Last month we found ourselves at the boneyard because of a stupid mistake I declined to mention. I guess it’s about time I swallow my pride. See that pipe above? It was once part of the heater core but in a moment of colossal idiocy I shucked it like an oyster, clean off.
Most old cars have little slider knobs controlling the cabin temperature. When you turn up the heat, they open the diverter valve, a Y-shaped pipe that routes hot coolant from the engine block into the cabin where it enters the heater core, a small radiator-like object. As the coolant snakes through the heater core, it emits the heat it carried from the engine up through the dashboard vents and into your face before flowing back to the cooling radiator at the front of the car.
Time has a way of hardening the sliders, and that usually means corrosion in the diverter valve is making it stick. We’ve known people who’ve endured petrified climate controls for years, but all you really need to do is douse the diverter valve’s insides with WD-40.
Unfortunately for us, Toyota uses a ridiculous clamp to attach one of the hoses to the diverter valve. It involves a cotter pin and a tightly wound ribbon of metal and is impossible to re-clamp inside the engine bay. The only option was to disconnect the end of the hose at the heater core, which had a normal clamp, and assemble it outside of the car.
But as you can see from the first photo, some overzealous clampsman on the Toyota assembly line went to freakin’ town on that sucker. The hose was squeezed so tightly that rubber spewed out like Play-Doh from a Fun Factory. And now, 23 years later, hose and pipe had fused into one.
But I had no idea, and the moronic thing was, while I was tugging on the hose I actually felt it starting to give way and thought, “Hey, it’s coming off!” Seconds later, a pop accompanied by a river of coolant. “Ha ha,” said Nelson Muntz.
Here’s what an unbroken heater core looks like. The protruding pipe ends are pretty soft and merely brazed on. Sadly, installing this requires taking apart much of the dash. That is no fun. But if there’s a silver lining in any of this, at least it happened while heater cores were still relatively plentiful in junkyards. The hose wouldn’t have been any easier to remove 10 years from now, and by then a move like this would really put me up a creek.
So, um, yeah. Don’t pull on heater core hoses.