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  • [Corsa D 2006-2014] Squeal

  • #2
    I know its difficult to diagnose from a video, but is there anyway you can get a video up for us to have a look at?
    Also, what engine/year etc
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    • #3
      Here you go, as you can see the pulleys have stopped but the noise continues for a few seconds
      its a corsa sri,1.4 petrol on a 63 plate

      D7C69B6F 6925 49E1 8944 C0ADCC998522 - YouTube


      • #4!

        I'm stumped! I can't say i've heard that kind of squeak before

        Bugman are you able to shed some light?
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        • #5
          I have now watched your video four times and still not really come up with an answer to your question. It certainly sounds like a rotating squeal, rather than from say, the exhaust system vibrating.
          Do you have this problem at any other time, other than when you turn 'off' the engine?
          The only thing that comes to mind, is the air-con clutch pulley, but to be honest, I can't even imagine that causing the noise.
          Keep us posted on this, it's most intriguing.



          • #6


            • #7
              Only thing I can think of is the aircon compressor clutch .

              The aircon pulley is freewheeling but has a clutch inside that when activated turns the compressor itself. . If the compressor is turning when the engine is stopped the inner clutch would release, and the outer free wheeling pulley will stop with the engine, because of the fan belt. .But if the compressor is still rotating for a few seconds because of its momentum,then so will its clutch.This continued rotation would be hidden inside the cover of the by now stationary outer pulley.

              I hope this makes sense. Its just a possible theory. Is there any change between aircon on and aircon off?


              • #8
                Bugman that makes a lot of sense , the noise is there wether the aircon is on or off



                • #9
                  Do you mean there is a bit of rattling all the time, or does the few seconds 'turning' noise always occurs even when the air con is off. My diagnosis would be better proved if it did not happen when the aircon is off.
                  But its possible if the clutch mechanism is a bit stiff and not always disengaging freely .It might sometimes drag enough to turn the compressor when it should not. This could increase fuel consumption. But if my theory is correct,the clutch does partially disengage because the compressor still turns briefly independent of the fan belt pulley.Its not fully locked. Yet it would apparently have enough drag to turn the compressor,despite a fairly large load (enough to slow the engine tickover) . Maybe my theory is wrong.

                  Things might improve if you are able to access the clutch by removing its protective cover , clean the mechanism and possibly lightly lubricate selective moving parts such as pivot points.
                  As I am not 100% sure of the diagnosis I would hate you to go to unnecessary ,or inadvisable, work or expense without further research or an expert second opinion.

                  With the engine on tickover, and the heater fan on 1 or above you should notice a change in engine note when you switch air con on and off. Running the compressor puts an extra load on the engine. No change but with the aircon still working suggests the compressor is always turning and the clutch may be dragging.

                  Incidentally if your aircon is not actually working because its low on refrigerant, there may not be as much load on the compressor. It might turn quite easily with no more clutch drag needed than can be expected anyway from incidental friction between two parts wizzing round in close proximity.. With low gas pressure the clutch should never properly engage even when the aircon is switched on.. You may always only be getting this incidental friction.
                  Last edited by Bugman; 02-05-2018, 07:47 PM.


                  • #10
                    There is a very slight intermittent squeak when the engine is running but it only makes the loud squeak when you stop the engine , unfortunately it makes the noise when the aircon is both on and off


                    • #11
                      Sorry I did a major edit before I noticed your reply. It might add more info.

                      I should point out again what I have said is only a theory, based on very little experience.

                      On my old clio the clutch mechanism was more exposed and you could see whether the aircon compressor was turning or not.But it was about 10 years ago and I cant remember exactly what you saw. When the car leaked its Freon refrigerant the compressor stopped turning, until it was re charged.

                      Until now I have just assumed the clutch mechanism must be activated by electromagnet, which presumably has a freon pressure over ride switch. I have just checked on line and I was correct, it is activated by an electromagnet although the sites give little detail of the clutch mechanism itself.
                      I think it must have return springs and mechanisms, but I dont know if these fail, or whether they can be serviced, or how. And this may not be the problem.
                      Last edited by Bugman; 03-05-2018, 06:03 AM.


                      • #12
                        Another thought. On this video the compressor pulley appears to run on ball bearings. Presumably it rotates on this bearing regardless of whether its driving the compressor or just freewheeling. When the engine stops the fan belt brings the pulley to an abrupt halt. But could the ball bearings continue to rotate in their race for a few seconds? Not sure it sounds quite right, but a possibility.


                        • #13


                          • #14
                            Ok thanks for the update. Glad you're getting it sorted.


                            • #15
                              did the crank seal cure the problem and did you have an oil leak from the seal