in2pro

I was tidying up in the truck the other day and pulled up the passenger side floor mat and noticed the back side of the mat was damp and the carpet was wet....
First thought was water coming in somewhere from all the rain we have been getting...
First things first, I pulled up the carpet and jute padding and checked the body plugs for fitment, the floor pan plug was sealed up tight and not an issue.
Next up was the windshield cowling, I pinned the garden hose under the wiper blade and turned the water on, no water coming inside the people compartment.

Well that left the A/C drip line... I pulled the blower cover off and and noticed the tell tale sign of a water stain on the removal tab on the cabin filter



Telltale water stain on cabin filter removal tab

I pulled the filter and it was dry but you could tell it has been damp at some point, I installed the filter last April so it needed to be checked ( glad I did, it was filthy and ready for change!)




Filthy cabin filter after 14 months of use

There is no way to access the evaporator core drain area from inside without disassembly of the dash. I knew there had to be a drain for the AC but wasn't sure where.
A little guesstimating on location and sure enough I found it. It is located right under the accumulator, the line has a rubber elbow directing the condensate down, the rubber elbow can be removed put back on relatively easy as it is held on with friction only. HOWEVER you cannot easily access it from the top or bottom of the vehicle.
The easiest and best way to access it is to remove the wheel well liner, you are thinking that ah man that is a lot of work, but it is pretty easy and grants you tons of accessibility to that area!
You can reach the AC drain elbow, a bit blindly but easily, you have access to the dreaded #8 spark plug! and the O2 sensor to the right side cat! if you remove the tire you can really get in there (I did not have to remove the tire for the drain)






With elbow removed I pushed the vacuum cleaner hose all the way up against the firewall


Once I had the elbow off I used a 1.25 inch vacuum hose attached to my shop vac to suck out the drain, I butted the end all the way to firewall and let it vacuum for about a minute.

I used a handy-dandy endoscope from Amazon for ~$13 to inspect the evap core as best I could and to look inside the blower box... the endoscope was nifty but trying to push the equivalent of small rope around in there was difficult so viewing was limited, but still very cool! It plugs into your Android device for snapping pictures or taking video




endoscope that plugs into your Android device

I reinstalled the elbow and put the wheel well liner back and left all of the AC beauty shields off for several days to one, check that the leak was indeed fixed (it was) and two I left the jute and carpet dry out with towels stuffed in and around them.

I also discovered that the body floor pan right there is mere inches away from the catalytic converter and the steel floor pan gets hot!!!! hot enough that when you run your fingers over it you WILL jerk it away with expletives!
I used my laser temp gun and got a reading of 150F




Ouch! that floor pan gets hot from the catalyst

Anyway, 6 days later and she is still dry even after running the AC as cold as I could get it and stand it, to generate condensate.

I also installed a new carbon cabin filter



New carbon cabin filter (not cheap)

Typerod

Great write up! Did you check to see what the vacuum pulled out of there? What year did GM start using cabin filters in the Tahoe/Suburban? I don't think my pre-07 has one, I sure hope it doesn't b/c if it does have one, its been in there for 10 years, lol!

in2pro

Thanks Typerod!
Nah, I didn't look but suspect it was probably a buildup of algae and dust that made a plug, my shop vac was full of other stuff so unlikely I'd of seen anything. When I ran the borescope/ endoscope in afterwards, I did not see anything.
I added the cabin filter, the system comes ready for it.
It's a cut out and then install the filter and cap... here is that write up https://chevroletforum.com/forum/tah...r-25469/page3/
Having one (cabin filter) will keep the air and evaporator much cleaner, it will dampen the air flow a bit at lower blower speeds, but it will also requiring replacing every few year(s)
I believe having it will also increase the life of the evaporator because it will keep crud off the evaporator and causing it to corrode.

Typerod

Sweet! Thanks for the link to the cabin filter!

tech2

great diagnosis and write up.
talcum powder sprinkled over the floor pan is a nice aid in locating leaks...sprinkle then garden hose the exterior for 20 minutes....the water path can be traced where ever it flows over the talc.


Is a heatshield missing for the convertor?


They have been using cabin filters for a long time. to my surprize, my 2000 sierra has a cabin filter access door. It did not come with a filter from factory. I installed one.

in2pro

I don't believe so, but I will check, but it is likely that as hot as the cats get, that even the heat shields can only prevent so much transient heat from penetrating the floor pan in such close proximity.

Cliff Cook

I have a 1997 Tahoe and when my condensate line drains it pours and I am in texas but as soon as I notice it isn't draining ac not that cold why does it keep doing this help please