The Stovebolt Site Forums The Shop Area General Truck Talk Two Questions - Cold Air and a Mystery Squeak

Hello Gents,

I have a 47 3100, mostly original ('51 216, radial tires, converted to 12V). The extended restoration notwithstanding, there was opportunity over the holidays to take a cruise of about 60 miles and two things were noticed:

1) The fresh air heater blows cold air, above outside temp, but largely cold air. When I replaced the core during restoration, there was nothing to prevent airflow around the core. Do others with fresh air heaters, particularly those that actually provide heat, have some gasket material between the core and housing to prevent cold air bypassing it? If not, any suggestions on what I might look for? I have confirmed that water is flowing through the core and both inlet and outlet hoses are hot. BTW, I'm still running a 165 stat, but the old heater worked with that same stat (the non-fresh air non-Chevy heater used before the restored fresh air unit was installed).

2) Towards the end of the run, I noticed a squeak at some stops. The squeak, or chirping, was not dependent on the clutch position so the throw-out bearing is not suspected. It's intermittent and I suspect the generator or the water pump. The issue is that I can't isolate them. Any suggestions beyond a mechanics stethoscope?

Thanks in advance for any insights.

Bill

It would be best to run a warmer 'stat, 180 or so, so the engine gets fully warmed up and burns off the water.

Ed

Another vote on a 180 deg. thermostat. Sorry no help on the chirp. Being a procrastinator at my core, if a problem doesn't smell too serious, I usually give to time to mature to the point it's easy to locate.

RonR

Bill, can't remember much as I tore my fresh air heater out some time ago but I do know I have a rectangular gasket laying on my work bench that I believe goes between the box/body. I'm not going to put my heater back n so if you want it let me know...... I can bring it to lunch next week at CFA.

Is it possible your "chirp" is just a loose fan belt?

Thanks all,

I've got a higher temp stat; I'll give a try. Its also easy to double check the fan belt, maybe the oil cups on the generator too.

Alvin, I'll pm you on CFA. looking forward to lunch.

Bill

Hi,
I found a patch of mineral wool between the heater core and the case on three sides of the core when I reworked my fresh air heater. It was worn and I left most of it out since the gap between core and case was quite small (about 1/8" or 3mm). I didn't have any ill effects so far.
Helmut

All,

Today I drained the cooling system and pulled the heater.

The gap between the case and the re-production heater core is at least 1/2 inch on one side and more than a 1/4 inch on the other, plenty of room to allow most of the incoming air to bypass the fins in the core. I filled the gaps with pieces of closed cell foam, cut to fit, and reinstalled the heater

While the system was dry, I put in a higher temp thermostat..

Success! The heater blows hot air now. My wife says she could dry her hair with it.

During the course of the afternoon, the fan belt was checked, and it was loose.

Maybe both issues are addressed now

Thanks for the suggestions.

Bill

Or do like I did. I drove two winters after rebuilding my heater with new everything, and my windows still fogged up and I still had to wear my carhartt's. I triple checked everything when I put it in, so I KNEW it was something in the system, but could not figure it out. This fall, I got desperate and swallowed my pride and checked the only thing I thought it could possibly be, even though I had checked and rechecked it before I mounted the works back up under the dash. I was so mad at myself I could spit when, after switching the hot and ground wires, that it had been sucking heat out of the truck and blowing it right out the vent that was supposed to be bringing air in to warm me up. Now I have to keep the window cracked even when it's on low, and that has been the case when it's been in the single digits! I can only use the high speed when I'm on the highway and it's below 15* outside. Two little wires and 5 minutes after freezing my butt off for 2 Missouri winters. So much for pride in one's work.

Hey, you fixed it. You could have went another Winter or two !