Peugeot 205 1.4 carb - Spasmodic noise from warm engine

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Sun 6 May 2018 10:50
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Andrew-T

Car starts and runs well, battery holds charge. After a few motorway miles musical noise may start, usually with easing off the throttle, coming and going with pedal pressure. Ah, alternator bearing I thought, and a few drops of oil there relieved the symptoms for a while. When the noise returned for a third time I fitted an unused replacement alternator - fine. B*gg*r me if the noise didn't start up again in just the same way yesterday.

Haynes says the belt tension should give 6mm 'slack' on the belt run, which is about what I set. However this seems rather tight to me, so I shall slacken off a bit. But could the noise be something else? Engine has about 100K miles, but was recently overhauled.

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Sun 6 May 2018 11:44
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Peter.N.

If it was a overtight cambelt it would tend to whine all the time. Could possibly be a gearbox or diff whine.

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Sun 6 May 2018 16:28
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Andrew-T

No, it's the external belt which only drives the alternator (2 pulleys, not 3). I've heard the noise from other old 205s and I still think it's the alternator. But I don't think an unused alternator (a refurbed one on the shelf for 4 years) should be doing it ?

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Sun 6 May 2018 17:46
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Sparky Mark
More likely to be a worn belt tensioner. General rule of thumb for me regarding tensioning belts on older cars is at the longest span between pulleys if you have enough slack to rotate the belt 90 degrees that is tight enough to provide drive but not excessive enough to overload bearings on alternator or water pump. Most modern belt assemblies now have pre set tensioners. 205 is a bit old school.
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Sun 6 May 2018 18:38
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Andrew-T

If the noise is from a tensioner it must be from the timing belt, which was renewed 12 to 18 months ago (by the previous owner, I'm not sure of the date). The noise started about 3 months ago, so I don't think it is that. The alternator belt has no tensioner as it's on 2 pulleys only. It needs several miles at 60mph for the noise to start, and that usually happens when I lift off the accelerator. Power-on again usually stops it, but I can just hear it grumbling.

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Mon 7 May 2018 11:26
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Peter.N.

The best way to check is to remove the belt and try it, although if it drives the water pump it could be a problem.

The fact that it only does it when warm could still indicate a gearbox or diff whine. Does it do it continually once its started or does it go off again. Can you post a video of it doing it?

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Mon 7 May 2018 14:52
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Andrew-T

This external belt drives only the alternator. The timing belt is enclosed and will drive everything else. I could easily uncouple the alternator by removing the belt, then follow the procedure below.

Getting a video, or even demonstrating the problem, is tricky as the noise doesn't occur with the car stationary. The usual scenario is for it to drive quietly until several miles have been done at 60+ (3300rpm). The noise may then start if I lift off the throttle gently, and usually stops again on acceleration. It then continues off and on until I return to a lower speed on the A-road, sometimes returning briefly during stop-start through town. By the time I get home it's quiet again.

My hope is that the noise may be caused by an overtight belt. I have slackened it slightly (as suggested above) to see what happens.

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Tue 17 Jul 2018 13:12
Peugeot 205 1.4 carb - Spasmodic noise from warm engine - Andrew-T

If the noise is from a tensioner it must be from the timing belt, which was renewed 12 to 18 months ago (by the previous owner, I'm not sure of the date). The noise started about 3 months ago, so I don't think it is that. It needs several miles at 60mph for the noise to start, and that usually happens when I lift off the accelerator. Power-on again usually stops it, but I can just hear it grumbling.

Update - car failed completely a couple of weeks ago and had to be recovered. Now running again after new cambelt kit fitted, so that diagnosis seems to have been correct - lucky no valves damaged. Time will tell if the problem has gone away ....

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