Hi, everyone.
Has anyone had this problem before and how was it resolved?
Top Centre Vents blowing hot air even when A/C is in operation when in automatic mode.
Switch to manual and it eventually cools down to ambient outside temperature.
Lower, side and rear vents blow cold.

HELLLLLP!

 

Spudzfubb,

What have you got the centre vent "temperature difference" switch set to?

Paul

 

Could the heater valve in the engine bay have failed?

 

Hi Paul,
Thanks for getting in touch. Yes the top vent selector is in the cold position. As I said earlier, in auto mode even with the A\C on, it blows hot. In Manual it eventually blows cool.
I have taken the lower side vents off and the cowls on the tunnel to see if the temperature difference selector cable is operating correctly but being a Celebration it doesn't seem to have the mechanical linkages that the earlier MkII systems have, just what appears to be a black box of magic attached to the side of the heater assy.

Regards, Mike

 

Hi Vee,

Thanks for getting back. I'm not sure I know where that is fitted and how do you test it?

Regards, Mike

 

Mike,

You have the Delanair MkIII, but with the 1994 MY update.

If you can control temp by putting it to Manual mode, then check the key element which is sensing cabin temp when in Auto mode. That is the aspirator and in-car temp sensor which is located in the passenger side knee bolster panel. Carefully pull down the bolster panel and check that there is nothing blocking the sensor which may be giving a conflicting cold signal to the system and forcing it to blow hot air.

Cheers

Paul

 

That black box is the vacuum distribution manifold.
If you need one I have a good one.
PM. me for details.

 

Its in the engine bay, up against the firewall on the drivers side. It’s a brass colored metal part.

Replacing it is pretty straightforward. As a matter of fact, there is a plastic part that seems to work better than the very poor quality replacement part.

The part looks like this:
https://www.sngbarratt.com/English/#...&saveBranch=US

Im not saying the one SNG sells is cheap, or bad, but my experience buying it elsewhere was bad.

Ill see if I can find the alternative part number for the plastic one if you’re interested

 

Hi again Paul.
Thanks for the help, well I checked the cabin sensor and the little aspirator fan and no issues there with airflow etc. but the centre vents were still blowing hot. So what I tried was putting the sensor in front of the hot blowing vents to see if it would blow cold after detecting the high temperature and low and behold, it worked!
Have now refitted everything and all seem to be working fine. Go figure, classic cars eh?

Marion and I are coming down to Chatham from Scotland in the last weekend in May for a Naval Re-union. If you live nearby it would be nice to meet and say thanks over a beer if you like.

Regard, Mike