Heat exchanger question

It's not often the heat exchanger themselves that are at fault, but the joints where they meet the rest of the exhaust system. The exchangers themselves are pressurized whenever the engine is running (coincidentally, that's also the only time there's exhaust gas available ;) ) so any leak within the heat exchanger housing would be clean air leaking OUT.

More or less the only exception would be at the very end where there's lower pressure, perhaps even vacuum, when the fan shroud pipe enters the heat exchanger. That's also where the most common leaks are, at the doughnut seal between heat exchanger and muffler. (or header system if so equipped).

One place where the exhaust gases are sure to enter the heating system, is from the engine bay. If exhaust gases get in there, they will surely get inside the car too since the fan is in the engine compartment. So make sure your engine bay seals are intact.

Jan

Jan

Wow -- I am glad I asked! That the problem is more likely to be at the seals had not occurred to me yet. Also regarding keeping exhause fumes out of the engine bay is obvious to me now, but only after you mentioned it. :) I'll be sure to pay close attention to all the seals when I put it all back together.

Being new to bugs, it may not a bad idea for me to drive the bug with a canary(*) in the pasenger seat for a while, huh? :)

Appreciate the tips. Remco

(*) maybe a carbon dioxide detector -- canary sounds funnier, though.

(*) carbon monoxide, that is -- my chem professor would have slapped me on the head just now..

Are these on a FI engine?

RT

LOL

you'll have PETA busting your balls in no time ;)

Jan

I was worried that carbon monoxide might be getting into my heaters,so I drove around with the heat on full,windows cranked closed. I had a Fluke Carbon Monoxide tester in the car with me and this thing reads in parts per million. It registered 000 for over 1/2 an hour,so my worries were for nothing- I still feel better having a window down slightly,just in case- Fred67bug

Sure - from what I understand, the only really different thing on a 75 non-super bug onward is that it has fuel injection. It is dual port but for the most part it looks the same as the carbed bug, from what limited things I've seen.

The heating system is still the same as the carbed bug ( not great :).

............"75 and later bugs have an entirely different exhaust system with better heater boxes which are much more effective in producing heat. You'll also notice that they have a different rear apron that has only one outlet for the muffler and which bulges out some to make room for the larger diameter muffler on the FI exhaust system.

........The engine cooling tin is a little different, The wiring harness is a lot different. They have 2 fuel lines and a gas tank that's also different than on the earlier carbureted models.

timmy

........As for the engine: The heads are different (smaller exhaust valves?). The alternator stand is different. And finally, I think that L-Jetronic engines have a slightly different camshaft grind.

Thanks for that -- yup, the car is different; I am sure most old parts won't fit the new so your point is well taken.

I didn't mean to minimize those differences but my thought was that the basic functionality of the heating system is the same. The parts might be different, maybe done better but it still works the same way.

also helping in the heat department is the thermostat that keeps the engine temps 10C higher...