Hi.
I recently changed the brushes in the heater pump on my 1998 XK8.
Before I did this the aircon was very cold.
I re installed, heater working well now, but there is practically no cold air now. The strange thing is, the air vents blow coldish, not aircon cold, but there is hot air blowing out of one side of the vent.
I know you will all say that it will mix and be luke warm, but that is not the case, its is outside temperature cold from most of the vent, but hot out of one edge!!
I bought, maybe foolishly, a DIY aircon gas top up kit. I have just done this, but no change, so I printed out the pipework connections to the heater pump, and also checked that I have reinstalled all the pipework correctly. I have!!
So, the impossible question, what is wrong?
In rural France, I dont have the luxury of loads of aircon specialists, just a renault main dealer who is.........not very good, to say the least.


Paul

 

What were the refrigerant pressures before you added R134?? Did you disturb refrigeration pipework during the repair?

 

To be embarressingly honest, I used a kit from a guys recommendation, and the instructions were as simple as open the tap, and empty the bottle of refrigerant into the system.
There were no specifics as to how much etc. I dont know anything about aircon (and neither does the local main dealer!!! hence me trying to do it myself)


Paul

 

I was wondering if the heater valve is not closing properly, and because the heater pump was not working previously, I didnt notice. Is there any way of checking if it is shutting off all the hot water?

 

Paul,

The first thing I'd suspect after disconnecting and reconnecting the A/C would be a leaking joint or O Ring.

The charge weight of R134 is critical. There is a Pressure Switch in the system which outputs a signal through the A/C Control Module to the ECM to disengage the compressor clutch if the refrigerant pressure is less than 2 bar or more than 30 bar.

The DIY A/C recharge kit I used on my XK8's has a pressure gauge which has to be first set to ambient temperature to deliver the correct charge.





Is the one you used a similar arrangement or just a can of R134?

Graham

 

+1 on Graham's post - but has the refrigeration pipework been disconnected? If so you can't just recharge-it must be vacuumed out first - any air in the system will cause excessively high discharge pressure not to mention moisture in the system and the damage that can cause if not removed promptly.

 

Hi.
Ive sorted it. I had a brainwave and took out the fuse that runs the heater pump. The air then is ice cold as before, until speed picks up, then there is a little warming. If I put the fuse back in, the air blows quite cold, so obviously if the pump is running it is able to constantly pump round hot water even when the valve is on cold. Voila! valve not returning to cold fully.
So, I probably didnt need the top up, although the pipes were not disturbed, and my kit has a gauge similar to those shown.


Thanks for all the help. Now to order a new valve and fit it before the trip from central france to italy for the mille miglia! (either that, or pull the fuse when its hot)


Paul