Air Con not working properly?

[mxfive]

Hi All,

My air conditioner in the NA6 is not working properly it just doesnt go cold at all which is perfect timing given our weather at the moment and all the garages are closed for Christmas.

Today it was just blowing the hot air in at 31 degrees. Doesnt matter if I pushed the Air con button in or not.

So right now I am just driving around with the windows down to try and get a breeze as it is too hot inside the car and I am too sunburnt to put the roof down.

I am not a mechanic and know very little about this but I have heard the air conditioning needs to be regassed every so often do you think that might be it?

Its only just had a full service at MX5 Plus and that was for a blown cooling valve and temperature sensor on the radiator which was stopping some cooling fans from working, do you think it might be related to that?

Regards,

Grant

[MX5CHIC]

Just been through all the hassle with my Air Con .. First you need to check if your compressor is kicking in, you may hear a click under the bonnet or your engine labour a little when you press the A/C Button.
Was it working in the past few days or weeks?
Car Air Systems in fact should not require re-gassing - theoretically they should not leak refrigerant at all. Only last week my compressor blew its seal and dumped the entire gas charge (R134a) which is nowhere near as bad for the environment as the R12 Gas which is in older NA"s.
I managed to locate a new compressor and install it on Tuesday and then was lucky enough to find someone to re-gas it yesterday ..... my brand new compressor gives me an air temp at the vents of 0.8 Celcius .... thats so cool!

[mxfive]

Just been through all the hassle with my Air Con .. First you need to check if your compressor is kicking in, you may hear a click under the bonnet or your engine labour a little when you press the A/C Button.
Was it working in the past few days or weeks?
Car Air Systems in fact should not require re-gassing - theoretically they should not leak refrigerant at all. Only last week my compressor blew its seal and dumped the entire gas charge (R134a) which is nowhere near as bad for the environment as the R12 Gas which is in older NA"s.
I managed to locate a new compressor and install it on Tuesday and then was lucky enough to find someone to re-gas it yesterday ..... my brand new compressor gives me an air temp at the vents of 0.8 Celcius .... thats so cool!

Thanks for that. Glad yours is working now. 0.8c

It was working but has never been that cold. It was always only a small cold wind coming out of it. I was going to upgrade it as I would rather have an artic gale force breeze coming out of those vents. My wife drives a Toyota Avalon and the air con in that could snap freeze your fingers to the steering wheel on full force, its the best thing about that car.

[Okibi]

So do you think it's gradually got worse to the point where all the gas is exhausted? Or has it suddenly got a lot worse?

Check you haven't lost your aircon belt and that you hear the compressor kicking in when you press the AC button.

Check your fuses.

[JBT]

It could be a multitude of things causing the problem. Take it back to MX-5 Plus for a check. They will stand by any work they have done to the car.

[mxfive]

Please don't get this wrong I wasnt suggesting that MX5 Plus had done anything to the air con.

I had an unrelated heating problem that I thought might somehow be related as the faulty part was some sort of temperature valve. I know next to nothing about car mechanics so it was just a guess as to what car part might be causing the problem with the air con, so I was just asking a question about this.

I have had nothing but great service from MX5 Plus and Danny is great to deal with, I can highly recommend them to anyone and have done so many times.

[JBT]

Just remember, the MX-5 heater system always has hot water running through it. The hot air flow is controlled by the air flaps/doors as selected on the heater control panel. Make sure it is selected to cold and face level. Does the A/C light glow when you select A/C on?

[mxfive]

Just remember, the MX-5 heater system always has hot water running through it. The hot air flow is controlled by the air flaps/doors as selected on the heater control panel. Make sure it is selected to cold and face level. Does the A/C light glow when you select A/C on?

Yes it is set to cold and face level.

A/C light does come on and it appears / sounds like the compressor is working when you press this in.

Havent checked the fuses yet though.

Im thinking it might have leaked its refrigerant gas out.

[Okibi]

Bummer, what you can also try is remove the glove box and peek behind your radio etc and look at the unit that controls the hot/cold air.

Slowly move the hot to cold know back and forth, you'll see there's a flap that opens and closes.

Sometimes that cable slips (or comes off) and the flap doesn't fully close so while you think it's set to "Cold" there's still some hot air mixing in.

(Sorry I can't remember which side the cable is on).

