# Gen 2 Heater Box Drain?



## Iamantman (Sep 24, 2018)

Hey everyone,

Just curious if anyone knows of a functional drain anywhere on the 2nd gen cruze for the heater box inside the car? I had some cooling system issues last year and coolant collected and forgot about it till this morning when I nearly got smoked out of the car on the way to work ha. Pulled over, verified I didn't have any coolant leaking anywhere and opened the windows and all was well within 10 min or so of driving nad opening and closing all the vent positions. Would love to just be able to inspect that under the dash though if possible. 

Hell, I'll even drill a small hole in the housing just to keep it from happening again (original repair was a new coolant fill tank which was cracked and leaking vapors in through the cowl.)

Thanks!


----------



## jblackburn (Apr 14, 2012)

Typically only the evaporator box has a drain. The heater core is usually separate in most designs, with a flap that directs air one way or the other.

Does it still smell like coolant when you run it on the cool side with A/C off, or only when you turn on the heat?


----------



## Iamantman (Sep 24, 2018)

jblackburn said:


> Typically only the evaporator box has a drain. The heater core is usually separate in most designs, with a flap that directs air one way or the other.
> 
> Does it still smell like coolant when you run it on the cool side with A/C off, or only when you turn on the heat?


Ah understood. When you say run it on the cool side, what exactly do you mean there?


----------



## jblackburn (Apr 14, 2012)

Iamantman said:


> Ah understood. When you say run it on the cool side, what exactly do you mean there?


Temp knob on cool, AC button off.


----------



## Iamantman (Sep 24, 2018)

jblackburn said:


> Temp knob on cool, AC button off.


Gotcha thanks. I'll test it at lunch and see. 

Is that effectively blocking coolant flow to the heater core to check for a leak? I didn't think coolant flowed through unless I had the fan turned on as well.


----------



## jblackburn (Apr 14, 2012)

Iamantman said:


> Gotcha thanks. I'll test it at lunch and see.
> 
> Is that effectively blocking coolant flow to the heater core to check for a leak? I didn't think coolant flowed through unless I had the fan turned on as well.


Coolant's always flowing through the heater core. Heater core control valves haven't really been used since the 80s - they were prone to leaking. The HVAC temp control flap(s) just decide what side (hot/cold) to push the air through.


----------



## Iamantman (Sep 24, 2018)

jblackburn said:


> Coolant's always flowing through the heater core. Heater core control valves haven't really been used since the 80s - they were prone to leaking. The HVAC temp control flap(s) just decide what side (hot/cold) to push the air through.


OK makes sense. Last time I was in that area was when I installed my boost gauge and routed my wiring through the console and all was dry then. Better double check that as well. 

So what are you trying to diagnose with AC off on cool?


----------



## jblackburn (Apr 14, 2012)

Iamantman said:


> OK makes sense. Last time I was in that area was when I installed my boost gauge and routed my wiring through the console and all was dry then. Better double check that as well.
> 
> So what are you trying to diagnose with AC off on cool?


It should tell you if the smell coming from the heater core area vs whole HVAC air intake. I haven't heard of a leaky heater core YET on a Gen 2, but it definitely happens in GM products.


----------



## Iamantman (Sep 24, 2018)

jblackburn said:


> It should tell you if the smell coming from the heater core area vs whole HVAC air intake. I haven't heard of a leaky heater core YET on a Gen 2, but it definitely happens in GM products.


Ok so ran it up to temp a little while ago and started with the temp in full cold, fan and AC off. Then switched over to full hot for a couple min. Then turned on the fan in and switched back and forth as well. Then for good measure also tested both temps with AC on and AC eco mode on. 

I was not the disaster from this morning that's for sure (smoke and smell) but I did smell sweetness when I turned the fan on. And could be crazy here but it seemed like the odar was stronger when not on full cold or full hot, but in between temps. 

The other thing that I didn't mention because I'm not entirely sure it was my car because I was on the highway but I smelled what smelled like an electrical burning (think ac clutches) just before I noticed the smoke coming from my cabin. I cracked the windows and then pulled over to inspect and all seemed fine so I continued on and the smoke and smell both went away after a little bit of driving.


----------



## snowwy66 (Nov 5, 2017)

While I haven't had the problem with my cars. Most of the semis I drive accumulate moisture from the ac. And when switched to heat. The windshield fogs up.

This time of year with mild temps and sometimes rain. it's pretty common to switch from ac to heat and ac.


----------



## Iamantman (Sep 24, 2018)

snowwy66 said:


> While I haven't had the problem with my cars. Most of the semis I drive accumulate moisture from the ac. And when switched to heat. The windshield fogs up.
> 
> This time of year with mild temps and sometimes rain. it's pretty common to switch from ac to heat and ac.


Thanks. Yeah wasn't an issue today so I think it was more of a seasonal type thing like that. Just kinda scary in the moment for that much smoke to billow but I didn't have that issue today at all so I think all is well. I checked codes too and all clear. 

Just being paranoid I guess


----------

