I'd thought I had a vacuum motor problem causing the low volume of air issuing from the panel vents & defroster. After finding the various ducts all working correctly, I suspected a mouse or bird's nest might be blocking the air flow. What I found was 225,000 miles worth of crud plastered onto the AC evaporator, effectively blocking air passage through it! Note that all incoming air must pass through the evaporator. Attempts to brush off the crud, blow it off with compressed air & vacuum it off w/the Hoover did little to improve the situation. The biggest improvement came from picking debris out w/my fingers. Digging through Chilton/Haynes gave few ideas. There was mention of aerosol AC coil cleaners sold at auto parts stores, primarily to deal with bad odors. Calling around I could not find any. Considering spraying what I can see down with household cleaner then using garden hose, but figure it'll be a mess & just force crud deeper into the evaporator. Not sure where water sprayed into evaporator would end up, only drain seems to be inside under the heater coil. Presumed there's also an AC condensate drain, but all I see so far is the peculiarly placed tube going to the blower's brush/commutator.

Short of discharging the system & removing the evaporator for serious cleaning what good options can members suggest to deal with this issue? There doesn't look like there's much room to be gained by removing the front/top section to the evaporator housing or enough flexible hose to lift the evaporator w/o discharging. Help, summer's almost here!

 

There is a foaming coil cleaner you can get at the hardware store or a home A/C or appliance repair shop, meant for the outside condenser but works for evap too (the home A/C guys may call this the "A-coil"). Stuff did work nicely on my home AC. You'll need to wash it off though, which is kinda hard to do. The condensate drain will work as long as the water flow rate is not too high.

It may have a chemical smell for awhile.

While you're at it, use the rest of the can to clean off your home's A/C condenser. There's usually enough dirt on it to make a difference in the bills.

 

I just did this last night while replacing my radiator. While the procedure will obviously be different in your van as opposed to my Ranger, it was pretty easy for my to clean mine up.

The condensor in the Ranger lies in front of the radiator. While spraying the front of the condensor with water doesn't do a lot, spraying it from the rear with the radiator off helped a ton and blew a lot of dislodged crap out of it.

Just my two cents.

 

Thanks, was thinking home AC shops would have something suitable.

Still surprised the auto parts stores were stumped after reading about it in Haynes. Might have just gotten the wrong parts guys.

 

That's odd, it's sold everywhere.

The brand name is: OZIUM and it's sold at auto parts stores nationwide and at car wash places. The car wash outfits also sell other brands of deodorizers.

 

I'm talking evaporator here NOT "condensor". Every vehicle condenser I've ever seen is in front of the radiator. Condensers are extremely easy to clean compared to evaporators. Makes little difference if its a van or PU.

The evaporator fits closely inside a closed box on the firewall between the heat/AC fan & the plenum to the heater core or interior. Access is limited to the hole exposed by removing the blower, unless you want to tear down the entire housing and/or remove the Freon & make a major deal out of it.

Evaporators do all the dehumidifying, & paradoxically, cause the moisture to condense on their surfaces. It is this wet in operation condition that results in dirt & mold accumulating on the core, ultimately blocking it.

Conversely, vehicle condenser surfaces run hot & dry, the condensing is all done on the inside & refers to the Freon condensing.

Home ACs are different, having filters to reduce the accumulation of dust on evaporators. Typically blowers throw the water coming off the evaporator onto condensers, which cools them & speeds their function. It also causes mold & dirt to accumulate.

 

Spraying OZIUM on an a/c condenser wouldn't benefit anything, but it might attract a few bees.

The evaporator core fits into the plenum chamber, which has a built in drain to get the water out caused by the condensation. The drain hoses tend to kink, rot out, or get plugged up.

 

So you do not recommend any of the aerosol AC cleaners?

I called 3 major chain auto parts stores & struck out yesterday, let alone stock it, none had even heard of such a product. This is in FL where AC is vital. As I posted I might have just gotten the wrong employees. Might expand my search today. Or just go at it with household stuff & garden hose, after locating the AC drain & making sure its clear.

