I have L200 Mitsubishi quite old but still running. I experienced a leak sound and soft blow sound accompanied by smoke in my engine. I then turn off the engine immediately and open the hood and I did not see any smoke after that. I was scared that my engine overheat and won't run but luckily the engine seems fine. However, the AC is not blowing cold air.

I also notice that when I turn on the aircon the compressor is not engaging and there is no idle up. The blower is fine yet the AC is not blowing cold air and the engine is not increasing the RPM which in the past work. Every time I turn on the AC the engine increase its RPM and now it is not working.

I hope some of you have experience fixing this kind of issue. The coolant in the radiator seems to be working fine but I'm not 100% sure. The temperature gauge too is not working but when I bypassed the socket (temperature sending circuit/sensor) the gauge is going up.

As of now the temperature gauge is not working. I hope someone can give me guidance.

  • Welcome to Motor Vehicle Maintenance & Repair! Dec 19, 2023 at 15:27

1 Answer 1


More than likely your AC suffered a catastrophic failure in the lines which has caused the refrigerant to discharge into the atmosphere. This is most likely the "smoke" you saw coming from under the hood. It would also be why you didn't see anything once the hood was opened as all the refrigerant had dissipated at that point.

You'll need to take your vehicle to a shop where they can find where the AC system decided to "pop smoke", get it fixed, vacuumed, and then recharged. Depending on how old it is, it may also need to be converted from R12 to R134a refrigerant in the process in order to work again.

  • thank you. I might be looking in the wrong place after all. I already ordered a coolant temperature sending circuit as this was advice by a mechanic I know.
    – Jeo
    Dec 20, 2023 at 15:59

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