[a4anurag]

Originally Posted by saket77

Unless humid, why are you using the heater with the AC?

Buddy, he is not using the AC but the car is giving out cool air even when the knob is kept in medium temperature setting. There is an issue with the HVAC system of the car.

If I am not wrong the temperature knob was set like this in the picture below?

Originally Posted by rohan_iitr

That is what is happening in my car. I am getting cold air at medium temperature setting and medium temperature air at the highest temperature setting.

Am I right Rohan?

Anurag.

[rajeev k]

Originally Posted by rohan_iitr

If the coolant level is low, the heater core will not generate sufficient heat and the AC will give out cooler air that expected at the particular temperature setting.

As long as there is coolant in the reservoir there will not be air or voids in the coolant flow and therefore the effects has to be just the reverse. Because the lesser quantity of the coolant would force it to carry more heat.

[saket77]

Originally Posted by a4anurag

Buddy, he is not using the AC but the car is giving out cool air even when the knob is kept in medium temperature setting.

Oh...ok, if he meant HVAC system. I thought he is using the AC with heater. I have seen a lot of people switching on the air conditioner with the heater- always!

[a4anurag]

Originally Posted by saket77

Oh...ok, if he meant HVAC system. I thought he is using the AC with heater. I have seen a lot of people switching on the air conditioner with the heater- always!

But I guess the whole coolant has to be drained, system to be flushed clean and then the fresh coolant must be pumped in to check for the behaviour of the HVAC.

Anurag.

[rohan_iitr]

Update : I took the car to the H.A.S.S. this morning for a full service. I mentioned about the low coolant issue.

They checked for leaks, but didn't find any. So, it seems that the quantity of coolant filled in the last service was not sufficient.

I asked them to top it up. I will observe the coolant level now onwards.

Hopefully, this will also take care of the air conditioning issue.

By the way, what do you guys mean by using the heater ? Are you referring to the rear defogger ? My car doesn't have a rear defogger.

I was referring to the setting of the temperature control knob as shown in the figure above. My usual settings are quite similar:
- Temperature control knob in the center
- AC button switched on
- Recirculation mode selected
- Blower at first position
- Direction of airflow - on the occupants' face

Rohan

[zoombiee]

Originally Posted by rohan_iitr

They checked for leaks, but didn't find any. So, it seems that the quantity of coolant filled in the last service was not sufficient.

Check the coolant level in the morning after the service is done or may be even a day later. Sometimes, due to airlocks, the level in the reservoir tank may seem high, but once the air moves out, the level goes down. This happens quite commonly with Palio's atleast.

[rajeev k]

Originally Posted by rohan_iitr

My usual settings are quite similar:
- Temperature control knob in the center.

It is ideal to keep the temperature knob within the green (cold) zone for normal driving except during winter.

[a4anurag]

Originally Posted by rohan_iitr

By the way, what do you guys mean by using the heater ? Are you referring to the rear defogger ? My car doesn't have a rear defogger.

The heater is the left-side knob being pointed on the RED zone gets hot air in the cabin.

Originally Posted by zoombiee

Check the coolant level in the morning after the service is done or may be even a day later. Sometimes, due to airlocks, the level in the reservoir tank may seem high, but once the air moves out, the level goes down. This happens quite commonly with Palio's atleast.

Air lock will come into picture if,

1) there is a hole/leak that could suck-in air,

2) if the coolant reservoir runs empty which could suck-in air.

I don't think any of the above instances have been seen by Rohan in the car.

Anurag.

[pzkfg6]

A cm down in 7 to 8 months may not be an issue I hope. Do you smell coolant inside the car? how many kms you did during the period. Another possibility it may have an internal leak and could mix up with engine oil. Does the coolant reservoir have traces of oil?

[a4anurag]

Originally Posted by pzkfg6

Another possibility it may have an internal leak and could mix up with engine oil. Does the coolant reservoir have traces of oil?

I still doub this could be the issue as I did mention the same in my earlier posts.

Anurag.

[sandeepmohan]

Originally Posted by rajeev k

There is no direct relation between the Air Conditioner performance and the coolant level in the reservoir.

True but a continuously failing air conditioning system is a sure shot sign of an engine that is about to overheat/steam. When I say air conditioning failure, I mean a sudden stop in cooling for a system that has been working perfectly all right.

Many years ago, I was assisting an elderly gentleman for some household chores. He always insisted we take his Wagon R. He did warn me about the mysterious coolant disappearing problem every time they took the car out. As usual, I popped the hood and found the expansion tank empty. I filled it up with tap water cause that is all there was. We headed out. The temperature gauge was registering normal temperature. A good 15km later the temperature gauge dropped to Cold. This did not look right. Reached our destination and popped the hood to find no water in the expansion tank. A lot of heat radiating from the engine. It was probably on the brink of steaming. I topped up the expansion tank again. All the water had evaporated when we got back home.

Over the course of time and being in touch with this gentleman, I was told the service centre was not very competent to find the root cause of the problem so he gave the car to a reputed local garage. The local garage lifted the head and found blocked water jackets around the engine block. Mineral deposits from all the tap water being filled, over the period of months, years blocked the tiny passages for water to flow around the engine block. With excess heat build up around the engine block, steam was pushing water out from the over flow pipe on the expansion tank. You could never find a trace of it anywhere nor was water leaking from what we thought was some hose.

The first generation Wagon R has a poor design with regard to the temperature gauge. It works only when there is water/coolant in the system. If there is none, it shows cold and might make you think the gauge or some sensor is dead. The next time you see a non functional temperature gauge, don't ignore it unless you are absolutely sure about how your engine cooling system functions.

I don't suspect the above happening to you but it is a possibility.

[mmxylorider]

Since what is filled as coolant is essentially a concentrate + water, with usage and high temperature, wouldn't there be some amount of water loss from the mix?

I would also check if the radiator is full or not by opening the radiator cap - ONLY on cold engine.

[rohan_iitr]

Update : I gave the car for a full service this weekend. I asked them to investigate the low coolant issue.

The service advisor mentioned that they found some trace of moisture near one of the coolant hoses. But it can't be termed as a leak.

They have topped up the coolant for now and told me to keep an eye on the coolant level and temperature guage. I will be doing the same.

Thanks for all the replies guys.

Rohan

[sandeepmohan]

Originally Posted by mmxylorider

Since what is filled as coolant is essentially a concentrate + water, with usage and high temperature, wouldn't there be some amount of water loss from the mix?

Yes; there will be some evaporation. The amount of evaporation will vary based on driving conditions too. As an example, my car sees very little running and most of the running has not been in extremely hot weather conditions. No change in coolant level in the expansion tank in over a year.

A lot of cars do not come with a radiator cap these days. The coolant expansion tank is the only way to check.

[wanderernomad]

If there is no coolant in the expansion tank and there is no radiator cap, how do you check if there is coolant in the radiator or not. If you just topped up the expansion tank will it be the right procedure? My normal temperature indicator is not working but when I switch on the AC the temperature reading starts to work.