A/C Drain

[Read]

85 C10 1/2 ton is leaking water into passenger side carpet. I am assuming it is a drain plug issue. I need help first locating drain and then fixing the problem. Any help would be much appreciated.
Thanks!

 

[yevgenievich]

Bottom of evap box under the hood.

 

[Read]

Thanks. Do I have to remove the box or can I access plug without removal?

 

[yevgenievich]

Just reach to the bottom of HVAC box under the hood and feel for an opening. Right below the AC lines and back towards the firewall a bit

 

[Read]

Found the hole and it doesn't appear clogged or even wet for that matter. Very wet on inside firewall underneath insid evap box. Any suggestions?

 

[yevgenievich]

Could be leaking from the cowl or the vent. There is a drain behind bottonrear fender area for the cowl. Or heater core

 

[Read]

Thanks. I am very much a novice as this is my first truck and I am trying to learn/figure out as I go. Reason for all the questions.
So are you saying possible heather core is leaking/bad. Would that mean that there would be a constant leak even when a/c running? If only leaking when a/c running then a drain issue?

 

[Read]

Just went for a drive w/o a/c running and still leaked once back home. Looks to be coolant instead of water. Was thinking a bad heater core but heat works and blows warm air. Any thoughts?

 

[yevgenievich]

If only when AC running, then likely is drain issue from the evap core. If constant then all other possibilities. The cover can be removed to verify but is a pain. Some access can be had through inside without total disassembly

 

[yevgenievich]

Just went for a drive w/o a/c running and still leaked once back home. Looks to be coolant instead of water. Was thinking a bad heater core but heat works and blows warm air. Any thoughts?

Heater core leaking. The inside HVAC box has to come out. There is a sticky around HVAC area of the boards

 

[yevgenievich]

Can bypass heater core to verify for sure

 

[Read]

Would heater still be working if core bad?

Are you saying that if I bypass core and it doesn't leak then I know it's a bad core? How do i bypass? And is it fine to keep the bypass and drive like that?

Was able to gain some access from front as you said but not able to see much or know what to look for. All along the bottom of inside Hvac box it is wet along the carpet. Seems like too much for evap drainage since I only drove a few miles.

Thanks again for your help?

 

[yevgenievich]

Heat still works, just leaks while working. Bypassing is fine as long as hoses are not capped off. Heater line still needs to make a loop. There are some configurations where capping is ok, but safer to loop the hoses skipping the heater core.
Heater core replacement takes some time, so it often gets bypassed in these trucks.

 

[KilgoreTrout]

Yes, the heater would still work.
Hot coolant flows through the heater core (basically a radiator thats inside the dash). Air flows past the hot coolant in the heater core, and gives you heat in the cab.
You can bypass it by hooking the coolant lines together at the firewall. Two coolant lines. One goes in to the core, one comes out. No flow will go through the heater core, therefore it shouldn't leak afterwards and you'll know it's the heater core.
And yeah, you can drive it like that but your heat won't work because you bypassed the heater core.

 

[KilgoreTrout]

Heat still works, just leaks while working. Bypassing is fine as long as hoses are not capped off. Heater line still needs to make a loop. There are some configurations where capping is ok, but safer to loop the hoses skipping the heater core.
Heater core replacement takes some time, so it often gets bypassed in these trucks.

I pray every night to the Chevy gods that they don't make me do mine.
Seems they've decided to give me everything else to do instead.