HELP - frozen my bits off tonight W163 no heat

[TechnoWhizz]

W163 2003 ML500

Hi All,

Just managed to get home tonight at -1 in the cab and seemingly no heat from the vents. All the aircon "seems" to be working. Lights are on, fan is working fine but no heat. Car is coming upto temp and is running fine. I just wish it had a defrosting windscreen! HRW is fine and Front screen defrost shows as working but no heat. Did I mention "No Heat!"

For the last 3 weeks most of my runs are only about 2 miles to and from work and the car doesn't really come upto temp in that time, nor does the LPG switch from petrol

Any ideas?

Cheers one and all.

Chris

 

[V6Matty]

Think this is something to do with the duo valve, not sure where it is on a 163 but I've read on here that a whack with the palm of your hand normally sorts it, maybe a knock with a hammer

 

[television]

54 is the hot air cold air motor, no duo valve on a 163 its all flaps, 54 could have failed.

 

[AMck]

Not too surprised about LPG not switching. In cold weather as we are having mine used to take about 2 miles to swap. It will depend on what temp has been programmed in the LPG ecu for change over - normally about 40degreesC.

Have you opened bonnet after your trip and felt temp of pipes going to vapourisor and heater matrix.
The vpourisor is normally plumbed in to the heater circuit, so could be both not getting coolant flow. If vapourisor mounted a little high, just a small drop in coolant level could cause an air lock.

 

[television]

If the engine is not getting past 70c, the heater will feel cold as its blown air.