Smoke coming from Heater/Defrost Vents

[DiggetyDan]

Driving to work this morning I had smoke coming out of my heater/defrost vents. It wasn’t smokey like something burning, it was more of a moist mist. I had been away for a couple weeks (eloping) and I hadn’t noticed any smoke before, although there was a smell of radiator fluid while driving.

Couple questions:

1. Do you guys think it’d be OK to drive it home (it’s about a 5 mile drive)?
2. Any ideas of where I should start trouble shooting – I tried searching the forums but it looks like there have been some changes to the site.

Thanks in advance.

Dan

 

[66ALRIDE]

It sounds like your heater core is leaking. If you have a shop that is close by I'd have them pressure check it to see. If you do drive it home I'd check the radiator fluid level and make sure it's full, then leave the radiator cap loose so it doesn't build up pressure and you should be fine driving it home.

 

[bfoldy]

Agree. It's your heater core. You can pick up a new one pretty cheap and they're fairly easy to replace.

Should not be a problem with driving it...just roll your windows down and make sure you've got plenty of coolant.

 

[BwoncoHowie]

That happened to me. It was a pin hole in the heater core. You should be ok to drive it home. If you have to drive more than 5 miles, you might want to bypass the heater by looping the heater hose from the intake manifold back into the water pump (windsor motors). If you choose not to do the bypass and your bronco runs hot leave the cap tight or it might boil out. Coolant not under pressure has a lower boiling point. Keep an eye on your temp gauge when driving and you will be ok.

 

[TJK74]

Heater core for sure. Don't pressure test it. Just change it asap. Mine went out and by the time I noticed it I had a saturated passenger side carpet. Check your carpet if you have any for moisture. Mine was so soaked I ended up taking it out.

 

[SaddleUp]

As those mentioned above it's the heater core. If you only have 5 miles to drive it check the fluid level and then drive it home. Watch the temperature guage and it should be fine.

 

[DiggetyDan]

Well it looks like I've got a project for this weekend.

Thanks as always for the help guys.

Dan

 

[BG's 68 Bronco]

Just a warning for you... my cousin was driving with his wife down the main drag and his heater core blew up essentially. It filled the car up with coolant and smoke so quick he had to pull over immediately and jump out of the car. luckily his wife never got burnt by the coolant.

While this may not happen to you I just wanted to warn you. BTW it was a cavalier that did this, but that's not to say it couldn't happen on any other vehicle.

 

[Paco]

While you've got the heater box out, go ahead and do a rebuild on it and upgrade the blower motor. You will be glad you did.

http://classicbroncos.com/heaterbox.shtml

http://classicbroncos.com/forums/showthread.php?t=54371&highlight=chevy+blower+motor

 

[DiggetyDan]

One more question about the temperature cable

Well, I finally got the heater core replaced and the heater box cleaned and painted - thanks for the tech article "thesnake". And while I was at it I went and replaced the stock motor with the chevy replacement - thanks "hotwheels", great improvement in air flow. I even discovered that the heater blower knob actually pulls out to open the flow (it had been stuck before the rebuild).

When I was putting everything back together I chased the various cables to make sure everything was connected correctly. I chased the cable that runs from the far right "temperature" knob into the engine compartment and found out that it isn't connected to anything, it's just sitting there (and to think for the past year and a half I've been pulling it in and out thinking it was adjusting the temperature ).

Was hoping someone could help explain or post a picture as to where this should hook onto in the engine bay. I've got the heater core bypassed for the summer so it's no big rush but I'm darn curious as to where it could go. I've looked around and there doesn't seem to be any logical place for it to connect to.

 

[DonsBolt]

I chased the cable that runs from the far right "temperature" knob into the engine compartment and found out that it isn't connected to anything, it's just sitting there (and to think for the past year and a half I've been pulling it in and out thinking it was adjusting the temperature ).

Was hoping someone could help explain or post a picture as to where this should hook onto in the engine bay. I've got the heater core bypassed for the summer so it's no big rush but I'm darn curious as to where it could go. I've looked around and there doesn't seem to be any logical place for it to connect to.

Here is a pic of my engine, there is a valve that goes on the heater hose that comes out of the intake manifold. The cable you are talking about attaches to that valve.

If you are missing that valve most of the venders sell them

 

[TJK74]

Here is a thread that might help you with that valve and cable as well.

http://classicbroncos.com/forums/showthread.php?t=67226&highlight=heater+control+valve

 

[Paco]

Here's a few more pics for you....

 

[DiggetyDan]

Aha - very interesting

I never had one of those...which is funny because I'm thinking of all the times I've used that knob.

One more question - right now, since it's summer, I've got the hose that goes into the heater core connected straight to the hose that comes out of it (bypassing the core alltogether). Is there anything wrong with this set up? I don't have a pic since I'm at work.

 

[TJK74]

Nope there is nothing wrong with that except you wont have a heater;D
I ran mine like that for quite a while before I got around to rebuilding my heater box.

 

[DiggetyDan]

Allrighty then - looks like I'm good 'til the fall.

As always, thanks for the help guys - it's always appreciated.