Car heater problem

[KarlBristol]

My heater has never worked properly since I owned the car, and as the car is a daily driver and the cold days are quickly setting in its something that I'd like to sort out once and for all.

In short I've got two issues. Once the car has been running and is up to temperature the heaters when on hot will blow air that can only be described as mildly luke warm at best. Also the slider for the heater temperature control will not go all the way to the left hand side, it feels like its stuck on something. I've had x3 different heater unit/fascias in there and all three have had the same issue.

My main concern is getting the heaters blowing out very hot air...
Is there a flap system behind the dash which could be broken?


Some facts that might help to diagnose it:

There is no coolant issue/blockage
The car has had x4 coolant changes and x2 different engines
There is no thermostat or car temp issue
The heater fascia section itself has been replaced x3 times and works
The blower speeds work fine
Peter ran a coolant flush and got out some silt from the system
I've previously run a coolant flush
The system was bled again the other day and is ok
The heater matrix is still faultless
The pipes running into the car for the heater get scaldingly hot indicating that they are doing as they should

I'm pretty sure it's an issue between the back of the heater unit and the pipe work in the frunk. Maybe a broken or loose connector somewhere.

Has anyone has similar?
Any ideas?

[Torero]

Karl,

I've had a similar problem and no solution as yet but over the next month I'll be digging a bit deeper on it and get back to you.

However, I would start with the slider cable, the loose end needs to be pinned onto the top of the heater unit with a circlip type locker and then it needs to be secured again by a metal clip which is at the rear. This clip is what holds the cable to the panel so that it doesn't just rotate on the circlip (if you get my drift) when operating the slider. If this clip is not in place or if the cable has movement within it then the flap will not open fully.

Check the clip first and then I would also try pulling the cable by hand to ensure it moves all the way otherwise it's just 'mixing' hot and cold air if it's opening part way. Worth a look and as always it's best to start with the basics.

Also, when bleeding the air from the bulkhead in the frunk, using the clear tube, ensure that the tube is elevated. It's best to hook it to the bonnet clip when opening the valve as the air is lighter it should ensure that it dissipates easier, although I would think with the amount of work done and knowing that Peter has been involved, that this has been carried out already.

Hope that helps.

John.