After starting from cold I hear a loud buzzing noise, a bit like a dry ball bearing race. No noise from a hot start and just a bit from a warm start. It only lasts for a minute or so and goes if I rev the engine. It's difficult to pinpoint as it seems to be 'all over' the engine and doesn't last long. I've replaced the water pump, cam belt and alternator. I know that the carb flexible mounting is split, couldn't be that - could it?
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Could it be a sticking starter motor pinion, i.e. not coming out of engagement with the flywheel ring gear until the engine is revved? This would possibly be more likely with a cold engine as any oily crud between the pinion and its shaft would be thicker.
If it *is* the pinion, the oil needs flushing out and then just a *touch* of very thin oil put on the shaft (others may say "leave it dry" and I wouldn't argue with that).
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Dizzy, Thanks for suggestion, the starter is noisy but works OK.
The buzz I hear is something like a worn / noisy alternator bearing.
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Had a Passat that made a similar noise for first 2-3 minutes, it started at 80 000, sold it at 170 000 still made noise every morning, worse on cold mornings, never did it after it got warm. Sounded just like a dry bearing.
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BeetleFreak, thanks for the 'comforting' reply.
The last couple of warmish mornings it's been quiet !
Am going to replace the perished flexible spacer on the carb hoping that there is some sort of vibration when on full (auto choke) causing the noise.
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Might be the timing belt scraping on the inside of its cover.
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Common problem on VW's it is the oil pressure relief valve chattering on its seat. Once the oil is warm it doesnt have to work so hard so is less noisy. What grade oil do you use?
Andrew
Happiness is a T70 at full chat!
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AM (tune up)
Noted your reply to my post and similar reply to another post. I changed the oil from ordinary 20 - 50 to 5 - 30 semi - synthetic. This reduced the noise and it didn't last so long.
But - the hydraulic tappets became noisier. Have since changed back to 20 - 50 and back to square one. Proves your diagnosis OK.
You say that you've heard loads of similar engines, not terminal then ?
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No, not terminal but,personally speaking I would (at your next oil change) change to a semi synthetic 10w/40 or 15w/40 (Texaco Havoline is my choice) after flushing. 20w/50 is too heavy and the cause of your original trouble. If the tappets are noisy try a dose of Forte Top End Treatment which will a) clean out the hydraulic lifters and, b) clean the oil pressure relief valve.
Andrew
Simplicate and add lightness!
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