Need Advice,AC does not work, 1998 550 any thoughts.

I know it is a long shot, but you do have the "OFF" button on the lower-left part of the HVAC controls pushed OUT, true?

If you push that "OFF" button pushed in, then the a/c is turned off and fresh air is piped into the car.

On a hot day, then the "OFF" button makes it seem like the a/c is broken.

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I have been having the same issue. Replaced A/C clutch. Now drawing too much amps and blowing fuse. Checking the blower motor next.

D

 

couple quick things. If you suck the system and it will not hold vacuum then you got to find the leak first or nothing you do will work. Lets say you can hold a vaccum then you can try and recharge it. if the vents are not blowing cold during fill and the compressor is on you got problems. Sometimes the ssytem has a feedback sensor that does not allow the compressor to kick in if the freon level is too low as during the initial recharge. However, I have sucked a 550 system to over 1 atm and fired freon into the system and always got the compressor to work no problem and cold air to almost immediately flow. The smell you got is a puzzle. But one of the weirest nastiest smoke odors is buring wires. You might have fried someting in your ac system like the compressor clutch. It is possible to have water in the system and then the compressor tries to compress that and can't and then dies. Oh and since I'm a diy'er and me labor is free I don't mind doing the wrong thing. So I always disconnect reciever dryers during refill attemps and dry them at 250*f in the kitchen oven for an hour to drive off the moisture then put them back in and suck the system. I almost never have to do this job. I recharge maybe one of my cars every few years. New systems are almost leak free. Ferrari systems are lame. Lots of controversy on use of stop leaks in systems. The dirty little seret is stop leaks work and many pros will not admit to using them. I use them in crappy cars like ferrari's and porsches because no ferrari or porse is as good as japanese or gm even if they try and use a japanese compressor the italians always and sometimes the germans will always screw it up.

 

John, how about clarifying this a little. In one post you say you have no cold air at all, and the next post you say you can feel ice cold air. Which is it?

 

John, with due respect to my buddy FBB, I wouldn't use any stop leak stuff in this system because of the type of compressor you/we have. Its variable displacement feature depends on a mechanical control valve on the back of the compressor to be working, and if that control valve gets gummed up with stop leak and quits working, then the system will never work right.

So this style of compressor runs with the clutch engaged all the time, instead of cycling on/off. In theory this is better for the system than loading/unloading via the clutch. The only time the clutch disengages is when there's insufficient freon in the system and the pressure switch drops it out to avoid burning up the compressor.

 

John is 100% right. But at the same time practically that is not reality in the ac world. Ferrarri and a few others are "special" meaning really lame. 40 years of ferraring and still I have never seen a ferrai ac as good as a 70s gm unit. All makes have gotten better with Ferrari the slowest to catch on. Ac shops don't want to admit it but when a mad customer comes back with ac discharge the shop is way more likely to stop leack it than tell the customer they need a $300 compressor and labor . Stop leak reacts with air water. No air water in system equals no gelling of stopleak. Rapid depresurizing stopleak comes out as a vapor with the Freon. So no problem with stopleak in the system. There are many faults in a Ferrari system. The dirty secret is that stopleak fixes that with no issues. We used stopleak in Porsches, Audi etc in the days when they also had no clue. In my own 550 I had a slow leak required once per year charge. Stopleak and my system is flawless and cold for 3 years now. As a dyi guy it is my labor so I don't do while you were in there's. Ac is only a few simple components so a major rebuild is no big deal even if the system is fouled. Many parts such as receiver dryer and expansion valve are change as part of quality routine service. Then you got a compressor as a wear item and not much else to foul. So stopleak is not a bad word to me. But john is right IF you can really seal a Ferrari system. I would not use stopleak on a Lexus I know those work as engineered. Ferrari???? Well good luck with that. Let's see if with new parts you aren't back here telling us about recharging it again. My guess see you back here in one year.

 

Carl, many of the A/C websites have DIY tutorials on their sites about "revising" these variable displacement compressors to be the old on/off cycling style due to sticking or other problems affecting the operation of these RCV's (Refrigerant Control Valves). Me, I like the concept of the variable displacement too much and would want to keep it and make it work right, rather than dumbing the compressor down to be the on/off style. I'll grant you that stop leak hasn't been specifically cited as the reason for these valves sticking, but I don't know that I'd want to risk it.

John, I have no experience with the rebuilder you mentioned, however the guy who owns/runs the place in Florida, www.ferraricompressors has been very helpful every time I've contacted him.

There's also a fellow here on FChat Ads who is selling a 550 rebuilt compressor and receiver/dryer combo for around $850, IIRC, and I think that's on an exchange basis. You might think about contacting him.