[MX5CHIC]

More than likely you have lost your refrigerant charge, check the Condenser (in front of your radiator) and all piping for leaks, easy way is to look for an oily residue. It is a requirement for Air Con Mechanics to locate and seal all leaks rather than the old practice of just "topping up" the gas.
Whilst searching for a replacement compressor for my NB I came across some interesting reading regarding the "Sanden"" brand compressor installed in the majority of later model NA"s and almost all NB"s (Australian Models) .......... they are CRAP and prone to failure.
Additionally if you do get a leak and your A/C Mechanic inserts Flourescent Dye to enable visual detection of a leak then your Sanden Compressor is likely to die a much faster death from seal failure. My previous A/C Mech inserted dye 3 times - the Sanden blew it's seals out in a spectacular fashion, best method for leak detection is to use an electronic leak detector.
Sanden Compressors will tend to leak through the seals after quite a few years of service and you may find that after checking for leaks in the most likely place (the condenser) that you may in fact have deteriorating compressor seals.

I instructed my new (and honest) Air Con Mechanic not to insert Flourescent Dye into the system - he agreed.

P.S If you are thinking about fitting a used Compressor - make certain that when it was removed from the previous car that all openings or piping ends were sealed off with a plastic bag held in place with cable ties or elastic bands. Any moisture or dirt that enters will ruin the compressor and contaminate your system. Best bet is to have an old compressor serviced or overhauled prior to using it. My old compressor would have cost $220 to have new seals fitted and more to have bearings etc replaced - I bought a new compressor for $300.

[Okibi]

Great info, i've always wondered if you could improve on the stock cooling system without spending too much.

Are their thicker or better than OEM condensers etc?

I know some people here have insulated the aircon pipes.

I'd love my aircon to be as cold as yours!

[MX5CHIC]

Automotive A/C Systems are designed in a manner that the condenser/evaporator/compressor and TX Valve must "match up" so to speak, placing an over sized compressor or condenser in the system will ruin a perfectly matched system and just won't work, or at least not work at it's optimum level.
The later NA's and NB"s use R134a gas which is less forgiving than the older R12.
The USA uses a different compressor and the US Manual states that air measured from your vents on full return air setting (your vent control to the left) should have a temperature of 6 Degrees Celcius, so I was a little surprised (and happy) that my temperature at the vents was 0.8 Celcius - I measured the temp whilst I was sitting at the traffic lights with the temp outside the car at around 30 Celcius, I was so happy to be in the car on such a hot day and have to turn the fan down to the lowest speed. a first since I have owned the car.
I would suggest that having your existing compressor overhauled or changed over to an aftermarket compressor would be money well spent (aside from sealing any refrigerant leaks first).
I sometimes drive a Corolla Ascent (only if I have to) which has a compressor smaller than the MX-5, but the A/C is just brilliant.

[mxfive]

Automotive A/C Systems are designed in a manner that the condenser/evaporator/compressor and TX Valve must "match up" so to speak, placing an over sized compressor or condenser in the system will ruin a perfectly matched system and just won't work, or at least not work at it's optimum level.
The later NA's and NB"s use R134a gas which is less forgiving than the older R12.
The USA uses a different compressor and the US Manual states that air measured from your vents on full return air setting (your vent control to the left) should have a temperature of 6 Degrees Celcius, so I was a little surprised (and happy) that my temperature at the vents was 0.8 Celcius - I measured the temp whilst I was sitting at the traffic lights with the temp outside the car at around 30 Celcius, I was so happy to be in the car on such a hot day and have to turn the fan down to the lowest speed. a first since I have owned the car.
I would suggest that having your existing compressor overhauled or changed over to an aftermarket compressor would be money well spent (aside from sealing any refrigerant leaks first).
I sometimes drive a Corolla Ascent (only if I have to) which has a compressor smaller than the MX-5, but the A/C is just brilliant.

Thanks for all that great advice MX5CHIC I just checked the fuses and they all looked ok so it is looking more like the refrigerant or the compressor itself. I will look into getting the compressor upgraded. Your assistance has been greatly appreciated.

[MX5CHIC]

Parked undercover I got a real taste of just how cold it gets now ......... revving the engine to 2000 Rpm it got as low as -1.1 Celcius

[Okibi]

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