Air conditioner issues - 308 QV

Can you tell if the compressor is still running when it quits blowing cold? If cold air stops abruptly but the air is still flowing, it sounds as if the compressor cycled off.

Also, although the symptoms do sound like possible freezing up, when an evaporator freezes up, the vent airflow also drops conslderably or even stops because ice forms and clogs the passages. So if it's still blowing from the vents with the same force whether cold or not, it is probably not freezing up.

Compressor could cycle off due to either too much or too little refrigerant in the system but usually that happens much more quickly than after 30 minutes. Could also be a faulty low pressure switch or an intermittent connection at that switch.

 

I'm not an expert, but it sounds like your friend is right. Classic freeze up symptoms. Try running it with the fan on high, but the temperature set on a not quite so cold setting (I assume you were running it on the coldest setting). Try it at 50% or 75% and see if the problem goes away.

 

There are two controls for the air conditioner. One for fan speed and the other says 'Off-Temp' with a 270° rotating knob. This the component which connects to the evaporator through a tube to sense evap temperature. It releases the a/c clutch when the evaporator starts to freezes up. It can go bad by virtue of a broken tube and give the symptoms you state.

More than likely you have just cranked it to 'Max' temperature thinking the air would thus become colder. Doesn't work that way. If you have been keeping it at 'Max', dial it back and use the a/c at half or less rotation for a while...the coldness of a/c air temperature isn't affected, i.e it will be just as cold at low as at high. But it needs kick off periodically to allow the evaporator to warm slightly and not freeze up. Modern a/c units do this automatically. Think of yours as a 'Ferrari Manual 3 Speed Air Conditioner'. And be happy you have one that blows cold.

 

If you have moisture in the refrigeration system,then it may be iceing up the tx valve orifice and pump your sytem down,which in turn stops the system in LP(low pressure).Then when the ice melts it makes the LP switch and the system starts again until it ices up again.To fix this you would need to decant the gas,replace the drier,dehydratenthe system and recharge.

 

Do a search, I think the expansion valve is the same one used on a Mazda car. Cost about $40.00. Drier, take to an A/C shop and get one that matches. Probably $30-50.

Good luck

 

I have never seen a cross ref for the expansion valve though it has to be something generic since Ferrari never made expansion valves.

The receiver dryer is common and has been referred to several times in various posts - a search should turn it up. I think it's around 30 bucks.

Without a firm cross reference, only way I can think to match the expansion valve is to pull it and take to a shop, claim it's from an aftermarket ac system installed in an old car (pick any old car you like) by a company no longer in business and see if they can match it.

Also - the valve may have a manufacturer part number on it which may do the job (Not a Ferrari part no)

 

I posted this recently, should help with the expansion valve. Jeff

http://www.ferrarichat.com/forum/showpost.php?p=140323060&postcount=237
Image Unavailable, Please Login

 

Good Job!

 

Well - good for the 308 folks anyway! I just noticed that the 328 exp valve is different so I'll have to keep looking.