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Fireman31

How To - Unclog Your A/C Evaporator Drain Tube

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If your truck isn't a Daily Driver and sits alot, you may encounter this problem. Recently, I had a flood in my SSS. Driver's Side and Passenger Side floor boards front to rear were soaked with water after a 5 hour road trip with the A/C on. No, it didn't rain at all. Upon checking the A/C Evaporator Drain Tube, I noticed it was dry. After sucking the water out of the rug with a shop vac, here is what you need to do to clear the clogged tube.....

 

 

TOOLS NEEDED -

pipe cleaners, found at any craft store or smoke shop

wet/dry vac

Febreze

 

 

Step 1 : Locate the drain tube(Passenger Side firewall under AC Accumulator).

HPIM1489.JPG

 

Step 2 : Remove the drain tube from the AC Evaporator outlet(Grab and twist/pull).

 

Step 3 : Use a pipe cleaner and clean out the drain tube.

HPIM1483.JPG

 

Step 4 : Use a pipe cleaner and clean out the AC Evaporator drain outlet, you may see the obstruction, but be careful not to knock it into the Evaporator.....You will get a nice gush of water as the Evaporator drains out. Please note that it may also drain back into the cab of your truck too, so have your shop vac ready.

HPIM1485-2.JPG

HPIM1484.JPG

 

Step 5 : Re-install the drain tube and run your truck's A/C to make sure the drain is working properly.

 

This is what came out if mine, it was right at the opening to the Evaporator.....

HPIM1488.JPG

....a spider's nest full of eggs! :freak:

 

NOTE -

Do not use compressed air, not only can you blow the obstruction into the Evaporator, if it is really stuck(like mine was), compressed air won't even do anything to remedy the clog.

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Forgot to mention, failing to correct this issue will result in a moldy smell in your truck, puddles on your floor, and worse yet.......a blown blower motor and resistor. :uhoh:

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good info danjamin!

 

there is an a/c coil cleaner that i'm sure is available at any major automotive store. that stuff works wonders. clean out the drain tube and just pinch them on occation to make sure they are clear. every-now-and-then, its also a good idea to run the fresh air for a while and not only recirculation, this will help cure that raunchy mold smell. with that much restriction around your evaporator, you were probably getting some ice build up.

 

on the freightliner M2 business class trucks, the a/c system will actually shut off if the filter is plugged up, but that doesn't always prevent the blower motor from overheating and burning the wires.

 

if you live in a humid envorinment and see the condensation from the evaporator dripping on the outside of the truck, then its pretty safe to say that your drain tube is clean, but if not...you may want to check them.

 

unfortunately, if you live a dry environment, like vegas, you won't always see water dripping, so it is a good habit to get in at every oil change just to squeeze the drain tube.

Edited by WODY™

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good info danjamin!

 

there is an a/c coil cleaner that i'm sure is available at any major automotive store. that stuff works wonders. clean out the drain tube and just pinch them on occation to make sure they are clear. every-now-and-then, its also a good idea to run the fresh air for a while and not only recirculation, this will help cure that raunchy mold smell. with that much restriction around your evaporator, you were probably getting some ice build up.

 

on the freightliner M2 business class trucks, the a/c system will actually shut off if the filter is plugged up, but that doesn't always prevent the blower motor from overheating and burning the wires.

 

if you live in a humid envorinment and see the condensation from the evaporator dripping on the outside of the truck, then its pretty safe to say that your drain tube is clean, but if not...you may want to check them.

 

unfortunately, if you live a dry environment, like vegas, you won't always see water dripping, so it is a good habit to get in at every oil change just to squeeze the drain tube.

 

evap-foam for the indoor and nubrite for the out door one..............

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Nice my tuck is doing this and i was wondering how to fix it thanks for the info.

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GLAD I FOUND THIS!!! I was having the same problem...

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First day on this site & you fixed my problem (I think)! My climate control blower went out. Took it to the Chevy dealer, they told me it was full of water. Referred me to a body shop to check for leaks. They wouldn't take my money, gave me a couple ideas of likely trouble spots. They didn't pan out. Checked with the mechanic at work, who mentioned this issue. Confirmed with a parts guy at another Chevy dealership.

So, using the above how-to, I pulled off the angled drain tube & a good pint of water came out! It was the tube that was plugged.

Now, wait to see if any other source of the water shows up, and replace my blower.

Thanks!

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Help me locate the passenger side firewall? I feel dumb, but do you jack up the truck and find it underneath or do you go to it thru passenger door under glove compartment? 

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Under the hood, passenger side, rear of engine compartment.  Look for the silver "bottle" (A/C accumulator) pictured in the original post.  The drain outlet is underneath.

Richard

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