to see if they are both equally very hot. If OK that would mean the heater valve is opening and both it and the vacuum controls are OK. If not, check if valve moves freely when you suck on a tube attached to its diaphragm housing. Next, after replacing any faulty water valve, check that the other (heater return) pipe is hot. If it is only cool, it's likely there's a reduced water flow through the heater matrix which could be cured by replacing the matrix (not an easy task).

Should none of these things solve the problem, it's going to be an issue involving the operation of the heater unit air flaps. It could be electrical, mechanical or vacuum related. Often, the biggest problem is access to any of these problems which are best tackled by someone who knows and understands how these units operate. Mike.

[Flappers]

Thanks for your help chaps, I'll go look for diagrams