Warning: Heater Valve Check

[biggles copilot]

Just a note to remind owners hoping to drive their pride and joy over the winter months.




Yesterday, having replaced the hardtop, I decided to go for a drive along my usual 12 mile warm up route to check for squeaks and rattles. Half way through the journey I switched the heater on. Within a matter of minutes my left foot, which was on the footrest, got very hot and wet. I was losing water at a tremendous rate and to cap it all the windows steamed up. Once the panic had subsided I 'high tailed' it for home getting there just before the needle went into the red.




After spending what seemed like the whole afternoon clearing the coolant from the footwell with roll after roll of paper towel I investigated the cause of the problem. The leak seemed to be from the heater valve which was confirmed when I operated the lever on the dash, the whole body of the valve rotated. The valve had seized and this could only have happened over the summer as it worked perfectly last winter.




Now the task of stripping the dash and console to get at the heater and replace the matrix. Oh Joy.




I forgot to listen for squeaks and rattles.

[Phil S]

Mine is stuck in the hot position, roof down...on problem....winter it's good, will fix it one day, but more pressing jobs first.
Phil

[biggles copilot]

Know how you feel. I hate doing any work on the cooling system. The damn coolant goes anywhere but the container I prepare.

[KOY 23]

My advice is to free off the heater valve as soon as the temperature slider starts to stiffen up. If you leave it, the clip holding the outer cable in the centre console will come off damaging the cable. The clip is a so and so to replace and you still have to repair the valve,

[STypeR]

If you are using the same valve make sure you polish it up with some very fine steel wool and make it nice and clean and I would probably use a marine grade grease as well which may help future seizing.. Check the correct screw has been used that holds the lever and that the threads of the valve are okay to be able to hold the screw. I think to memory it is a 10x32 screw. Hard to get good torque on it as a Phillips head and an Allen key style head does make more sense in this tight application. Also make sure you are a good contortionist!

[macstag1]

My heater valve stuck this spring, the coolant had been drained over winter whilst I replaced timing chains etc. got the the valve freed up but then the control lever didn't work. So next job on list is too sort that out. I realise I will have to remove the central console to get to the controls, any suggestions as o how best to tackle that one?
Cheers Mac

[DJT]

Or you could just leave it in the HOT position and, when necessary, shut off the hot airflow using the RH heater control. My heater valve works, but it is only shut off occasionally to exercise it. Even in Summer, when the heater matrix gives extra coolant capacity.

[mole42]

Bad luck. I’ve escaped that problem with my Stag but I do remember it from a 2.5PI years ago.

I have found that removing the drivers seat (RHD models) makes the heater repair job much easier..

[biggles copilot]

Managed to drain the remaining coolant from the block. Took me all afternoon to get one of the block drain plugs out; what a pain to remove. I decided not to touch the offside plug but instead, jacked up the offside to get as much of the coolant removed s possible. Tomorrow I start on the dash and console.

[brian0443]

Removing the dash, console, and heater assembly is a tedious, but not overly difficult job and a few hours should see you getting close. One thing not mentioned normally is that the drain tube from the bottom of the heater casing. passes through the transmission tunnel. You need to wriggle the assembly up to get it to clear the tunnel before you can lift out the heater. It will probably at some previous time have been well sealed with some kind of mastic which will have quite a grip on it. Otherwise, it's time, patience, and a bit of good luck.
Brian

[macstag1]

Thank you all for advice, I shall tackle the job sometime next week, I do enjoy a challenge provided there is no time pressure, hopefully will only have to remove console to be able to reconnect the outer cable. I will report back on progress.
Cheers Mac

[Niss]

I am new to classic car ownership and it took me a week to remove the dashboard and rebuild the heater unit and refit. I am not a quick worker though.

[biggles copilot]

Thanks Brian for that piece of advice. As you say, doesn't appear to be mentioned anywhere.

[Klaus Schlueter]

If this is of any help to you: Stagwingnut posted on 14th June 2014:

"I had my dash out recently for heater replacement, I noticed how much easier it is to access the wiring, remember the dash wiring can be unplugged by removing the speaker cover, dash comes out with its wiring still attached to all the dials!! So dash out is recommended!! Rgds Graham"

Klaus

[Klaus Schlueter]

And this one: