'57 Bel Air Heater Core
I usually don’t work on other people’s cars. On rare occasion, I do make an exception. This article documents one of those exceptions. My dear friend Carol has a few cars and thoroughly enjoys driving them to shows and cruise nights. Since her husband passed away a few years ago, she needs a hand with repairs and maintenance every once in a while. Don’t get me wrong, this little old lady knows her way around the garage. She’s an excellent help with handing and finding tools and knows more than most of my buddies do about hot rods.
Last summer my son and I helped her put a new alternator on her flathead powered ’47 Ford tudor. It was then that she mentioned a massive puddle that had formed under the cowl of her ’57 “no-post” more-door while it sat in storage. I was 95% certain it was the heater core leaking but you never know. I didn’t want to sign on for an afternoon job and find a frost plug or other more severe problem.
When we got to the storage building I was able to confirm that the anti-freeze tested fine (probably no freeze related damage) and that the leak appeared to be emanating from the lower hose nipple on the heater core. Cool. So I looped the heater hoses to cut the leaky heater core out of the equation, topped off the coolant and we went to work on getting her started and to my place to work on.
That’s when I discovered the other little problem that had developed over winter. The fuel pump wasn’t getting any gas up to the carb. Even with priming the float bowl and running the engine, the pump wouldn’t pick up any fuel from the tank. I guess we’ll need to put that on our list too. Eventually I was able to prime the pump itself with some fuel and got it started. See the next article for that adventure. I don’t want Carol stranded somewhere with a dead fuel pump.
Once we got the old hardtop to my place I made a list of items that I’d need to complete the job. I also made some calls to see how much it would cost to have the heater core re-cored, sealed and pressure tested. To my surprise, the Radiator Shop in my city said that they no longer repair radiators or heater cores. The guy who specialized in that work was no longer working there as there wasn’t enough work to keep him busy.
All the new radiators are aluminum and plastic, they just scrap them when they’re leaky. So, I called another shop in Omaha and they said that they could look at it and if it was repairable that they’d be a week or two. That settled it, I picked up my catalog and placed an order for Speedway's 1957 Chevy Car Heater Core, part number 91734460 and as a precaution I also ordered their Heater Core Mounting Plate, part number 91734461. Chances are, if the core has been leaking, this plate will be pretty crusty.
These cars are about as simple as they come. It’s such a pleasure to work on tri-five Chevys. From an era when engineers still considered the people servicing the car later on. The heater core is completely accessible from the engine bay. The cover baffle is secured by two sliding clips.
Something to note on ’57 passenger cars, they were available with two different types of heaters. Deluxe and Standard. You can quickly identify which you have based on whether the inlet and outlet are offset in opposite corners or together on the same end. The offset version is the Deluxe heater, which is what is in this Bel Air. There are other major differences in the systems are regarding where the blower is located and how much under hood duct work there is.
While the radiator drained I began disassembling the front side items like the blower motor, plenum boot and eventually the heater hoses and the plenum itself.
Once the sliding clips are in the full-up position, they will slide off the studs. In theory, the plenum along with the heater core and mount plate will all come out as well. What I discovered in this case was that the unit as a whole would not clear body brace at the lower outside corner. It took a little jostling, but I was able to separate the plenum from the mount plate and take it out in parts.
Duly noted. I need to reinstall the core and plate first, then tuck that corner of the plenum in and rock it into place. So much for those generous GM engineers.
The reassembly process was pretty straightforward and in reverse of the tear down. I reused the seal the was between the mount plate and firewall. Between the plenum and mount plate I applied a bead of black RTV silicone sealant to ensure the next guy had just as much fun as I did separating them later. After everything was reassembled and refilled with a fresh 50/50 mix of antifreeze I checked for leaks. I did this again after the engine was warmed up and the heater valve all the way open.