Finally got around to getting my 1990 beater on the road. Put a new windshield,tags,insurance today. Drove great to and from work then.....I stopped at a local lube then left to go home. Did not get 20ft from there when smoke pored out of my AC vents and filled the cab in 10 sec. Pulled over,I thought it was on fire but found nothing. My heat was on low so i started back home ( i was 1/4 mile from home) when it started again. It smells like a barn fire smoke and so do i now. I shut it off again to check and again nothing. I turned the heat off and hauled a$$ down my road and got home. Dont do it when the vents are off. Im thinking heater core but ive never seen one smoke that much. What do yall think?

 

More likely the blower or the fan resistor. There is a resistor for the fan motor that oculd do that.

Try putting the fan on full out high. If it starts to do it in that situation, it's probably the fan motor. When you have the fan on high, the resistor is bypassed.

 

it could be a rats nest or something that was sitting on the intake or something.

 

I just went out and ran it for 5min,not doing it now.....wtf. When it was doing it heat was on low and it was set on defrost. The cab and I smell like burning tree limbs and leafs. John, I tried doing what you said but its not smoking now.

The smoke was coming out of my panel vents when it was on defrost.

 

You said you got your oil changed? They could have dumped a bunch of oil on your manifolds and it burnt off.

edit: but idk how that would get in the vents.

 

That could be it actually. It could bleed through the back edge of the hood and get sucked right in the vents.

I like the "Rat's Nest" theory also, lol. Maybe it was an oil soaked rat's nest laying up against your fan resistor, lol...(combine the theories...)

 

I did not get my oil changed i went up there to see if they do state inspections.

I know what burning oil smells like and that smoke smelled like a brush fire.

 

If the heater core did blow then wouldn't it smell like anti freeze and had a residue on the vents?

 

yeah, the smoke would smell very sweet and you would have a puddle on the floor of the truck.

 

Well check anti freeze fluid its full,cranked it up and looked around,not doing it anymore but now the no air will come out unless the fan is on full out high. Will not work on any other speeds.

 

I think it was.....the Flux Capacitor!! This is commonly caused by a phase shift in the matter anti-matter injectors.

Sounds like something made its home in your truck while it was parked...

 

I think Rev's on to something. Look for a neutrino flux next time it happens -- that would be a strong indicator.

That or the smell of leptons (muons don't have an odor...)

 

ha ha ha....ok serious answers now.

 

I think John hit it on the nail....fan resistor.

 

Yep, sounds like it. Nevermind sniffing for leptons then...

 

Yep. The smoke was from your fan speed resistor pack burning up. The reason your fan only works on high now is because there is nothing left to burn.

 

Will it be safe to drive? I think not turning the heat on will be a good idea. Auto Zone said the 87 rangers were the last years to have flux capacitor installed behind the dash.

 

You can use it. Just use the fan full on, or full off.

 

Hey, Matt. Long time no talk to.

 

Thank yall,doubt ill fix it anytime soon. I was fixin to blow it up cause i just put 300 bucks in it getting it legal. Still have to buy tires too.

 

The partical sun is returned! Good to see your back John!

Yea, you should be fine to drive. However to be on the safe side, do not set the fan for anything but high or off.

 

10-4....thanks for everything

 

Ha ha! And judging from my posts here, sub-atomic particle sun...

 

does anyone know what could of caused it?

 

They just go bad after awhile, Kevin. They run hot as they slow the fan down by getting rid of some of the electrical power as heat. They are mounted in the intake airstream of the fan to keep them cool -- but basically they are a heating element and like any heating element they eventually burn through.

I don't think they're very expensive, and it's like 2 screws to get it out and replace it and a connector that plugs into it. Should be easy.