 

Nope! Struck out on aerosol AC cleaner in Gainesville. Did pick up on the suggestion of using either the citrus or purple degreasers. Household citrus cleaner or detergent did nothing to dissolve the uniquely gummy road dirt that had been plastered on the evaporator for 15 years & 226K.

Trying to blast the crud away using the garden hose thru the blower opening was also pretty pathetic, but I threw the blower back in place & it did restore some of the lost volume. Determined to do better I resolved to open up the evaporator housing & see if I could wrestle the it out enough to clean. Had to remove the accumulator to free up the lines, but found it was just possible to get the evaporator tilted/twisted up out of the box & prop it up on the radiator support. Once exposed the full extend of the blockage was evident. I spent over an hour picking the heaviest crap out of every tiny fin on the unit, then covered the paint work w/plastic & aggressively brushed Purple degreaser (reduced 4 to 1) into each fin w/toothbrush. Let it sit for awhile rinsed w/blast from hose, drained & repeated. I can actually see light thru the core now! Left it to dry overnight, assured that most of my airflow will soon be restored.

 

Home A/C units work the same as a cars A/C system, the condenser is outside the evaporator is inside. If the air is being blown over the evap coil then the condenser, it is a dehumidifier. The evaporator boils off(absorbs heat) the liquid refrigerant from the condenser produces(expels heat).

To find the spray on coils cleaner, look for refrigeration supply house(distributor) they are probably not listed in the normal yellow pages. Also look for "no-rinse" type.


http://ftp.nucalgon.com/ftp/prodlit/3-38F.pdf
http://www.nucalgon.com/nucalgon/web...saler?OpenForm

 

I've used OZIUM for years, and can buy it at two local car washes, and at the local Kragen's (Checker) auto parts store. Dealers were the first to use OZIUM, it's been around since at least the 1960's.

Type OZIUM into your search engine, there are myriad companies that sell it. Prolly someone close by to you.

 

Home AC, specifically window units are DIFFERENT in the ways I pointed out. To my knowledge there is no such thing as an AC that was not a dehumidifier.

Home AC units have washable/replaceable filters that reduce the accumulation of effiency robbing dirt on evaporators. Vehicle AC DOES NOT have such filters, except in rare instances.

Home AC has the blower behind the evaporator pulling air thru & picks up the condensate blowing it directly onto/thru the condensor, increasing its efficiency. Vehicle AC, in this case FORD Econoline, has the blower in front of the evaporator pushing air thru directly to the interior, condensate drains to the ground. The condensor is located remotely ahead of the radiator & does not benefit from being wetted by the condensate. A 2nd fan assists in cooling the condensor, although at speed air pressure is sufficient.

These are major differences between how home & vehicle AC works.

 

Not sure if you were pointing out 'condensor' rather than evaporator. Either way it was not much of a recommendation.

Besides, its too late. I asked around for Ozium & did not find anyone familiar w/it. The suggestion to use Purple degreaser was very appealing b/c I had a gallon of it & had not considered it. Diluted 4:1 the Purple degreaser worked extremely well to clean the evaporator. I looked thru the fins w/light & its 99% spotless.

 

Yes, all A/C systems are dehumidifiers. If you blow the air over the evaporator then the condenser, then it is strictly a dehumidifier.
Window and split A/C systems have two separate blowers one for the evaporator, one for the condenser(window units have a double ended shaft motor). Home split systems do not blow condensate water on the the condenser but run more efficiently.
Car A/C system work the same as home system, differences being type of compressor(belt driven, not to say they were not used in home A/C at one time), refrigerant type(R-134a vs. R-22 or R-410), and how the temperature is controlled. Car A/C systems work more like a refrigerator with reheat. The compressor runs until the low pressure control, or manual switch turns it off. The temperature **** blends in warmed by the heater coil. Sizing of a car system capacity is also a lot greater then a house system.