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Cooling Fan? Or AC Compressor?

Hey Guys,

I’m revising this thread to reflect some new developments in hopes that others will weigh in.

I’m back with another problem on my '03 Liberty Sport. 98,000 miles.

Lately I’ve been noticing that whenever I have the defroster or AC on, I get a low-pitched, roaring sound coming from the front end of my jeep.

I stopped by the shop today. Diagnosis was that I needed a new fan module. $410 part. The mechanic said that when my AC compressor kicks in, the fan has to rotate at a higher speed. He said there were some busted parts inside the fan, and when it runs at a higher speed, it’s vibrating excessively.

OK, so I decided to get a second opinion. Another guy looked at it, and told me that the fan wasn’t the problem - he said the AC compressor was bad. His reasoning was that when the compressor’s electrical power was disconnected, the noise went away. He said he thought the fan itself was fine.

After that, I went to one more shop. Didn’t tell him about the previous diagnoses, just explained the symptoms. He also said it was the AC compressor - and that it sounded like one of the freon lines was plugged up or something.

I’m surprised about the compressor, because I just had the whole compressor / AC accumulator replaced (and had the lines flushed) less than two years ago. The replacement compressor wasn’t remanufactured - it was new.

I posted a short video clip demonstrating the noise further down in this thread.

So basically at this point, I’m trying to figure out how to move forward. Given the car’s symptoms, which diagnosis do you trust more?

Thanks.

Have you tried a salvage yard?

Called one, they didn’t have it in stock. But I can try others.

I guess my main question is that it seems a little silly to replace the whole thing. Isn’t it possible to take it apart, find the busted part (whether it’s a bearing, motor, or whatever), and just put it back together? I’ve looked around online and it seems like people do sell the individual parts that make up the module.

But I’m not an expert by any means. Just a car owner trying to learn.

You can buy an aftermarket radiator fan motor for less than $100 but if you want factory parts it is serviced as an assembly.

If it’s of any help I just shot a quick video demonstrating the problem. Just curious if you think the fan motor itself is the problem, or whether it’s something different. You can hear the noise really clearly at about 0.40.:

That is alot of noise. Are you at the airport blocking the runway?
The motor shaft bearings typically wear out. Your mechanic can check the motor shaft bearings by holding the fan blade and moving it side to side.

Sometimes plastic fan blades warp from the extended exposure to radiator heat. This can cause vibration and noise. Whether that’s the case with your Jeep I do not know without having car in hand.

A look at the O’Reilly Auto parts site shows a fan motor assembly available for anywhere from approx. 110 to 120ish something dollars, depending upon manufacturer, while the motor alone is about a 100.
It would make more sense to just buy the complete unit and change it out rather than going through the headache of disassembly and repair of the motor; even if parts could be easily found. Odds are not.

Aftermarket fans are about 100 bucks and look robust. I bought one. Installation literally took 5 minutes. Buy the whole thing, shroud and all. It’s a very satifying repair because it’s cheap, easy, and you’ve beaten the dealer out of at least $300.

(post deleted)

The first thing to do is purchase an inexpensive mechanics stethoscope and place the probe on the compressor and on the fan. This will pinpoint which is causing the noise.

Tester

The deleted post (as much as my memory allows) seems that it made reference to the back of the compressor being wet, or oily.
That could point to a faulty compressor seal or improper connection of the hose fittings which in turn could lead to refrigerant oil loss; a compressor killer if there ever was one.

I agree with Tester; use a stethoscope and determine which one it is. Hopefully it’s the fan.

Hi Guys,

Followed your advice and sadly, it was indeed the compressor. Seems pretty strange to me that it would have failed in less than 14,000 miles. It wasn’t a cheap remanufactured compressor - it was a new one made by the Compressorworks company. If I was still living where I’d had this previous compressor installed, I’d go right back to them and complain. Unfortunately, I’ve relocated, so that’s not really an option.

I took it to another independent shop recommended by a friend. He found a ton of metal shavings when he evacuated the system. So I’m having him flush the system out, and change out the condenser, and accumulator…which is exactly what I had done less than two years ago.

Why do you think a new compressor would fail so quickly?

Also, the previous shop where I had the (now bad) compressor installed has the following on my invoice: “As there are many parts to an a/c system we cannot be responsible for parts that may fail in the future.”

That disclaimer kind of ticks me off, but how does it strike the experts here? Is it typical for a shop to have this kind of policy on AC repairs?

Also, based on what I’ve told you, do you think this is simply a matter of bad luck, or poor work on the AC system the first time around?

If the previous shop replaced the accumulator, flushed the system, etc, etc. and the new compressor has now gone south my feeling is that it was caused by one or more of a number of things.

  1. The shop did not do a good job of flushing the system and old debris has taken out the new compressor.

  2. The shop did not add enough, or any, oil to the new compressor.

  3. Per my prior post in regards to your deleted post about the back of the compressor being wet it could be that a fitting was not properly installed, leaking, etc. and it could be said that the wetness is refrigerant oil that was leaking. Any time there is a refrigerant leak some oil will be lost. At some point enough oil will be lost that the compressor will trash itself.

My personalyopinion is that a new compressor, properly installed and with the right amount of oil, should not fail catastrophically after 2 years and that this problem is not bad luck.

Typo. Personaly - personal. Oops. :frowning:

Was the orifice tube replaced when the old compressor was replaced? A clogged orifice tube could cause premature compressor failure.

I don’t see evidence of that on my maintenance records…you could very well be right. I’m having that part replaced this time.

Apparently, In the liberty, the orifice tube is part of a larger line - it’s all one piece and has to be replaced entirely. I wonder if they just assumed that the flush would have taken care of everything before.