Replacement heater valve issues

[AndyWest41]

Hello all,
I have a strange issue with my replacement heater valve for my V8. I fitted it this morning and everything appeared to work fine - changing the temperature inside the cab made the motor rotate in both directions. However, having switched the ignition off and later restarted the car, the motor now doesn't move regardless of what temperature you set in the cab. I've checked the motor with a 12v supply and it moves without any problem. I've also tested the system for errors and none are reported. I took the motor off my old valve and tested that too but this also doesn't move when connected to the car but does move when connected to a 12v supply. Anyone got any ideas? It's really frustrating as it all worked to start with!

Andy

[black olive]

mm, pass, the only thing I could think of is an issue with the connectr that plugs into the actuator. you've obviously determined the actuaor is ok, and tbh they get a test before shipping anyway as I have to cycle them o set the valve position up. I can only suggest maybe a battery off disconnect in case anything is stored in the climate ecu

[Herman]

If the old valve doesn't move then the new one won't either.
I think the problem is with the controls, not the valve

[AndyWest41]

Thanks for the suggestions. The new motor did work when I fitted it and everything seemed to be fine until I cycled the ignition and now nothing. I've disconnected the battery for 5 minutes but that doesn't seem to have had an effect. Is there a way I can test the connections on the connector? If the aircon ECU had a fault, would this be reported by the diagnostic program (pressing 'auto' and 'air flow' buttons)?

One other thing - I set the internal temperature to 'LO' before changing the valve but when I turned the ignition on after changing, the temperature gauges read '22'. The motor still turned forwards and backwards and moving the temperature to 'LO' turned the valve so that the locking nut was at 12 o'clock (and turned the aircon compressor on). Adjusting the temperature back to 22 turned the valve about half-open. Everything therefore seemed fine. If the temperature did not set to 'LO' in the car before fitting the new valve however, would this have an effect on the motor? Would this effect be delayed until the ignition was cycled off and on? I think I'm just grasping at straws but it's annoying that it worked and now it doesn't!

[Malcolmr]

Andy. When you fit the new valve and set it up, it is not sufficent to just have the ignition on. You need to have the engine running as well. With the ignition on, and the temp set to lo, the valve actuator motor will turn clockwise when viewed from the left hand side of the car (which is actually opening the valve). If you turn the ATC control to hi, the valve will rotate 90 degrees anticlockwise (which is turning the valve off). But.... if you do exactly the same thing with the engine running, it will do the reverse. You may find that the reason it is not turning now is because it can't turn any further.

By the time I worked this out, I had completely lost the plot with where the actuator settings were, so I ended up taking the actuator off the valve and putting 12v over the motor pins until I was happy with where it was. I also marked off and on on the drive disc so I didn't forget next time.

I'm still playing with mine as the car is not cold enough in the summer and sometimes is still blowing hot air despite a lo setting.

Malcolm

[WNJ516]

I agree with Malcoms theory and have experienced a similiar "fault" ,and changed motors and valves to get over it, i think i have read on this forum that indeed you do need the engine running and set it up as malcom suggests and all should be OK

[Klaus]

Andy. When you fit the new valve and set it up, it is not sufficent to just have the ignition on. You need to have the engine running as well. With the ignition on, and the temp set to lo, the valve actuator motor will turn clockwise when viewed from the left hand side of the car (which is actually opening the valve). If you turn the ATC control to hi, the valve will rotate 90 degrees anticlockwise (which is turning the valve off). But.... if you do exactly the same thing with the engine running, it will do the reverse. You may find that the reason it is not turning now is because it can't turn any further.

By the time I worked this out, I had completely lost the plot with where the actuator settings were, so I ended up taking the actuator off the valve and putting 12v over the motor pins until I was happy with where it was. I also marked off and on on the drive disc so I didn't forget next time.

I'm still playing with mine as the car is not cold enough in the summer and sometimes is still blowing hot air despite a lo setting.

Malcolm

Same pain to me. After having fitted the new valve and checked working ok, it´s blowing hot air despite LO on panel. Battery off during my car in workshops for weeks brought no gain.

[Malcolmr]

Same pain to me. After having fitted the new valve and checked working ok, it´s blowing hot air despite LO on panel. Battery off during my car in workshops for weeks brought no gain.

Peter - during the hot Aussie summer, I find the best solution is to clamp off the bottom heater hose in the plennum (or better still, fit a manual tap so you can close off any flow of coolant into the heater matrix. It is the bottom hose which takes the hot coolant into the matrix when the three way valve is opened. Clamping it is the only sure way of keeping hot coolant out of the heater itself. You could clamp the middle hose, the one that comes from the right hand head on the engine, but you then restrict coolant flow to the other head which may have adverse consequences.

When autumn comes, I take off the clamp and let the ATC unit do what it thinks is best! In winter I also turn off the aircon compressor.

I am still working on seeing if I can move all the pipe work and the heater tap to somewhere outside the plennum to help keep the car cool in summer. There is a lot of very hot rubber pipe and metal work in the plennum which must add a few degrees to the incoming air! One of the collective recommended lagging it all, and in the end, that might be the easiest solution.

[Herman]

Not sure the pipe work is the issue in the summer.
The engine generates a lot of heat and that has to go somewhere.
Also the changed tunnel which puts the bell-housing almost in the cabin is not a big help.

I'm sure you'll get a bit of improvement insulating the pipes (or re-routing) but doubt whether it will sort the problem.

Let us know how you get on............

[WNJ516]

I think it's a design problem, i have fitted a new valve the heater hose from the valve was next to cold and I still had heat from the vents, i then fitted an internal non-return valve to the heater matrix return line, before it joins the valve bypass hose , this makes some diffrence but i still get slightly warm air which is a good improvement to as it was.
I have just had the aircon regassed and now i get cold air. but i have it in mind to change the valve position and type of valve, but i don't think it will get much better.
The air temp after regassing struggles to get lower than 3.9C but was better than 8.0C before, so the system is too small and the reasons that VMax 1000 gave, but every little improvement helps.