As of October 1st, 2022 the CLC has reduced the annual e-membership dues to $25. Non-CLC members in the forums, time to join and experience all the other benefits? See post in the General Discussion forum for a link to the Join page

Main Menu

'29-'30 Cadillac backseat heater grill

Started by john29cad, January 29, 2023, 10:33:10 AM

Previous topic - Next topic


I'm looking for any and all information pertaining to my '29 Cadillac backseat floor heater.  I have an accessory heater that's in the floor of my car directly behind the front seat.  The grill is all intact but its not connected to anything.  I spoke with a gentlemen from Santa Barbara that told me it was connected to a box that went around the tailpipe to collect heat off a hot tailpipe.  The goal is to fabricate a box that will go around the tailpipe and a connecter from the box to the grill.  Any ideas are welcome.

Chris Cummings



The heater you have in mind was the Kelch heater, and in their accessory catalogs, Cadillac called it their hot air heater (as distinguished from their hot water heater).  As you note, it worked by blowing air through a sleeve around the exhaust pipe, and there was an exit pipe from the sleeve to one or more registers in the passenger compartment.  If the items I have tried to attach come through, you will see a Kelch heater installation on a Packard.  The obvious dangers of using the exhaust pipe as a heating source for the passenger compartment meant that very few Kelch heater installations survived to the present day.  Hence I cannot show you a Cadillac example.  (My 1930 sedan was originally equipped with a Kelch heater, and all that was left of it when I got the car was a hole in the rear compartment floorboard. I have contented myself with installing a register in that hole as a conversation piece.)  From time to time, I have seen the blower for a Kelch heater offered for sale on eBay (though not recently).  Sometimes the floor registers show up there, too.

I hope that helps,

Chris Cummings

Johan Boltendal #158

Hi, from the fine car accesoires Cadillac 1930 , this is the way how it's done , JohanKelch heathing system.jpg

Chris Cummings


Thanks for weighing in!

Best regards,



Chris and Yohan:

Thanks for responding to my heater request for my '29 open Cadillac. I learned a lot from the information and pics you provided.  I found it interesting that there would be a floor register in a dual cowl phaeton, I can understand a closed car, but an open car seemed like a stretch.  My car has an emblem that signifies it was custom built so perhaps the heater installation was part of that.  I'm going to try and have a cannister fabricated to encircle the exhaust pipe and have an outlet built into it to direct heat via a flexible tube to the register. I don't think the electric fans were to prevalent in '29 for early heaters so I'll just count on gravity and hot air to push its way up there. 
Thanks again,


I would not trust anything like that, unless the
heat exchanger was welded up with very robust
304 or like stainless tubing, any air connections
far from the exhaust connetions. I believe some
aircraft did this.  Bruce Roe


Here are actual pics of my cars register both top and bottom side.


I have to agree that those heaters can be very dangerous if the exhaust pipe underneath the "cannister" should develop a leak.  Carbon Monoxide itself is an odorless and colorless gas, if there is a leak you may or may not smell the exhaust fumes coming with that leak and carrying the CO.  It would be neat to have that Kelch heater installed but I would never make it functional. 

It is indeed used to heat small aircraft and is a common way to get heat into the aircraft cabin.  This system in an aircraft needs close and regular inspections, especially in cold weather (or at higher altitudes) when the heater is likely to be in use.  When portable, battery operated, CO detectors became available, there was one in my aircraft at all times.  There was even an inexpensive detector using a treated disc about the size of a nickel that was to be stuck to the instrument panel that would change color if dangerous levels of CO were present.  They worked sort of OK but needed regular replacement to be half-way trust worthy.   
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2


Good analogy to aircraft heating.  Having an open car, I think we would mitigate some of the risk of CO, but then again the side curtains would make it pretty tight in there if I did make it functional, I would definitely have something to measure CO down by the register.
Thanks for the thoughts.