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Randall C
Randall C, ASE Master Tech
Category: Chevy
Satisfied Customers: 12728
Experience:  ASE Master, L1, 32 years, Diagnostic / Electrical Specialist
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I'm on a road trip in my 2007 Suburban 1500 4x4. Noticed a

Customer Question

I'm on a road trip in my 2007 Suburban 1500 4x4. Noticed a little dripping from the air-conditioner I presume in the floorboard on the passenger side. A little while later the AC blower got real noisy and the airflow out of the vent decreased to almost nothing. Defrost and floor settings are fine without increased blower noise. Any suggestions?
Submitted: 2 months ago.
Category: Chevy
Expert:  Randall C replied 2 months ago.

Hello, you have a blocked AC drain, Its a small tube that exits the firewall down low to drain off condensation, Over time road debris, bugs etc block it. To fix?best you drop by a local shop, they put on lift, used compressed air and blow the debris out in like 5 minutes. DIY? you can but have to have compressed air, you can NOT poke anything in the tube or can damage evap core then big job. also, hard to describe location. Its down low on firewall, need to locate the rubber drain tune from underneath. Yes.. 100% the buildup of condensation in the HVAC case will affect airflow, cause noises and so on, generally does no further harm till you can get the drain blown out. In our shop? if a regular customer? we dont even charge for this. if you have to pay? it really only takes 10-15 minutes totoal and all shops know what to do

Customer: replied 2 months ago.
Is there a blow up diagram that can show me where to blow out?
Expert:  Randall C replied 2 months ago.

factory information does not show this, I have all that info , I had checked, Its on the firewall, down belwo where AC lines and heater hoses go into the firewall, so,, you have to get under and locate a small drain hose/nipple, very similar to these pictures. If the GM manual offered. I really would send so I have to try and describe. I am sorry, hard not being there, doing my best. here are the links to the pictures

Expert:  Randall C replied 2 months ago.

99% of the time, the drain hose is near directly down/below the AC lines where they enter the firewall indicating the location of the Evaporator behind the dash

Customer: replied 2 months ago.
To fix just blow compressed air into drain hose?
Expert:  Randall C replied 2 months ago.

yes, that is the correct way, A 911 way is one of those long tie straps, plastic ones. You can insert them fairly safely and not damage the evaporator core as they are soft. That is the only thing other than air you can put into the drain hose.

Customer: replied 2 months ago.
I stopped and inspected. Water was dropping out of evaporator when idling. Had a guy blast it with some air anyway just in case. After about 10 minutes with car running on idle and a lake under the car the blower was at full capacity. Two more hours on the road though it was back to same as before. Air not as cool. Stopped. Let idle. water seems to clear. Blower works. Air cold. Then cycle repeats. Thoughts?
Expert:  Randall C replied 2 months ago.

Sry for the delay, I am not following t he question,.Are you having ac problems or water running inside on t he floor, I was helping with the water on floor boards and ONLy way for that to happen is a blocked evap drain

Customer: replied 2 months ago.
The water dripping was the lesser of the two problems. Main problem was weak air flow. Both symptomatic of same problem?
Expert:  Randall C replied 2 months ago.

yes, possible and likely, When there is a backup of condensation in the HVAC case and not draining properly, it can affect the blower. It can rust bearings , affect the blower brushes and so on and will cause a diminished blower or airflow operation. You said originally water, then blower noisey then less airflow so, not being there and going on symptoms? the blower may have been compromised with excessive water in the HVAC case

Customer: replied 1 month ago.
Did the compressed air in the evaporator tube but do not think it was blocked due to the fact that water was dripping out. On the road again, air blows strong for 2-3 hours then diminishes. No water dripping in floor board that I can tell. Once I stop and sit idling for 10-20 minutes I see puddle of water under vehicle and airflow resumes. Is there anything else I can do?
Expert:  Randall C replied 1 month ago.

.if air speed is dropping on/off , goes back to possible blower damage from water now or in the past, the only way water on inside foor, clear water would have been evap drain, I still feel one prob caused the other, just hard not being there, I cab only send suggests, You may need a blower

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