Non-Wood: DIY Car AC Coil Cleaning

In recent times, I noticed a few things about how my car’s AC was not performing as well as it could. Some of the problems were:

– During a long drive with AC on full speed, I suddenly found no air coming out of the vents even though I could hear the fan/blower working. After switching off the AC and driving 10-15 minutes in the boiling Indian summer, I tried the fan again and, much to my relief, I could get the  air back. (In hind sight, I suspect the AC “coil” might have frozen over with no space left for the air to flow through)

– As soon as the AC was switched off, I got a muddy smell from the AC which was not at all pleasant and forced me to switch on the AC back again or roll down the windows

– When I switched the air intake in the car from outside to “re-circulate”, I got a hissing sound as if the air was being sucked in from a small opening.

What prompted this DIY was the Rs 3500/- estimate which the Car service center gave me when I told them about my problems. On asking for more details, I was told that these high expenses were required for doing a “full AC servicing”. This entails taking the dashboard of the car out, removing the “gas” from the AC, removing the AC itself from the car and then putting everything back in and refilling the gas.

I was taken aback about this procedure because I did not expect that just a cleaning of AC should require its removal from the car’s body. More over, the AC was still working perfectly, meaning there was no reduction in cooling per-say so I was not convinced about the removing/refilling of the AC gas. There was also a big no-no about taking the dash board off. No matter how professional the workers, they cannot put the dashboard back with the same robustness as it came factory fitted, I was convinced it would lead to a rattling dashboard.

So I checked for more information on the internet and here is what I found.


As basic information, a car’s AC is just like a split AC we have in our homes. The external part which throws hot air is located near/next to  the car radiator; that is the grill part at the front of the car.

Inside the car are the cooling coils, a mesh like metal structure which gets cold, the air flows through it turning cold and then coming out the car’s vents. These are located near the passenger side foot area. The adjoining photograph is of a Maruti Suzuki WagonR. I hope other cars have similar arrangements.


The air inlet is covered by a plastic frame and there is no mechanism to remove it. Also, it is a bit high up behind the glove box which meant I had to lie on my back and see through the opening to have a look at the coil.

The sight was not good. Using a small flashlight, I could see that most of the surface of the coils was covered in greasy mud. The aluminium metal used in coils is very fragile and it is quite easy to bend them, as I found out when I tried to use a screw driver to try take some mud out.


Almost two thirds of the coil was blocked with mud. I am a regular user of the car AC and although I clean the car from the inside every week or so, it was surprising to see leaves inside that area. There is no good way to remove that stuff. A long tweezer, 15-20 minutes and a blister on my thumb later, I had removed a handfull of leaves from that area. I am sure there could have been an easier way (maybe a small pipe in front of a vacuum cleaner) but I did not have access to it.

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Searching on the internet for a medium to clean the coil, I came across CVC coil cleaner. Cost me around Rs 425/- including shipping from a shopping website. Surprisingly, none of the local Car AC servicing shops had one of these, possibly to discourage anyone trying this on their own and losing out on business.

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The can came with a long thin pipe. It helped me in getting the spray to reach as close to the coil as possible. I got a few good presses of the spray and had a look again. The spray immediately turns into thick foam, almost the consistency of a shaving foam. Then slowly it starts turning into water.

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Ten-fifteen minutes into the process and the foam turns into water, taking with it a lot of grime and dirt. You should then start the car and switch on the AC at full speed. It helps more condensation to form on the coil and thus helping the draining of more residue.

I sprayed on the top portion and took the picture (above-right). You can see the way the dirt is flowing down. I emptied around half the contents of the can. I could have used up more to reach a better clean state but saved up on the can so that I could use it in my father’s car.

Before – After


The air flow has definitely improved. There is no more the hissing sound which was coming earlier. The muddy smell is gone as well.

I am not sure if there would be any impact on the AC unit itself but for sure the overall performance of the AC has improved.

I am sure something similar can be done with a home AC without the need of physically taking the unit out. Have you done anything like that? Do share.

More so because the humid Indian Summer must be taking its toll on your AC and your electricity bill as well 🙂

Thanks to people at Team-BHP where I found lot of how-to’s and articles on this topic.


About Writer

Being based in India, I will focus primarily from that perspective.
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