Ive got a 2003 Ranger Edge with the 3.0 V6 in it. And its been great since I first bought it last July. However Ive run into a issue, Im not sure if its somthing serious or somthing that should just be shrugged off. My probulm is this. I live in Texas so during the summer it gets pretty hot here. And when I start my truck I like to turn the A/C on Max to allow the cab to cool down before I go anywere. For instance...I'll start my truck without the A/C on then as soon as I switch the dial to A/C or Max A/C there is a sudden very quick split second grinding noise that comes from under the hood. But like I say it goes just as fast as it comes and it never makes the noise while im driving down the road, Even if its 100+ degrees outside and im running my A/C full blast I never have an issue with it until I first turn it on. What could this be? Its important to me that my A/C do not go out in this truck. My last truck an older F-150 lost A/C midway threw owning it and it made driving it anywere during the summer misrable. I really dont want to have to go threw that all over again with my Newer Ranger. Any help is apprecatied!

 

If it's actually grinding then it's probably the first sign of the ac clutch going out. It's not that hard to replace but a lot of shops want a fortune for it. I've had to replace them on two of my trucks up here in Lubbock in the last year and the cheapest price I could find just for the clutch was 65 bucks. It's ridiculous but much much cheaper than a tow bill and the repair at a garage when it goes out altogether.

It's also possible that you have an idler or tensioner bearing going out too that you hear when the compressor loads up but I doubt it. Here in the dry and dusty Western side of Texas that is common but I don't know about your area. The clutch is still most likely.

Look at the clutch for signs of melted rubber isolators on the face of it and really scored up surfaces between the clutch face and the plate. If it looks bad then just replace it.

 

Thanks for the reply and I live in Lubbock myself!

 

I know exactly the noise you are talking about and it can be rather maddening to actually diagnose. I cringe when I hear this complaint from a customer.

It's called compressor"slugging". It can can lead to excessive wear or damage to the compressor in extreme cases.
If it only happens occasionally it's not an issue. Slugging can happen occasionally on any AC system depending on temperature, pressures, humidity, planetary alignment, phase of the moon...
If it happens almost every time you start the vehicle, it is an issue.

Slugging on startup is most often caused by a slightly overcharged system or too much oil in the system, causing liquid to pool in the compressor after shutdown. Liquids don't compress so the compressor knocks for a split second until the liquid is cleared.
If this is the cause, flushing the system, replacing the dryer and adding the correct amount of oil and refrigerant will eliminate the noise.

Problem is, the only way to know if this is or isn't the cause is to flush and fill the system to known proper levels. It works in about 70% of the cases I've seen.
The fun begins when you have done this and the slugging persists.
It's the same problem from a now unknown cause. No matter how much is explained to the customer beforehand, they still often feel as if I'm purposly taking their money for a repair that didn't fix the problem.
Sometimes rerouting lines slightly or insulating certain areas of lines will fix it, sometimes adding a suction filter to alter the internal oil/refrigerant flow will fix it. The list of "possible" fixes is long. There have been vehicles that I've personally never been able to fully cure of this issue.

Late 90's and newer full size trucks (lots of slugging complaints) had the PCM programmed to engage the compressor during engine crank to eliminate the noise. It didn't actually eliminate the cause of the slugging, just the rattle on system startup. The compressor was cleared already by the time it was engaged with the engine running.

Good Luck.