[TaurusAl]

I own a Ritz VDI and this is my first diesel car. Initially i owned a Santro petrol and Wagon R petrol. I used to notice that whenever I kept the blower on 1 or 2 position, the compressor used to cut-off automatically. I'm sure this has a positive effect on mileage too.

But off-late i have noticed that the A/c of my Diesel Ritz does not trip even when the blower is on 1 position. I took the car to the service station, and the service person confirmed that the A/c does not trip in diesel vehicles as opposed to petrol.

Can the experts please comment if this is true and in this case, is there any point in keeping the blower on minimum to improve the FE ?

[mtnrajdeep]

Yes, in the Swift and Ritz diesels, the compressor does not trip. Found this out when my car was a year old and got it checked from the service center in Bangalore. They confirmed that this does not happen for diesel vehicles. The only use of keeping the blower at minimum is that the air gets cooled more but it doesnt save any fuel.

[falcon009]

Does ac cut-off happens in petrol? I have a ritz petrol but i never noticed cut-off happening.

[mayankjha1806]

Originally Posted by falcon009

Does ac cut-off happens in petrol? I have a ritz petrol but i never noticed cut-off happening.

Yes it does cut off for various reasons. In my old Indica it used to cut off AC when the driver needs more power from engine (i.e. while accelerating hard it used to cut off AC). In my Baleno it cuts of AC after some time when the cabin get cooler (Climate control).

[TaurusAl]

Originally Posted by falcon009

Does ac cut-off happens in petrol? I have a ritz petrol but i never noticed cut-off happening.

Yes Falcon,

I have driven a Petrol Ritz and the A/c does cut-off if the blower is on 1 or 2 position and if the cabin cooling has reached decent levels.

Sad to note it does not happen in Diesel. But why not is the question ?

[anilisanil]

I did not realize this until I drove my diesel figo continuously for 400 odd kms with a/c on. It so happened that the a/c unit started forming ice or something and clogged the blowers because of which the a/c had to be stopped, I though it was some issue and visited the service center and they dismissed it as a normal occurrence and that the a/c would be back to normal once i switch off and switch it on after say 5 minutes.

But not too sure why the a/c does not cut off!

[TaurusAl]

Ok, so now we have reached a conclusion that the A/C does not get cut-off in Diesels, when i asked the same to the service guy of Maruti, he said something like 'The Pump will work less if your keep your blower low'.

I really did not understand what he said. Can anyone put a light on this ? If there is any point in keeping the blower low in a diesel car, and will it save anything at all ?

[Jaggu]

Yes DDiS does not have compressor cut off based on temperature. It just stays ON all the while. I feel this is to avoid the jerks when a compressor kicks in and out. When you switch ON the AC the ECM changes the fuelling in DDiS and compensate for the power loss, also at idle you will see compensation of about 500 rpm.

Long back i had checked with one of the service advisers and they also did not have anymore info than this.

[Figopian]

Originally Posted by anilisanil

I did not realize this until I drove my diesel figo continuously for 400 odd kms with a/c on. It so happened that the a/c unit started forming ice or something and clogged the blowers because of which the a/c had to be stopped, I though it was some issue and visited the service center and they dismissed it as a normal occurrence and that the a/c would be back to normal once i switch off and switch it on after say 5 minutes.

But not too sure why the a/c does not cut off!

Didn't we discuss the "thud" sound that sometimes we hear in Figo is the sound made by the A/C compressor start/stop in the Figo thread? I think this is happening because of the mounts being used in Figos? Now, if that is not A/C compressor being turned on/off what that sound is?

[anilisanil]

Originally Posted by Figopian

Didn't we discuss the "thud" sound that sometimes we hear in Figo is the sound made by the A/C compressor start/stop in the Figo thread? I think this is happening because of the mounts being used in Figos? Now, if that is not A/C compressor being turned on/off what that sound is?

I think that is the evaporator/radiator fan turning on. But yeah you could be right, but I am clueless on why there was "ice" formation if there was a thermostat, I've read other members facing the same issue. But then again, this is my "assumption" and I might very well be wrong.

Edit: I stand corrected. looks like Figo does have a thermostat to cut off the compressor. So this issue is specific to Maruti/DDiS!

[GTO]

Originally Posted by Jaggu

Yes DDiS does not have compressor cut off based on temperature. It just stays ON all the while.

Wouldn't that wear out the compressor significantly faster? Also, the air-conditioner might result in lower FE, relative to other diesel hatchbacks (not that anyone complains about the Swift's FE).

[libranof1987]

This is news!

Is this across all diesels? What's in a diesel car that prompts the compressor to not cut-off ?

And how come it's coming as a surprise to most of us - in the sense, never discussed earlier.

Originally Posted by falcon009

Does ac cut-off happens in petrol? I have a ritz petrol but i never noticed cut-off happening.

A/c cut-off definitely happens in petrol; I've noticed it in all the 3 petrol cars I have.

[Jaggu]

Originally Posted by GTO

Wouldn't that wear out the compressor significantly faster? Also, the air-conditioner might result in lower FE, relative to other diesel hatchbacks (not that anyone complains about the Swift's FE).

Wear tear part is debatable.

A constantly running compressor will wear out sooner than occasionally run compressor, but the part which is most prone to failure aka the compressor clutch will last more if the ON and Off's are less.

FE again, one theory says due to more load it will go down. Another one says cut off will result in temp drop, which in turn results in more work from the compressor when it kicks in. Instead have a compressor which runs constant but in relative lower load (read as temp setting is low), draw back being AC cooling will take more time. So too many theories.

But fact is it (cut off) is not there, why? well the suzuki guys have hit some road block at design that they designed it this way.

Always wanted to know if the same engine in the Fiat also has same quirkiness. Also the vehicle with automatic climate control, how do they work along with DDiS?

Will ask the SA again all these questions next time around.

[libranof1987]

Originally Posted by Jaggu

FE again, one theory says due to more load it will go down. Another one says cut off will result in temp drop, which in turn results in more work from the compressor when it kicks in. Instead have a compressor which runs constant but in relative lower load (read as temp setting is low), draw back being AC cooling will take more time. So too many theories.

But the thing is - when you have the A/c compressor running all the time, it just keeps getting cooler in the cabin which could/would lead many to actually switch the A/c off - effectively having the same end-result, if not worse, that the auto cut-off compressor has.

Also, given the wear and tear part - A/c units with the ACC feature should wear out much earlier than those without, right?

[Figopian]

Originally Posted by anilisanil

I think that is the evaporator/radiator fan turning on. But yeah you could be right, but I am clueless on why there was "ice" formation if there was a thermostat, I've read other members facing the same issue. But then again, this is my "assumption" and I might very well be wrong.

Edit: I stand corrected. looks like Figo does have a thermostat to cut off the compressor. So this issue is specific to Maruti/DDiS!

If you stand outside the vehicle with A/C switched on, you could hear one hissing sound, I am assuming that is A/C compressor sound and it does go away for a while intermittently, that is the reason for me to consider that the A/C compressor goes on/Off in my diesel Figo. Could it be the evaporator/radiator fan? I don't know, if that fan will make this kind of hissing noise.

Also, I don't get why this facility would be there for petrol engines and not for diesels? Interesting to know though!