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WH Series II Statesman - no heat from heater - replaced valve already

parians

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Hi,

I have replaced the heater valve in the engine bay but still no heat from the heater (climate control). Is there any other blend motor/vacuum actuator that will stop heat? Fan works, motor gets to temperature, I can feel hot water at the valve (under bonnet). What other common things fail that may effect this? As far as I can remember the heater just stopped i.e. working one day not the next - it didnt slowly start getting colder so I dont think there is a blockage.

Many thanks,
PA
 

accentstencil

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Maybe no vacuum going to the thin hose that connects to the heater valve. Try operating it manually by pushing the lever on the valve to see if you get hot air then.
 

2O4TS

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The only thing that controls the flow of water to the heater core is the valve. It is vacuum controlled and on (open) by default so when you very first start the engine it takes time to build enough vacuum to close the valve.

So, Id check you have movement in the valve first because other than that a vacuum leak or blockage is the only thing that comes to mind. Once the car has not been running for a few minutes and the vacuum has all dissipated stick your head under the bonnet and watch to see if the valve operates when the car is started. It usually takes a few seconds before it starts to close if the heater is off. If the heater is off and the valve does not close then you either have a vacuum leak or a stuck valve. You can check the valve is operating by removing the vacuum hose from the end NOT attached to the valve and sucking on it. If the valve is functioning correctly, sucking on the other end will close the valve. If that works then you have a vacuum leak. That could be in a number of places so it then becomes a process of elimination. That should be enough info to get you started on the diagnostics.

Oh, the valve will get hot regardless once the motor has been running a while too. Even if it's not open, heat transfer through the hoses will eventually warm the valve/tap so that doesn't really tell you anything.

Edit: Just noticed you've already replaced the valve/tap. I should try paying attention to the entire post. 99% it's a vacuum issue.
 
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parians

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Hi 204TS,

Thanks - already checked and vacuum ok - I can see the arm moving. Is there anything under the dash like a flap that allows air to flow over the heater radiator?

Regards,

PA
 

2O4TS

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No, the flaps underneath the dash (inside the HVAC unit) only control where the air comes out and the "blend". Well.. sort of. If you have it set to "fresh air" then it will flow air through the heater but if you don't (recycle) but have the fans on hot air will still flow past the heater core. The only time it won't is with fan off and recycle on. If your fan works that clearly isn't the issue.

Basically, as soon as hot water flows to the heater core you'll get hot air somewhere. Having recently installed a climate HVAC from a WH Stato I spent quite a bit of time studying how it all worked. I noticed that if I didn't set it to recycle air and the heat was set to anything but cold I could feel warm air coming through as I drove and as I haven't had the air con gassed yet (I have a sensor fault I'm gonna get Tech II'd first 'cos if it's the sensor on the evaporator then the whole shebang has to come out again) it was getting pretty warm in there!

So what I'd do next is disconnect your heater hoses at the firewall and see if you can blow through the heater core. The pipes under the bonnet the hoses are connected to are your actual heater core inlet/outlet. I guess you could stick a hose in it but be prepared to get sprayed particularly if you have the hose cranked and a blockage. Doing that will certainly determine if you have a blockage or not and pretty easy to do.

You can touch the pipes inside the car up under the dash. I know 'cos I burnt myself on them fiddling with mine when I first installed it and had vacuum issues. That's a sure fire way of knowing there's hot water getting to the heater core!
 

parians

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No, the flaps underneath the dash (inside the HVAC unit) only control where the air comes out and the "blend". Well.. sort of. If you have it set to "fresh air" then it will flow air through the heater but if you don't (recycle) but have the fans on hot air will still flow past the heater core. The only time it won't is with fan off and recycle on. If your fan works that clearly isn't the issue.

Basically, as soon as hot water flows to the heater core you'll get hot air somewhere. Having recently installed a climate HVAC from a WH Stato I spent quite a bit of time studying how it all worked. I noticed that if I didn't set it to recycle air and the heat was set to anything but cold I could feel warm air coming through as I drove and as I haven't had the air con gassed yet (I have a sensor fault I'm gonna get Tech II'd first 'cos if it's the sensor on the evaporator then the whole shebang has to come out again) it was getting pretty warm in there!

So what I'd do next is disconnect your heater hoses at the firewall and see if you can blow through the heater core. The pipes under the bonnet the hoses are connected to are your actual heater core inlet/outlet. I guess you could stick a hose in it but be prepared to get sprayed particularly if you have the hose cranked and a blockage. Doing that will certainly determine if you have a blockage or not and pretty easy to do.

You can touch the pipes inside the car up under the dash. I know 'cos I burnt myself on them fiddling with mine when I first installed it and had vacuum issues. That's a sure fire way of knowing there's hot water getting to the heater core!
Thanks 204TS -I'll test further to see if there is a blockage

Regards
PA
 
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