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Corsa 1.7 CDTi SRi screeching/scraping noise when starting

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  • [Corsa D] Corsa 1.7 CDTi SRi screeching/scraping noise when starting

    Hi Peeps,

    I'm having a problem where I get this screeching/scraping noise (see video below) when starting my Corsa, mainly on cold starts. I believe it might be something to do with the starter motor as it sounds similar to that kind of start up noise. I have checked the fan belt and it's not rubbing against anything.

    The car drives fine during the noise and after it stops.

    Any help with determining what the problem is or just agreeing with the above will be much appreciated.

    Thanks in advance

    Anton

  • #2
    Is it the bearings in the Idler pulley perhaps? does it go when you rev the car at all?
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    • #3
      Thanks for the reply Michael

      It does tend to go away quicker when you rev the car/start driving but it also goes away after about 10 seconds by itself, while driving for the first few mins you kind of hear it happening now and again but really quiet nothing like the video of course this is all based mostly on a cold start. I started it again the now and drove it after about 5 hours parked and didn't appear to make that noise, overnight usually does it.

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      • #4
        I'd be looking at replacing the Idler Pulley or the tensioner if I'm honest
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        • #5
          Welcome to the Forum.

          A strange sound indeed.
          Pretty sure that it isn't from the starter motor though, as I could only hear it way after the starter had done its job.
          It could be, as suggested, the belt tensioner (idler) pulley - but then it goes away after a few seconds.
          A long piece of dowel (or even a long screwdriver) placed on the various housings near the moving parts (take care not to touch moving parts with it) and the other end placed in your ear may help to locate the sound, but you would need someone to start the engine for you before the noise goes away.
          Other moving parts include the alternator, coolant pump (water pump) and air con pulley.
          One though is that when you have started the engine, the battery voltage is reduced somewhat, resulting in the alternator working overtime to make up the lost voltage. When the alternator works hard, it puts extra load on the drive belt. If the belt and/or pulleys are worn (or the belt is not tight) this extra load can cause the belt to slip, producing a noise - this is normally a 'squealing' noise rather than what you appear to have but who knows it could be the cause.
          You could try leaving the head lights switched 'on' for three or four minutes before you start the engine, this will pull the battery voltage down further, and if the belt IS the culprit, you should hear the noise for longer after the engine starts.
          You could also slip the belt off and see if the noise is still there when you start the engine. (NOTE: It isn't possible to completely remove the belt without lifting the engine and removing the drivers side engine mount)
          Is there any signs of contamination on the belt or pulleys?

          Regards

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          • #6
            Thanks for your answer Michael and thanks for the reply Walksall, a few points to consider

            I will have a look and listen around the belt area.

            Also! I did drive it again and it made the noise that was only an hour sitting also it made it the noise while I started reversing so I imagine sometime between 1st/neutral and into reverse which was also the loud noise you get when you first start it so the condition of only hearing it on a cold/cold-ish start is somewhat out the window.

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            • #7
              Noises are my favourite part of car ownership
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              • #8
                Excuse my ignorance of this engine. But is that sheet metal shielding over the air filter original? Could it be causing resonance? Try putting your hand on it while someone else starts the car to see if that suppresses the noise at all.

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                • #9
                  Now that you have mentioned hearing the noise whilst you were reversing, I have had another listen to it and am now wondering if the noise is perhaps from the clutch release bearing. That being at the other end of the engine, between the engine and gearbox.

                  Regards

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                  • #10
                    Hey guys

                    Bugman Thanks for the input but I've had the shield off and still makes the sound.

                    walksall The noise is I'm sure is coming from the pulleys/belt area I noticed also when I switch the AC/fan on it prelongs the noise at start up which would coinside with the pulleys. I'm trying to release the tensioner but it doesnt seem to budge I noted you said I have to remove the side mount to remove the belt but the mount is above the belt not through it so In my head you can remove it but is there another reason to remove it?

                    I've watched some videos i cant seem to figure what way to push it any ideas? I've included a picture of what I'm sure is the tensioner. Maybe I'll try again from underneath the car.

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                    • #11
                      The 1.7 diesel is made by Isuzu, so maybe the belt can be removed without an engine mount getting in the way. The reason for removing it is if the noise goes away you can tell if the noise originate in one of the belt driven ancillaries, such as alternator or aircon pump , or caused by the engine. You can then also try turning the ancillaries by hand to see if they seem excessively stiff or rough, rattling or loose etc.

                      The noise didnt sound like fan belt squeal, but the because it gets worse when the air con is switched on it might be. If the drive belt is loose, or very slippery and shiney it can squeal on start up. This is because things the belt drives such as alternator and aircon compressor have their own in built reluctance to start rotating (inertia). A correctly adjusted belt will force them to rotate at the same speed as the engine immediately. If the belt is slipping the things may be slower to get up to speed and the belt slips and squeals on the pulleys until they equalise speeds.

