1977 Royal Monaco heater control valve not closing?

[Ambivalence]

I’ve got a mechanically completely stock 77 Royal Monaco (yes, I converted it to a Bluesmobile).

360 2BBL AC car.

I finally took it for a shake down ride and I noted that I’ve got heat coming through the vents no matter what position the temp slider is in. Fan kinda works but sounds like a dying porpoise.

I see the heater control valve is vacuum operated and is spring loaded in what looks like the open position.

What’s the troubleshooting process look like?

I know I can cut in a manual valve, but I’d prefer to keep the stock components if possible.

Thanks!

 

[Gerald Morris]

I’ve got a mechanically completely stock 77 Royal Monaco (yes, I converted it to a Bluesmobile).

360 2BBL AC car.

I finally took it for a shake down ride and I noted that I’ve got heat coming through the vents no matter what position the temp slider is in. Fan kinda works but sounds like a dying porpoise.

My heater fan sounded the same when I got the car we drive now, but after running it on "Super" for a little while, it started blowing well. If the thing sat for some time, its likely just rusted and crapped up.

I see the heater control valve is vacuum operated and is spring loaded in what looks like the open position.

You might, for the short term, manually close the thing and disconnect and plug the vacuum line. You could also get something like a MightyVac pump, attach that to the control valve and see if it still works. It likely doesn't, but LOOK.

What’s the troubleshooting process look like?

Find an FSM for that ride.

I know I can cut in a manual valve, but I’d prefer to keep the stock components if possible.

Thanks!

 

[WissaMan]

I just uploaded and linked the 77 chassis/body FSM in the Fuselage forum. I'll be uploading the electrical manual soon and also the tech bulletins.

 

[Ambivalence]

I just uploaded and linked the 77 chassis/body FSM in the Fuselage forum. I'll be uploading the electrical manual soon and also the tech bulletins.

Can you link me? I don’t see your post there.

Thanks!

 

[Gerald Morris]

Can you link me? I don’t see your post there.

Thanks!

I hope for your sake that you FIND an FSM for that Royal Monaco. I searched for a free pdf for you, to no avail. This reminds me of Why Gerald Won't Buy a Formal C-body Mopar. Best of Luck to you.

 

[Big_John]

Can you link me? I don’t see your post there.

Thanks!

I hope for your sake that you FIND an FSM for that Royal Monaco. I searched for a free pdf for you,

Downloadable 1977 factory service manuals? If not, maybe I can provide.

 

[Gerald Morris]

MyMopar was my FIRST stop for this. No bueno. That link might be of some use....

 

[Ambivalence]

Thanks!

I tested the valve itself and it works under vacuum. For some reason, the slider to go from hot to cool is not sending vacuum its way.

 

[Gerald Morris]

Thanks!

I tested the valve itself and it works under vacuum. For some reason, the slider to go from hot to cool is not sending vacuum its way.

Hmm, probably the works behind that slider are rusted and dirty. Spray some penetrant stuff in there, see if you can work it a bit. You can always disconnect the vacuum valve from the wire or lever it pulls on, manually close it, tie it off w something for now, and take your time repairing things without hot air coming through those registers anyway. On my '66 Newport, I would work my heater after disconnecting the vacuum controller, though I know the slabby heaters were a LOT simpler in design.