Smoke coming through vents


travis2822
12-07-2007, 10:26 AM
99 Blazer 4x4 4.3l

Driving home yesterday and smoke started coming through all of my vents, condensation and water drops were on the windshield. It smelled like antifreeze.

I am assuming that the heater core is bad. I flushed the system about 2 months ago and all was fine until yesterday. I have the standard climate controls, nothing automatic.

Is there a possibility that this could be something other than the core? Just wondering before I start taking the dash apart this afternoon.

Thank you,

DVDr
12-07-2007, 11:09 AM
Exactly the same thing happened to me, this past weekend,

I picked up the car , drove home for an hour dorwning in antifreeze ( that sweet smell ). In my case it was only comming from under passenger side due to turning off blower motor.

dropped it off to the mechanic a few days ago, and he said it was exactly that.

I have automatic climate control, but I guess thats not related.

Taking apart dash is the key I guess.

Do you have the schematics by anychance ? or your going to wing it ?

MT-2500
12-07-2007, 12:16 PM
99 Blazer 4x4 4.3l

Driving home yesterday and smoke started coming through all of my vents, condensation and water drops were on the windshield. It smelled like antifreeze.

I am assuming that the heater core is bad. I flushed the system about 2 months ago and all was fine until yesterday. I have the standard climate controls, nothing automatic.

Is there a possibility that this could be something other than the core? Just wondering before I start taking the dash apart this afternoon.

Thank you,

It is usually the heater core.
Check around the bottom heater housing for coolant leak.
Sometimes a rad pressure test will show where it is leaking.
Make sure where the heater hose goes on to the heater core is not leaking and blowing back into heater housing.

IF THE OLD GREEN COOLANT do not breath in the fumes.
They can cause health problems.

If heater core is leaking the hole dash has to come off to get to heater housing and heater core.
8-12 hrs labor.
Good Luck
MT

MT-2500
12-07-2007, 12:22 PM
Exactly the same thing happened to me, this past weekend,

I picked up the car , drove home for an hour dorwning in antifreeze ( that sweet smell ). In my case it was only comming from under passenger side due to turning off blower motor.

dropped it off to the mechanic a few days ago, and he said it was exactly that.

I have automatic climate control, but I guess thats not related.

Taking apart dash is the key I guess.

Do you have the schematics by anychance ? or your going to wing it ?

Check around in the how to section.
There may be some heater core replacement section.

A factory repair manual or the All data sub is your best bet for information on heater core replacement also parts and labor guide in all data to.
Along with all of the AC/heater auto matic control information.
24.95 $ US plastic and you are set to go in 10 minutes.
One year online repair information SUB.
Will pay for itself with one repair.
MT
http://www.alldata.com/products/diy/index.html

travis2822
12-07-2007, 04:35 PM
I am currently working on it. I have the dash all apart and everything ready except for the one screw inside the EVAP. I cannot find it anywhere searching with my hand. any advice?????

MT-2500
12-07-2007, 05:02 PM
I am currently working on it. I have the dash all apart and everything ready except for the one screw inside the EVAP. I cannot find it anywhere searching with my hand. any advice?????

There will be 1 or 2 on under side the ac housing.
That will have to come out from engine side of firwall

But the bearcat one I found on a 01 is inside the ac core housing.
Not sure a 99 has it but.
Remove resistor block or heater blower module and look about half way down in there.
For a screw head it may be no 10 metrick and you will need a good wobble socket to unscrew.
Good luck
PS
Most of The dash wiring can be left in the dash and just unpluged on both ends of dash.
MT

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