                      If the aircon is off only the pulley of the compressor turns, not the whole compressor. Switching aircon on releases an electric clutch that makes the whole compressor turn, which is a heavier load to get up to speed. Or it might indicate that the noise originates in the compressor clutch mechanism

                      Before removing the drive belt you could try sprinkling the belt with some talcum powder (ordinary bathroom stuff) This temporarily improves its grip on the pulleys (or possibly lubricates it) so it doesnt squeal as much) . If this stops the noise you know the belt is slipping. Either tension it up, or if its very shiney or has any sign of wear, micro cracking etc its better to replace it. If you cant get a belt that is definitely slipping to stop slipping, you may need to look again at the ancillaries.
                      Last edited by Bugman; 12-08-2018, 06:24 AM.

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                      • #12
                        Yes, it is only with the petrol engines that the engine mount is 'within' the belt. However, access to the tensioner on the Diesel engine is best gained by removing the drivers side road wheel and inner wing cover.

                        SAFETY NOTE: Use axle stands (one will suffice, leaving the passenger side wheel in place) DO NOT work under the car when it is supported only by a jack.

                        With the road wheel and inner wing cover removed, you get a clear view of the tensioner.
                        It is all well and good taking the tension off of the belt, but you need to be able to keep it off during the belt removal/replacement.
                        As well as a spanner for the tensioner centre bolt, you will need a steel pin, bolt or drill bit (from memory, about 4mm diameter)
                        Turn the CENTRE bolt of the tensioner pulley CLOCKWISE (against a quite strong spring) - this will release the tension from the belt.
                        Slip the pin, bolt or drill into the hole in the tensioner body above the centre bolt (you may well have to vary the position of the of the centre bolt by turning it more (or less) in order that the pin, bolt or drill will slide all of the way in.
                        Once in place, the pin, bolt or drill will keep the tension off of the belt.
                        The belt can now easily be slipped off (Before removing, take a photograph or make a note of the belt run around the pulleys.)

                        Taking into consideration the work in removing/replacing the road wheel etc, it might be a good idea to buy a new belt and tensioner and replace the old ones regardless of condition.

                        When the belt is fitted, make sure that it engages with ALL of the grooves on the various pulleys before removing the pin, bolt or drill.

                        As Bugman says above, try turning the various pulleys by hand (obviously you can't turn the crankshaft pulley) - If the bearings of the pulleys feel 'rough' then extra work is obviously required..
                        Also make sure that there is no contamination (oil) on the pulleys before fitting the new belt.

                        Regards

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                        • #13
                          Hello,

                          Thanks for the great info guys, very much appreciated. I was able to get the belt off, my friend was able to do it from walksall via the wheel arch (axle stands were used and chocks, it took a lot of force to move it he said but... happy days anyway.

                          The belt itself is new, it got replaced I'm pretty sure when I bought the car not long ago as it was pretty clean with no cracks and appeared to be very tight when on. Also the tensioner looks new well newer than the rest of the parts.

                          With the belt off the noise is gone! So checked all the pulleys the idler, tensioner aren't too loose and they're not to stiff either. The A/C and pump appeared to be okay far as I can tell. The only one that stood out was the alternator that made a squeaking noise when turned anti-clockwise. With the belt put back on the noise came back not as bad as it was, my friend and I are pretty sure the noise is coming from the bottom area so the crank or the alternator.

                          Now I think the noise is coming more from the crank area but I could be wrong so either the alternator pulley is the culprit or something to do with the crank perhaps with the belt it applies too much tension?

                          Bugman Since the A/C is at the top I'm sure I can rule that out being the source of the noise as I can get a good ear to that with it on but it obviously puts pressure on something as it does appear to provoke whatever in to making (more) noise.

                          I have attached a video of the noise whiles it's running from below and included another video linked below of a sweep of the area.


                          This is going to be either something stupid and easy or down right expensive

                          If you have any other thoughts... Thanks again.
                           

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                          • #14
                            As you say, that idler does look new. However, depending upon the quality of the new idler, it COULD still be the culprit.

                            Than bottom (crankshaft) pulley is held on to its hub by the four bolts in your photograph, the hub in turn is held onto the crankshaft by that single central bolt.
                            If those four bolts are tight and the pulley isn't loose on the hub or catching on anything, the problem is unlikely to be in that area.
                            DO NOT remove the centre bolt that holds the hub to the crankshaft, or you will have to reset the valve timing.
                            If there is no oil leaking from around the hub, then there is no point in removing it anyway.

                            If the sound from the alternator was very 'light' when you turned it ant-clockwise, it was probably from the brushes, which are 'used' to it turning in the clockwise direction only. On the other hand, if it was a louder noise, it is possible that the alternator bearing(s) are the cause - especially when the extra load is applied by the tensioned belt.

                            Remember what I said about checking for the noise with a long piece of dowel or long screwdriver (better still, a mechanics stethoscope if you have one.) By using this method, you could pinpoint the problem, for example - the front or rear alternator bearing.

                            Regards

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                            • #15
                              Hey Guys,

                              I bought a mechanics stethoscope walksall and wouldn't you know I'm having a hard time replicating the noise as it seems to have stopped making the noise or it's very quiet... typical

                              I will keep an "ear" on it and update at the end of the week.

                              Thanks for all your help so far guys.

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