The air conditioner / heater system in my 2004 XC70 developed a moldy odor during the summer months. Now, after four months of heater-only winter driving, it still smells! Any suggestions on the proper clean-out of the residual mold? And, how to prevent a recurrence?

I have a 2005 v70. The problem just appeared this summer for us also. Went to the dealer and they sold us a "air conditioning" cleaning at our 32000km service. This involved checking the drains system and 'flooding' the system with a cleaner/deoderant through the vent system into the air cirulation vents which cost me almost $100 with tax. This Solved...or should I say masked the problem but it reappeared this month. Have been in touch with Volvo Canada twice and they say there is not record of any systemic problems with the air conditioning in this model but when I check the net...it is a problem...with many Volvo models. I checked for problems with other manufacturers aircon...but the bad mold smell seems to be more a Volvo problem. Many people report this mold buildup and foul smell in Volvo's. Volvo Canada suggested to take it back to the dealer and let them have a chance to 'solve' the problem. From what I have read and understand, it is the condensation buildup on the evaporator and system leaves moisture residue for spores to take hold. If the drains are plugged, the system becomes 'polluted' very quickly and unplugging helps for a short time. The major problem seems to the general moisture level. I take issue with the response from Volvo Canada because any form of mold inhilation is deemed to have health consequences. I only remains to see what will happen at the dealership when I take it in next time....but I don't expect much.

My on-line search came up with a few scary photos of plugged evaporators along the lines you describe. I was prepared to get a anti-fungal chemical to try to kill the spores, but to my pleasant surprise the problem did not reappeared this summer! The only remotely plausible explanation I've been able to come up with ----- the dealer checked / reset the blower control module to make sure that the blower would circulate air through the passenger compartment (and evaporator!) until the condensate moisture was removed. Actually, it does shut off as you leave the vehicle parked, but comes on automatically a while later after the temperature in the evaporator is back to ambient and most of the drainage has taken place. I don't recall how much time delay there is. Good luck with yours!

I have two 96 850's and they both have this problem. The lpt one has it worse and I got my local dealer to treat it with a "magic" fungal killing treatment that did not really help at all. The R is not as ad but as I am intending to keep it I am going to pull the dash to try and eliminate some rattles. At he same time I will delve into the evaporator etc to try to fix this nasty problem. I will report back buy don't hold your breath as it may take a while.

Mark

I had same problem. I replaced my cabin air filter and mildew smell is gone. Volvo has two air filters in car one for engine and one for inside car. I know that if you replace the cabin air filter the mildew smells will go away.

Though I'm new to Volvos, I've had this problem with other vehicles. After making sure drain holes are OPEN, I've had good luck in the summer by turning the heater on HIGH, temperature on MAX and simply closing up the car and letting it run for 15 or 20 minutes. The heat seems to help kill mold/fungus.

FWIW,

Steve

Heat will not kill mold and or fungus, you will only create and spread more. i am not trying to tell you what to do but trust me when i say this change your cabin air filter will be the best for you and your passengers

I have a 2007 S40 that has this oder problem with the AC, it has had it for months and will not go away. Any suggestions for remedy?

my local oil change place has a service in which they spary the evaporator to clean out the mold. i personally haven't had this experince. yet, but am still waiting. anyway, i know several people who have had this done to their cars and are pleasantly surprised by how well it works. just a thought for you next time you pass a jiffy lube, or something similar. good luck and keep us posted.

I had a problem like this. We first noticed it when it seemed that the ac was not working. Subsequently, it developed a mildew odor. The dealer sprayed some stuff over the evaporator which in itself had an obnoxious odor and did not do much, if anything, to eliminate the problem or mask it. The drains did not appear to be clogged--they did not report them as such. The evaporator and a sensor were replaced under warranty AND the heater/ac blower fan set (via software change) to come on for 5 or 10 minutes about an hour (or whatever) after the car has been turned off. The problem has not recurred since.