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Is this normal?

19K views 11 replies 6 participants last post by  Manic Mechanic 
#1 ·
I havent towed for long distances with my 01 GMC since I've owned it,This past week I pulled my 33ft Sunnybrook TT to Ocean City,MD and about 3 hrs into the trip we noticed the A/c wasnt cooling the interior very good,which is wierd because you can usually hang meat in that truck it is so cold.Then my girlfriend noticed her side of the floor was hot. I know the cat convertors are under that side,and they get hot,esp pulling the 8500 lb TT + the golf cart and it was 88 degrees out.Is this normal or do I have a cat convertor starting to clog? The truck ran great,never went over 200 degrees,motor or trans,and I did notice that during stop and go it wasnt nearly as bad as running 70mph on the interstate.After leaving the interstate the floor cooled quite a bit,and the A/C was able to cool the truck again without needing #4 on the fan.
 
#2 ·
John, I think it's two different things. The floor getting hot when towing on the highway is probably normal. The A/C sounds like clogged up cabin air filters. The 01's have them and when the cabin air filters get stopped up condensation water seems to accumulate on the evaporator core. This happens to the extent that on long trips like your recent one the evap core water logs and can't cool well and you have to run the blower full speed to blow them it as much as possible. I've seen it happen on my truck and customers also.

Let me know if you are a do it yourselfer and I'll tell you the easiest way to replace them.

Vernon
 
#3 ·
Is the CAT stinking?
 
#4 ·
There may be too much Freon in the system. Mine will cool down a few degrees more if I traveling less than highway speed. I notice this after I took the truck in for warranty service for low freon level from the factory.
 
#5 ·
Vernon, Im a do it yourselfer with everything,I wrenched for a living for a long time,Dad owned a repair shop, I kinda was born into it,and still do on my own stuff.I'd appreciate instructions.I see filterone.com has the cabin filters (wix) .Its the only filter i havent changed on the truck--yet.

rcpd34,the cats do not stink at all,and there are no codes in the PCM,although i didnt look at the fuel maps at all.

SUMMITMAXLLY,the truck will otherwise freeze you out of the cab,until this particular trip.Even on a 98 degree day,you cant keep the fan on #3 or higher,unless your wearing a coat,its the best R134 system ive ever had.
 
#7 ·
mtchevrolet;1985255; said:
Mine will do this if its very humid outside. Its like it freezes up. I shut the AC off for a few miles and start it again. This happens when I pull my FW.I the the condensation freezes and must thaw out.
It was very humid out,and the water was pouring out the drain hole,about a quart in 10 minutes of idling at the rest area.
 
#8 ·
For those who need to change the cabin air filters 2000-2003 or 4? only. Obtain a 1/4" drive ratchet, small extension, 7mm and 5.5 mm sockets, small flashlight, and a vacuum with hose. Put some sort of temporary mat or bag on the passenger side floor to catch debris. Move the seat all the way back for under dash inspection and acess. The large black plastic dash under cover is secured by three 7mm screws along the front and hooks in the back. Only loosen the left most screw under the radio about 3-4 turns as it is nearly impossible to put back into place if removed. Remove the center and right screws and lay the sheild down still hanging on the left hand screw. On the now exposed HVAC box about half way between the door and center console you'll see a removable panel with 2- 5.5mm screws. It's about 2" wide and runs on the bottom from back to front then up the front about 4-5". Take the panel off and behind it are the filters. The first one is exposed and the 2nd is just above it. Wiggle them out taking note of their positions. Use a shop vac or similar to suck up all the dust and debris that will still be in the compartment and fall onto the sheild and floor. Install the new filters by sliding them into place making sure the foam applied to thier edges will seal against the walls of the box. Now just reinstall the covers.

With it done start the truck and kick on the A/C and be amazed at the difference. I'll never go more than 2 years between filters again.

Vernon
 
#10 ·
If it is freezing up, it could be low on freon. Check that as well. Also, did you have your foot in it hard to pull hills and such? The compressor will shut off under heavy load applications.
 
#11 ·
Duromax04;1988835; said:
If it is freezing up, it could be low on freon. Check that as well. Also, did you have your foot in it hard to pull hills and such? The compressor will shut off under heavy load applications.
I used tow/haul about 98% of the time,didnt need much throttle to hold 68mph,it rarley came out of OD locked up,only for good sized grades,the compressor was running,with the quiet 8100,you can easily hear it.The If its low on freon,it cant be that low,like i said ,it will freeze you out of the truck in day to day driving.
 
#12 ·
Just a note I since then determined that the cabin air filters were a 1999-2002 NBS only product. The GM catalog lists them for '03 but the evap case is different and there's no place for the filters to fit in.

Vernon
 
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