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Low Mileage whenever AC is switched on

Discussion in 'Engine Compartment' started by avnsiva, May 2, 2014.

  1. avnsiva

    avnsiva Amatore

    Messages:
    140
    Chennai
    Off late I could see that whenever I am using AC, the engine seems to be strugling and the mileage drastically decreases.

    There is no problem with the cooling efficiency of the AC.

    I could also see that water is leaking below the radiator whenever AC is on. But once I switch off the AC, the leakage also stops.
    There is no drop in the coolant level as well.
    There is an increased noise and vibration when AC is ON. But thats usual right?

    What could be wrong here?
  2. pabhishek

    pabhishek Esperto

    Messages:
    1,381
    Oslo
    Pune
    Linea T-Jet
    Hi Avnsiva,
    A/c definitely increases the load thats the reason engine struggles and sounds a bit harsh too while A/c is on; more so if gears are not chosen wisely. A bit of Drop in mileage is also normal. How much drop is in your case?

    As cooling is fine, so nothing to worry I guess. Water leaking on the floor during A/C operation is also normal.
    1 person likes this.
  3. avnsiva

    avnsiva Amatore

    Messages:
    140
    Chennai
    When I cruise at 80 in 5th Gear, with AC, the Instant Consumption shows 19-20. Without AC, the instant consumption reading shows 26-28.

    Also, the water is leaking from the AC drain outlet and from a tube below the radiator fan.
  4. pabhishek

    pabhishek Esperto

    Messages:
    1,381
    Oslo
    Pune
    Linea T-Jet
    Please dont consider IC, it varies highly. Instead note the average mileage of 2 separate trips with more or less same traffic condition with and without A/C on. Then Compare.
  5. momu

    momu Timido

    Messages:
    1
    chennai
    Even I am having the same issue. My avg mileage is showing 11.8 km/l. Is this correct? I thought it should show 13 at least.anything can be done abt it?
  6. pabhishek

    pabhishek Esperto

    Messages:
    1,381
    Oslo
    Pune
    Linea T-Jet
    Its absolutely normal depending on the traffic condition.

    Happy Riding!
  7. avnsiva

    avnsiva Amatore

    Messages:
    140
    Chennai
    I checked my AC in this way. When the car is stationery, i pressed the accelerator to maintain the RPM at 1500 for some 10 seconds. When the RPM holds steady around 1500, I switched ON the AC. I noticed that there is a dip in the RPM the moment AC is switched ON. The RPM came down to 1200 and then climbed back to 1500.

    I repeated this process when keeping the RPM at 2000. This time the RPM came down to 1700-1800 and climbed back.

    Since the cooling effect is good, I assumed that the compressor is exerting more load on the engine. Also since the compressor has become noisy, I assumed that may be the NC8 oil inside the compressor needs to be topped up.
    I went to a nearby AC mechanic in T.Nagar and asked him to top up the NC8 oil by 50 ml and reload the regrigerant.

    Subsequently, I have driven for around 300 KM's. The Compressor noise have come down and the mileage has improved as well.
    1 person likes this.
  8. Johnycomelate

    Johnycomelate Novizio

    Messages:
    37
    Kochi
    Hi pabhishek, My T-jet 2011 shows a dip of mileage by almost 2 km when AC is on ! Hope it is normal ?
  9. pabhishek

    pabhishek Esperto

    Messages:
    1,381
    Oslo
    Pune
    Linea T-Jet
    Hi Johny!! usage of ac drops the average mileage of any vehicle by 1-2 km/l . Its absolutely normal!!
  10. vista7155

    vista7155 Regolare

    Messages:
    311
    bangalore
    Hi,
    whenever the AC is on in MJD 75ps it struggles to pickup from 2nd gear.
    For example if there is slow moving traffic and if i am travelling at 20km\hr with AC on it struggles to move it doesn't stall but it will move very slowly it is quiet annoying, couple of times i have missed rear ending very closely.
    Once AC is switched off it is normal moves in very good speed.
    Is the above observation is a issue or normal.
    please confirm.

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