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Faced a wierd problem while returning from Pune 3 days back in my Alto.

While travelling on the old NH4, noticed that the temp gauge (which is typically at the half-way mark) started indicating temperature towards the top end of the scale. Stopped the car immediately. Had started the journey just 8-10 minutes back, so hopefully I noticed the overheating pretty early. I let the engine cool down, the radiator fan was working at full blast. Checked the coolant container and it had coolant upto the 'Full' mark. The coolant was there, the radiator fan was working and I was crusing pretty sedately (~80-90 kmph in the top gear). So what was the problem because of which the engine overheated?

My limited knowledge took me only this far, so hunted for a local mechanic. He opened the radiator cap and no boiling water/steam escaped. He mentioned that there is no coolant in the radiator and although there is coolant in the coolant-container, it is somehow not taking it from there. He topped up the radiator as well as the coolant-container with plain water, took a test run and the problem seemed to have been resolved. I drove back cautiously with my eyes glued to the temp-gauge (which was showing slightly below the half mark).

Searched tbhp for related threads and planned to take the car to the M.A.S.S today. When I steped in the car today morning, noticed a foul smell and the carpet edges were looking wet. First suspect was the car-washing-guy, checked the door-beadings, but they were dry. So the water did not come from outside. Lifted the mat and noticed that what I initially thought as water, was in fact a mixture of water and coolant. It had a distinct blue shade and there was quite a lot of it (at least 200-300 ml) in the footwell. Checked the coolant level again, it had dropped, topped it up with water and went to the M.A.S.S. directly.
The SA did basic investigation and told that the heating coil (part of the AC assembly) seems to have been shot/cracked. The estimate given was as follows;
1. AC Servicing (dash removal, AC removal, gas refill, Nitrogen, labour etc) - Rs3800
2. Possibly replacing the heating coil - Rs 2200
3. Carpet removal and refixing - Rs 650
4. Internal shampoo to remove coolant and its odour - Rs 1000

Overall ~8500 Rs including taxes etc.

I believe that the charges are on the higher side. Any similar experiences and opinions? Should I explore the option of a local mechanic?

Check with a Local AC guy who specializes only in Car AC's. That will be cheaper no doubt. Rs 650 for removing carpet is way to expensive along with the Shamppo treatment.

Must be the heater/AC box. Check it out.

Its definitely the heater coil. Faced similar problem with my cousin's alto couple of weeks back.

Darshan, do the estimates look pretty much in the range? Or was it repaired at a local mechanic?
Thanks

SDP, Do we really need the heater in mumbai? If you feel we don't then you could just blank off the hose pipes that go to the coil, in the engine compartment itself. I think you can just route one pipe, from the outlet on the block to the inlet on the block. You will save the money too. I would do it.
An AirCon or local mechanic will do it for you. This coil is seperate from the Air Con Evaporator.
Cheers

P.S. Right you are Jaggu

Yes you can actually disconnect and blank the heater line if you need to keep the cost low.

The question is why no boiling coolant in the radiator. Did the thermostat fail/did not open fully causing the coolant temperature in the engine block to rise. This would explain the temperature gauge indicator. In the closed circuit of the engine block, the only other fail point is the heater core. The heat notch of HVAC opens the heater core and allows hot coolant to flow through which is then pumped over with air causing hot air flow inside the cabin. I'm guessing this is where the leak due to hot under pressure coolant occured and spilt inside. It would be wise to check the thermostat to see if that is working properly.

On a related note - in case one observes a rising temperature of the coolant via the guage and if the car is equipped with HVAC -shut down the engine, switch to heating mode, outside air, open all windows and switch on blower full blast. This is effect allows the heater core to act as a mini radiator to disperse the heat and cool down the coolant a bit faster.

Thank you guys! Did not really think this could be an option. If the heater-coil needs replacement, most likely I would go with your suggestion.

heater coil is made of aluminum, It does not rust. So it giving away in the coil area is rare. AT the joints maybe, but that too are pretty well build.
Are you sure its the coil and not the rubber hoses, that gives away easily.

Anyway.
Price quoted is way too expensive. Take it to an AC specialist. IMHO the Job should cost not more than 2500/-.

@ SDP - As of now its disconnected, as there is not much use of heater. Regarding the estimate, i am sorry i have no idea.

SirAlec, was going to reach out to you based on AJ's pm. Thanks a lot for the insight and the ball-park estimate.
Sir, one more question. I was told by the SA that he needs to remove the entire AC assembly, remove the AC coil, release the gas to be able to reach the heater coil. Is that correct? (Seems like a non-maintainable design)
If the problem is not found at the joints/rubber-hoses, I might not opt for the full investigation of the leak and would rather go for disconnecting the heater coil instead as suggested by others here. Thanks again

Thanks Darshan. Disconnecting the coil is coming out as a practical solution if the leak is somewhere deep inside. Would most likely opt for the same.

What i will advice is a sure shot practical way to sort out the coil leakage.
Unfortunately cooling coil and the heater coil is in the same plastic housing in almost all the cars. So to service it (read, cleaning the fins) you have to remove both. But to check the either coil for leakage you don't need to remove them. As there are no joints inside, its made out of single aluminum pipe.

Here is what you do.

1. Put the switch in hot position, if its magnetically operated like in Ritz (don't worry ALto has cable operated one) put in hot position before removing coolant pipes.

2. Disconnect the coolant in and out pipe (check image for illustration) put a jet of water inside one of the pipe (in or out any one will do) and a finger in the other. You might want to put a polythene bag or newspaper below the dash before doing this. If you see water or coolant drops inside the cabin, you are screwed, you have to change the coil in that case.

Its expensive but there is a workaround. In india there is Juggad for everything. Visit any kabadi who deals in insurance total loss cars. Alto is pretty common you will get heater coil for as low as Rs.500/-. I am sure mumbai has many similar place.

To check coolant leakage through hoses is easy. Park the car overnight after a bit of driving on a clean surface (cemented parking). If you see drops of coolant on it, its definitely hoses and joints.

BTW is the radiator and its cap checked.?


This is a modification i did on my old 800 long ago.

So, if one pulls off the longer tube and makes a U type bypass on the inlet & outlet of the coolant pipe, the heater is blocked off(?) and the car can be driven normally

lolz! No man you got it completely wrong. this pipe is for letting in/out coolant to and from heater coil. You have to block the T pipe from main coolant line that goes to the block and back to radiator.

Something like this.