Heater box detail on 120 OTS

The XK120 I am restoring was originally optioned with a heater. This was before they came standard in late 1951. I believe the heater control switch should be on the panel in front of the steering wheel, so that is where I am planning on putting it. But, my question is in reguards to the heater box itself. The box has an outlet “T” for providing air to the defroster outlet vents on later cars but this car being early 1951 has no defroster vents at all. Should the “T” be capped on each outlet of the “T” or should the whole “T” be removed and a cap fabricated to replace it. Or should this have a heater box that is completely different with no defroster outlet at all. The heater box I have to go in the car was sourced from e-bay as the car came with no heater in the boxes of parts. Thanks for any help you can give.

I had the same problem. I capped both ends of the T with rubber caps. I believe there was a blanking plate for when no T was fitted, but I’ve never seen one. Does anyone know if such a thing is available?

The rectangular opening in my (very original) car had a basic sheet metal plug/insert whose sides were bent at right angles such that they fit tightly inside the opening. It was held by one or two small sheet metal screws.

Several years ago, BruceG posted this photo of the blanking plate for the “pre-defroster” Smiths heater supplied to his XK120.

That’s what I was thinking. Thank you all for responding. Doesn’t look hard at all to fabricate and will use the same 2 small screws that the “T” is currently using.

Thanks for posting again, Mike. I guess finding one would be well nigh impossible, but I can make something that will do the job.

the rheostat was on the alloy dash to the left of steering wheel column on LHD car and to right of steering column on RHD car

Thanks for confirming that Terry. I have seen one period picture showing the switch in that location and my dash has a hole there (although there are a few other random holes there as well). When I recover the dash I will use one of the holes for the heater and another for a turn signal indicator, as I am converting to those new-fangled flashing lights that are all the rage.

Hi Jim my car also has a heater or so I
I think . On the left side of the dash is a heater switch , I just looked at the dash today and seen the switches. Everything I have been reading tells me the heater shouldn’t be on the car.

They were an option on the earliest cars. Mine has it noted on the heritage certificate so I know it was not just added later in life. I made the block off plate today, just need to paint up the block off and face plate so I can re-assemble it.

Interesting, I have a heater box that came with my car , I got the heritage certificate heater is Not listed on it . I am thinking because of coved 19 they may not of done a proper search . Here is my email kevinjcarlaw@gmail.com Maybe we can send photos to compare cars.

Sure but I will post them here so i can be a reference for others if need be and the group can chime in if any of my pictures differ from when the heaters became standard equipment. There may be some small nuances that changed. I’ll take some pics tomorrow and post them. I am putting the heater back together tomorrow as well so it is not installed in the car yet.

Here are some pics of the heater box. As far as I know it is a factory modification done as an add on option.

Here is the heater assembly after I tested it and then mounted temporarily. Interestingly it did not make a difference which way I did the polarity, the fan spun the same direction.

Great information JIm thanks for sharing.

Is your heater install similar. I am curious why no listing on the heritage certificate. But if it looks factory like on this car they must have not noted it for some reason.

The heater motor was in a box when I got the car . The holes on the firewall were drilled and ports open on the motor . I would really like to know if it was factory, thinking of emailing them to check heritage certificate. I was also told for a extra fee they will send a photo of the hand written leger of when the car was built. Also the brake drums on the car are chrome , just check are they on your car.

Definitely not chrome. I was under the impression that on cars of our era if they did not come from the factory with the heater option, then they did not have the heater box welded into the car. They would have had just a flat panel from the fuse box all the way across to the wiper motor and not the raised box to accommodate the heater.

Thanks Jim this information is a big help.