Hi all together.

This is my first post here, so first thanks and regards to all. - I used the forum before to get hints for the rear-gate-lock-blue-plastic-fitting-exchange

I am from Germany and drive a 2001 LT 4x4 here in the middle east. It's a fun to go offroad with the Blazer and explore the (for me) unknown nature here.

The problem is that my A/C puffs out smoke clouds in recycling mode that smells really bad but not like a burning cable. I am not sure but think that the smoke can only come from the A/C system itself, because it`s in recycling mode. The heater is never used, only the A/C is working everytime. What can it be? - And what is the difference between refrigerant smoke clouds (A/C) and antifreeze smoke clouds (heater core)?

Thanks for any suggestions.

Sincerely - Hirni

PS: The smoke comes out of the outlets in the center and on the sides of the instrument panel. I have noticed it on the drivers side.

 

You may have a blocked HVAC housing drain that is allowing moisture removed from the air to accumulate inside the housing. The fact that it only happens when in recirc may be due to the path the air takes in this mode.

The drain is almost directly above the frame where the HVAC housing meets the firewall on the passenger side.

 

Hope you can get it fixed. Nothing worse thatn your truck filling up with smoke when you turn the A/C on.



 

Thanks swartlkk,
hi carterx,
This was a good hint. I found the A/C gum housing on the engine side completely decomposed. Parts of it were melted on the exhaust near the lambda probe, but I could remove this scrap only just...
I think the smoke comes from engine coolant which is steaming out the overflow tank sometimes, when it's really hot (and here it is 47°C and more...).
Parts of the steam cloud may enter the HVAC because of the broken housing.
The steam/smoke comes through the vents only for some seconds, not continuous, and most times when I wait at a red signal in the city or when I left the highway...
May this be an explanation or not? What do you think? A new HVAC housing will make it or not?

Sincerely - Hirni

PS: Under the Blazer are no stains without the condensate that always drops down when parking. In the last 10.000 km I refilled 1L engine coolant. The upper manifold gasket and the thermostate is new and at the passengers side is no coolant on the floor. - Just tell me that I can sleep well and there is no need to be afraid of an engine breakdown on safari in the middle of nowhere.

 

This was no explanation...my heater core is broken. I ve seen the coolant coming into my car onto the floor under the ashtray.
For the moment I've removed the hoses from the heatercore and closed the connections at the engine with dead ends. - Is it ok to drive the blazer this way until the spare heater core arrives? Hope the engine cooling circuit is not blocked because of this emergency repair.

 

It should not matter, but you could always couple them together.

 

My heater core went in my old car, all we did was loop the hoses leading into the core back on themselves so that there is no coolant entering into the core.
This eliminates heat in your car (which is difficult in the winter, but I wouldn't see you having a problem now).
The other option would be to never turn the heat on, but I'm pretty sure coolant still flows through the core, just not as much...so you may still get a leak.

 

Coolant is always at full flow through the core.

 

Thank you swartlkk,
Hi Sisk28,

I am assuaged. And it's great to get your suggestions here at this nice forum. I feel like at home and it's really time to tune up my profile...

I've done without coupling the hoses because of the two different diameters.
Now I order the new heater core. Any experience which one is most durable: DELPHI part# HC0336, PROLIANCE part# 394195 or ACDELCO part# 1560087?

Sincerely - Hirni

 

I never cease to be amazed at what I learn from this forum! I would have never thought about the hvac housing drain. I normally don't post but just wanted to say THANKS! to all who contribute here.