Hi just bought a fit with 73000 miles and after a week the ac compressor is making terrible noise at idle with the ac on or off. I am wondering how can I diagnose if it is just the ac compressor clutch bearing or if it’s the whole compressor? The ac was blowing hot also or at least warm not sure if it felt like the heat was on but it was warm . Any help on the diagnosis process would be greatly appreciated.

 

Don't know if this will help you but even though this is an old thread it might help others down the road. I have a 2007 Fit Sport MT with 221,000 miles. Until recently the A/C has never been touched and worked fine. Then an occasional rattling sound started coming from the engine. At times it was a noisy metallic clatter. It was not consistent but eventually I figured out from using a mechanics stethoscope that the noise was coming from the A/C compressor. Noise only when A/C was on. I had replaced the A/C clutch coil about a year ago but nothing wrong with the sealed system. I'd put up with the rattling noise for several months and then the coil I'd replaced a year earlier crapped out again. When I removed the clutch pulley I noticed the bearing was noisy and made grinding sounds when I turned it by hand. It's a double row ball bearing and the bearing was discolored meaning it had gotten very hot. That heat probably killed the new coil which is very closeby. It was an NSK 35x55x20 sealed bearing. Honda does not sell the bearing separately, they want a steep price of about $280 for the pulley which includes bearing. I did some research and found a factory original NSK bearing for about $24 on Amazon. I have a hydraulic press so I was able to press out the old bearing which is swedged in and press in the new bearing. When I put the clutch back together I noticed the new bearing was a loose fit on the aluminum nose cone of the compressor. When I say loose, slop was 0.028-.030" . Pretty bad. Hmmmn. What's going on here I wondered? Then I noticed some shiny scoring on the aluminum nose cone and I put two and two together and figured out what happened. The original bearing got grabby and had excess resistance hence causing overheating. Then due to excess heat and friction, it must have started turning on the inner race of the bearing against the much softer aluminum nose cone of the compressor input shaft. I had to buy a new compressor even though the original Sanden compressor was still just fine internally. Compressor is no good if you can't spin it reliably. Honda dealer wanted over $800 for a rebuilt compressor. That's crazy so I bought a new aftermarket one made in China for $135. So far that's working fine and it's been three months. The new compressor came with a clutch and coil so hopefully I'm all set for years to come.

In a situation like yours, I would throw a set of gauges on the car and see what your pressures are. If you get anything in the range of 20-35 psi low and 150-200 high side your compressor should be ok and you need to fix something mechanical like a pulley bearing. Even if you don't have a press, you could save a bundle by buying a new bearing and finding a shop who'll press the old one off and press new bearing on. It's a ten minute job, shouldn't cost that much especially if you have a good relationship with the shop.

 

Yes the thermal switch is built onto the compressor, if the compressor is hard enough to trip the safety thing you have other problems, System may be overcharged, condenser fan not be running, or intermittent. The coil on the fan clutch may be going bad, or it’s worn and needs to be re-shimmed.