I've a noise coming from my j reg.BMW. It sounds like a sowing machine or a lollipop stick clicking against bicycle spokes!! It happens when i press the accelerator pedal when driving along but if i feather back the pedal and catch the revs as they fall back the noise stops,only to start up again when i press the pedal down further and so on.Any thoughts on what it could be before i take it to a garage to be checked out?
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I could be waaaaay off track here, but maybe its a "ticking" camshaft, caused by excessive wear?
"ticking camshaft" is a phrase I heard years ago...
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had the car since new.55k on clock. camshaft replaced at 23k didn't remember it making this noise.
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I get a similar noise from the hydraulic tappets on my F Reg 318i with the M40 engine. It comes and goes for the first mile or two after a cold start. It's caused by the oil passages becoming partially blocked on an older or poorly maintained engine. When the oil is thick after a cold start there is insufficient pressure in the hydraulic tappets for them to operate correctly. As the engine warms and the oil thins, enough gets into the tappets for correct operation. Apparently it's not too serious as long as it goes way reasonably quickly but eventually it will cause excessive camshaft wear. To replace the tappets alone can cost around £300 in a garage.
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notlob: can you confirm this - your car is 1989/90 J Reg, i.e 13 years old. So you so do just over 4000 miles a year.
1. How much of this is long runs (say, 100 miles plus) and how much is very short runs (say, 10 miles or less)?
2. If you are using this car so little, are you doing oil changes at 6 months?
3. Camshaft replaced at 23k miles!! ? Why? Could it be the same problem has occured again? Or was the job botched then?
4. Could the noise you describe be due a loose/worn camshaft chain?
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notlob
It appears the noise is related to throttle opening - you indicate that closing the throttle reduces the noise, but opening it again brings the noise back. That makes it less likely to be something like tappets - these would tend to rattle all the time. My thoughts would be a blowing exhaust manifold gasket - these can give a 'ticking' sound.
Regards
John S
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notlob,
Despite the good description you gave, it's very difficult to *visualise* the noise without actually hearing it.
As I'm sure you know, your M40 engine has a timing belt, not a chain, and I wonder if the noise you can hear is the belt slapping under certain speed/load conditions. Perhaps the belt tensioning isn't correct or it needs changing?
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