Hi all ,
After running the car upto temperature to tweak the aav, I spotted smoke coming through the front screen vents. In a panic I disconnected the battery and then realised there was no burning smell. The smoke was actually steam. So I'm guessing something to do with the heating system. I'm unfamiliar with this area, particularly behind the dash. Any ideas on what its likely to be and how to access the area. Also is it possible to clamp the pipe off in the engine bay so i can still drive the car.? Many thanks in advance

 

Brinny
This might be a heater matrix leaking.
Pressure test the system cold (pressure test kits are cheap on amazon). If it is I think, repeat think, it is possible to replace the matrix without having to remove the dash.
If it is actually the evaporator leaking, which it might be if the "steam" does not small of antifreeze, then it is a dash out job. Do-able, but a ROYAL pain.

 

Cheers Greg. Cars off to Andy next weekend so I'll see if he can sort it.

 

If you have functional a/c you might get some fogging of the windshield if the humidity is high. I would watch your evaporator drainage for coolant (the puddle under the car after the a/c has been on).
Kirby’s book says you can change the heater core without taking out the dash on Delanaire III, which I believe all your cars have.

 

Thankyou for your help, I hope you are right!

 

The Del III heater core is vastly easier to replace, yes. Unlike the Del II system, the entire HVAC case remains in place. The heater core slides out of the case via a little access door. Remove the glove box and instrument cluster is basically all you have to do to gain the needed access.

The Del III system was introduced in late calendar year 1986 and the fastest way to identify which system is in place is to simply look at the temp control dial. The Del III has the "Pull for manual control" feature. The Del II does not.

Cheers
DD