A/C heat bad odor
 

My heat and A/C system has just started emiting a bad odor from the vents when in use. This odor is very familiar to me, as I once had a Jeep that blew rancid air, and the cause was a dirty evaporator. My questions is, how difficult is it to access the evaporator on a 1999 E300TD? Thanks

Is the water draining out from under the car when you use the A/C? If not then you likely have blocked evaporator drains. You can buy commercial A/C system disinfectant that will kill the bacteria growing inside. I'm not sure if you can remove the cowl and blower on the W210 and clean the evaporator from the front. Otherwise it is a lot of time to remove the dashboard and interior from inside.

My ac drain line must be clogged up because its not dripping any water. Does anyone know where the drain line is located and the best way to unclog it on the W210?

Usually they are in the middle of the car by the transmission tunnel. You can jack the car up and look for the hoses in that spot and put some flexible wire up to see if there is debris blocking them.

W210 Evaporator Drains
 

I've never unclogged these drain lines, and I actually have never looked at where they come out underneath the car, but I did replace them when I replaced the evaporator on my W210.

There is one on each side of the center console. IIRC, if you remove those PITA panels underneath both sides of the instrument panel you should be able to peel back the carpet at the center console and reveal the pipes (flexible, insulated, spongy thingies about 6 inches long). They are clamped to the bottom of the box that holds the evaporator and heater core.

If you try to snake these out from underneath the vehicle make sure that you are not poking too far into that air handler box - you don't want to hit the evaporator.

Psssst - under the hood It is just a little right of center at the back of the engine compartment