[250Nm]

The Problem:
With more than 110K on the odo in the 8.5 years of my 2016 Tiago, it started to show AC issues in the past few weeks. While the unit itself appeared to be working fine, there would be suddenly no air from the vents after about an hour of driving (read AC running). I could hear the blower motor noise as well as the compressor kicking in but no sign of air or cooling from the vents. There was also ice formation in the passenger footwell area where the air filter and evaporator coil are located.



Workshop Visit:
As with most Tata owners, I was afraid to visit the ASC and took the car to an FNG AC workshop along with a friend of mine. The moment they heard my car's age & odo, they were certain that the evaporator coil (also called as cooling coil) would have clogged with dirt and needs cleaning. This has more to do with TML using a mesh filter which allows fine dust to pass through, unlike paper filters used in most cars these days. They also hooked up a pressure gauge to the low pressure port and found the pressure be fine:




A quote of 6K was given to us, requiring 3 to 5 days to remove the dashboard, then remove the coil for a thorough cleaning. I was apprehensive of getting scratches & damages to the dashboard plastics in this process. After some discussions with the FNG owner, we left the place, asking some time to think about getting the repair work done.

DIY Idea:
Later that day, my friend looked up a few YT DIY videos and shared one of them where a coil cleaning liquid was sprayed onto the coil from the "air circulation" vent located near air filter. Rather than using a spray, my friend suggested using just air compressor to clean the coil before finalizing the FNG visit. One fine evening, I drove up to his place where he had access to a small industrial air compressor and attempted the process.

Cleaning Process:
First we removed the air con air filter using the Taparia 974 stubby screw driver which I had bought only for my regular filter cleaning activity. Then we used the compressor gun from the air circulation vent (from the side) and air filter opening (from the bottom). Since I had driven ~10km to his place, the coil already had moisture on it thereby helping with the dirt to loosen up and fall down on the carpet area. We placed a waste cotton cloth on the floor to prevent stains on my stock carpet which had no floor matting. After about 10 minutes we inspected using phone camera and found the coil it to be much cleaner than before. Tested the AC for few minutes and again used compressed air for a final ~5 minutes before re-installing air filter.

Before (missed to click a clear picture):


Air gun (from the side):


Air gun (from the bottom):


Notice the dirt on the floor area from the cleaning process:


After:


Here is a pic from another Tiago owner from our social media group with his 6 year old Tiago:


Outcome:
Right after the cleaning process, I observed much better air flow (almost 2X) through the vents and felt happy about our attempt, despite not being the permanent solution. To ensure I did not feel a placebo effect, I did not inform this activity to better half who immediately felt the chilling air flow and even reduced the temperature knob that was never touched for a long long time .


Learnings:
I learnt a few basics of car AC systems and got an opportunity to get my hands dirty in the process of cleaning the evaporator. Also saved ~6K and avoided scratches on the dashboard. I have driven around 1000 km since then and did not face the issue yet. Will continue to observe the performance, especially during long drives and update this thread.

While this may be a temporary solution, it worked quite well for me and and went ahead with creating this thread, which might help others. Looking forward to BHPians' comments on this approach and pitfalls if any so that corrective actions can be taken.

Drive safe!

[GTO]

Thread moved to the DIY section. Thanks for sharing!

Going to our homepage this weekend

[Prowler]

The fins are not as close as that of the current domestic Inverter ac coils. That is a good thing in this case as compressed air can easily dislodge the accumulated dust.

In case if it becomes stubborn, you can use a battery operated pressure washer to clean with water.

[lemedico]

Originally Posted by Prowler

The fins are not as close as that of the current domestic Inverter ac coils. That is a good thing in this case as compressed air can easily dislodge the accumulated dust.

In case if it becomes stubborn, you can use a battery operated pressure washer to clean with water.

Sir, using a pressure washer inside the car isn't recommended. What a mess it will make, apart from soaking all electricals in the vicinity
I have a Tiago as well, my next DIY will be to air blow the gunk, and then use ac cleaning foam to dissolve as much as what remains

[steadfast]

Doing this exercise even without having an estimate of price, time and process by Tata ASC does not seem to be a complete research done before picking this DIY unless I am missing something here.
Or may be your experience with Tata ASC has been so bad that you did not bother asking them

[Ravi Parwan]

Using pressure gun on AC coils is contra indicated. These run on very high pressure. You are lucky you did not damage your coils as this high pressure can easily deform the fins and even the tubes of the evaporator.

A pressure water gun would be even more dangerous. Better would be to get a can of the AC evaporator coil cleaner which contain some kind of Mild acid which causes the dirt and grim to bubble out of the coil.

Since your car coil is relatively easier to access (read visible) try spraying some of that coil cleaner and you will get much better results. All cautions for using the acids apply. Spread lots of newspaper on the floor before proceeding.

[250Nm]

Originally Posted by steadfast

Or may be your experience with Tata ASC has been so bad that you did not bother asking them

It is the latter

Originally Posted by Ravi Parwan

You are lucky you did not damage your coils as this high pressure can easily deform the fins and even the tubes of the evaporator.

Thanks for the tip. We did discuss the possibility of damage before using air pressure. We proceeded with the DIY only after verifying that the gun cannot actually get too close to cause any damage.

[JediKnight]

Originally Posted by 250Nm

Workshop Visit:
As with most Tata owners, I was afraid to visit the ASC and took the car to an FNG AC workshop along with a friend of mine.

One of the benefits of owning a TATA is you learn a lot about cars . You need to be hands-on as a TATA owner. All the best.

[Mortis]

You should take this DIY a step further by cleaning the coil with AC coil cleaning foam

[gopa99]

Good experience shared, and while this is a step in the right direction some care ought to be taken to not damage the fins and the air flow path.
While using a direct blow from an air compressor you run a risk of dislodging an otherwise loosely clinging muck deeper into the fins which can further impede the air flow.
Using high pressure water is an absolute No as the fin orientation can get altered permanently damaging the air flow path.
Using a very basic(high pH >8.5) cleaner too can post issues of pitting damage on Aluminum coils.
And the last word of caution is to ensure the evaporator drain plug is clean and not choked by your cleaning as else it can impede the condensate water drain off and risk getting your floor carpets damp while the AC is running. You can do this by removing the flexible hose that sticks out of the coil box and cleaning it and the drain path through, using a flexible wire. Happy cooling!

[White bird]

[quote=Ravi Parwan;5912663]Using pressure gun on AC coils is contra indicated. These run on very high pressure. You are lucky you did not damage your coils as this high pressure can easily deform the fins and even the tubes of the evaporator.

"A pressure water gun would be even more dangerous. Better would be to get a can of the AC evaporator coil cleaner which contain some kind of Mild acid which causes the dirt and grim to bubble out of the coil. "
Most evaporator coil cleaners contain phosphoric acid that is highly corrosive. The coils have to be rinsed properly with water after treatment. Improper use will not only destroy the coils but also any metallic parts of the car that comes in contact

[Prowler]

Originally Posted by Ravi Parwan

Using pressure gun on AC coils is contra indicated. These run on very high pressure.

Not really as it depends on the type of pressure device. I have Bosch 100 A (or whatever) which puts out about 100 bar pressure which will cause damage to the fins. The pressure forces the gunge and stubborn dirt from the body of the car/wheels/pavement.

There is another smaller handheld battery operated washer which has about 7-10 bar pressure. This is what the AC technicians use to clean the IDU. This is safe enough.

Use a plastic sheath like they use for covering the electronics in the IDU which comes with a pipe.