Evaporator stink, how to get rid of it?

[jyount]

Every since we have had our 2007 the a/c (haven't used the heat) stinks. When you first turn it on it is like you are burning trash in the front floorboard. I know it's bacteria/fungi etc, but can I clean it w/o taking the dash apart? Cut bleach etc? Can I get to the evap through the cabin filter hole? If I need to drill the case I am not to proud to duck tape it back up at this point, just where can I get to it.

[auto trainy]

I have a 2000 Mercury GM and since new it always had your problem and the reason was because of the evaporator fins are horizontal they always retain moisture (design),I haven't heard of this with a GM car but after the third visit to the dealership for deodorizing they installed an after blower kit which consisted of a sensor that measures moisture within the blowerbox and allows the blower to run on high until the moisture is gone,this greatly improved the condition but not all together,there is one thing that you will notice is that its hot wired (constant voltage) which means that if moisture is detected the blower will start on its own even if the car is off.I don't know if it is available for a GM but it doesn't hurt to ask. hope this will help GOOD LUCK.
Note:before doing anything drastic make sure the drain is clear and open.

[Tech II]

GM had after blow modules, that would cause the blower motor to run for a certain amount of time after the engine shut off, if the A/C had run during a drive cycle....in some cases, the module was added...in some cases, it was programmed into the system, depending on the year....

[jyount]

Originally Posted by auto trainy

I have a 2000 Mercury GM and since new it always had your problem and the reason was because of the evaporator fins are horizontal they always retain moisture (design),I haven't heard of this with a GM car but after the third visit to the dealership for deodorizing they installed an after blower kit which consisted of a sensor that measures moisture within the blowerbox and allows the blower to run on high until the moisture is gone,this greatly improved the condition but not all together,there is one thing that you will notice is that its hot wired (constant voltage) which means that if moisture is detected the blower will start on its own even if the car is off.I don't know if it is available for a GM but it doesn't hurt to ask. hope this will help GOOD LUCK.
Note:before doing anything drastic make sure the drain is clear and open.

The drain is. When I worked at the dealer we had I believe a 2003 Impala that had the stinks. Come to think of it we talked about an after blow kit for it, but never did it, she parked with the front uphill. We ended up pulling the dash and replacing the evaporator, then telling her to park with the rear uphill to put the drain lower.

Originally Posted by Tech II

GM had after blow modules, that would cause the blower motor to run for a certain amount of time after the engine shut off, if the A/C had run during a drive cycle....in some cases, the module was added...in some cases, it was programmed into the system, depending on the year....

Mine doesn't have it, but I honestly hadn't thought of adding it...

[Tech II]

Can also try a can of Lysol on the fins of the evap.....

Maybe someone can check for a TSB on this "smell" for you.....

[jyount]

Originally Posted by Tech II

Can also try a can of Lysol on the fins of the evap.....

Maybe someone can check for a TSB on this "smell" for you.....

Thought of that too, don't know how strong that smell will be. If I need to I can go to the dealer where I worked and lookup TSBs.... Thinking a spray a day for a few days is what it may take to effectively kill the bacteria etc in it...

[Tech II]

Here's one thing I do with the wife's car......she doesn't like A/C, rather drive with the windows open.......but when I drive, I want the A/C on.....

Had a real humid day, A/C worked great........couple days later on initial start up of A/C, you could detect a slight smell......

So I became my own blower control module......when I got home, shut A/C off, then turn heater on to full hot, in recirc mode, and let it run for 5 minutes......that hot air dried out those evap fins, and next A/C start up, no funky smell.....now in your case, I would use that Lysol first.....

[j cAT]

Originally Posted by jyount

Every since we have had our 2007 the a/c (haven't used the heat) stinks. When you first turn it on it is like you are burning trash in the front floorboard. I know it's bacteria/fungi etc, but can I clean it w/o taking the dash apart? Cut bleach etc? Can I get to the evap through the cabin filter hole? If I need to drill the case I am not to proud to duck tape it back up at this point, just where can I get to it.

this smell condition is because when they switched to R134 refrigerant the coils of the evaporator need be closer together. so then the smell started. GM has a smell/odor removal procedure and some chemicals with special instructions on this operation. the interior of the vehicle need be covered to protect from damage.

then GM found that if you placed filters in the air box odors where greatly reduced. this is because with clean fins nothing can grow on the evaporator. also the drain works perfectly.

I understand now that GM took out these filters for some reason .

any way I have a 1996 and I installed my own filters before the blower to keep the air box clean. my 2000 Silverado has a GM air filter in it as built. both vehicles have no smell.

keeping the box dry will help reduce odor. as mentioned operating for a few min in max heat rec mode should reduce the water / odor. but with a lot of organic goop it may not dry out the air box properly

[gmtech1]

Originally Posted by Tech II

Can also try a can of Lysol on the fins of the evap.....

Maybe someone can check for a TSB on this "smell" for you.....

TSB PIC3744E addresses the A/C odor and has the tech enable the afterblow system using a Tech2 scanner.

[jyount]

I lysoled it. Seems to have got the stink for now, will do it again though. Now the recirc/outside motor click click click when its to the outside. I have looked as much as possible and can't see an obstruction. The motor works fine, just when it gets to the end of the outside air position it acts like its stuck, but it isn't. What is the deal? It acts like it doesn't know where it is, ie gets to closed and tries to keep going...

[rkvons]

Originally Posted by jyount

I lysoled it. Seems to have got the stink for now, will do it again though. Now the recirc/outside motor click click click when its to the outside. I have looked as much as possible and can't see an obstruction. The motor works fine, just when it gets to the end of the outside air position it acts like its stuck, but it isn't. What is the deal? It acts like it doesn't know where it is, ie gets to closed and tries to keep going...

If that little motor module that controls the door to recirc and outside is clicking, it has a stripped gear in it. I think the computer is commanding it to go all the way until it stops, but because it is stripped, it does not stop. It has plastic gears in it.

[jyount]

Originally Posted by rkvons

If that little motor module that controls the door to recirc and outside is clicking, it has a stripped gear in it. I think the computer is commanding it to go all the way until it stops, but because it is stripped, it does not stop. It has plastic gears in it.

Thanks, been working and haven't messed with it, figured as much. The best thing is its about 30 bucks and easy to get too. Just put the driver's side door motor on our Suburban. Close to 200 bucks and pulled both front seats, center console, then the dash to get to it....

[jimbob0077]

I could write a book about that topic. GM made a design mistake on the evaporator and instead of fixing the problem they attempt to cover it up with the after blow module. I have a 2003 Impala. The dealer hardwired an aftermarket module in the blower circuit that lasted one year. Then they told me to get lost. GM has a liquid spray treatment that I shoot into the open recirculation door area when it really stinks. (P/N 12378554 GM Odor Eliminator). Listen to Tech I. TSB PIC3744E. All they have to do is turn the module feature on. Had a 2010 Silverado with that module and it cured about 90% of the problem. To bad more people don’t complain. Then maybe GM would fix it instead of jury rigging it.