Car Aircondition Problem please help

[jimmyjewfish]

l am a commercial and domestic aircon guy but never work on cars. My van the cooling is not working but when l switch it to heating works good hot air when l switch it to cooling normal air comes out. Do cars have reversing values do they operate same as normal aircon systems or what else could be the problem its a mitsubishi express 2002 SJ.

Thanks for reading and trying to help :)

[engrp]

sir jimmyjewfish, usually, my experience in vehicles,. the heating system is not an electric heater core. but the hot water coming from the vehicle passing thru a heater core, and a fan blows on the heater core, thereby providing the vehicle with heating,. the aircon system is an entirely different system, employing a different set of components. maybe the reason why your heater is working and the cooling is not. only my opinion.

[doormaster2008]

The air con system is totally separate from the heating system.you can pick up a pair of access vaves from your local fridge spares wholesaler and check the gas.you will see the compressor mounted by the engine.it has a clutch on the front of it.follow the pipes and you will find the access fittings.if there is no pressure,pressurise the system and check the condenser.it is mounted in front of the radiator.more than likely hit by a stone or something.

[BranscumHelen]

I think that you should study the Ac book manual and then operate your car AC.

[nevinjohn]

Probably theres a gas leak in the system. . . Also, see whether the compressor is engaged once the AC is powered ON. Do this when the engine is idle. You should feel the raise in engine rpm(look at the meter), if that doent show anything open the bonet, see whether the compressor is getting engaged. If not, probably the compressor clutch is damaged. If this works fine, theres a leak in the sysytem.

[R717]

Yep, cars have separate systems for heating and cooling, cooling by A/C and heating by hot water straight from the engine's cooling system.

This is done so you can have the heater and the A/C on at the same time. That sounds ridiculous but that combination is used on cold rainy days when you want to demist the windscreen fast. The A/C dehumidifies the air then the heater core warms the air up. The heater is vastly more powerfull than the A/C.

Yes check out the clutch and see if the compressor is running, if it is you more than likely have lost charge due to a leak in any number of places, as auto A/C systems are made up from dozens of components bolted together unlike residential A/C.

Look for the oil !!

Or charge with some dry nitrogen and go over the entire system carefully with soapy water.