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Discussion Starter #1
When I start my M5 COLD, there´s a knocking sound from the engine, I think it´s from one of the pistons... It doesn´t sound when the engine runs "free", but when it´s at load, it does. The sound disappears after apprx. 30 sec of running time, when the engine starts to get heaten up.

Question, HOW bad is this...? Is my M5 knockin on heavens door? Or can it last for a long time, without repairing this? My guess is that one cylinder is a bit oval, and that the piston moves from "side to side" in it, when its cold and "small", compared to when its hot, correct?

//Worried M5-owner. :confused:
 

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morson1 said:
When I start my M5 COLD, there´s a knocking sound from the engine, I think it´s from one of the pistons... It doesn´t sound when the engine runs "free", but when it´s at load, it does. The sound disappears after apprx. 30 sec of running time, when the engine starts to get heaten up.

Question, HOW bad is this...? Is my M5 knockin on heavens door? Or can it last for a long time, without repairing this? My guess is that one cylinder is a bit oval, and that the piston moves from "side to side" in it, when its cold and "small", compared to when its hot, correct?

//Worried M5-owner. :confused:
How many miles does your car have, and have you been doing the regular servicing like valve clearances?
 

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Discussion Starter #3
Hollis said:
How many miles does your car have, and have you been doing the regular servicing like valve clearances?
180000km... I´ve recently bought the car, but I know that the valveadjustment isn´t done. But the sound isn´t coming from the cams if thats what you mean?
 

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Hi Morson1

If it only happens from Start Up for 20-30seconds until engine is warm - it is probably the exhaust/air valve thingy opening. Apparently it's a system BMW used on the M5 to meet the emissions laws?????

I didn't know about it when I bought mine and it scared the sh*t out of me the day after I got it home.

Regards
Yangi
 

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Discussion Starter #5
Yangi said:
Hi Morson1

If it only happens from Start Up for 20-30seconds until engine is warm - it is probably the exhaust/air valve thingy opening. Apparently it's a system BMW used on the M5 to meet the emissions laws?????

I didn't know about it when I bought mine and it scared the sh*t out of me the day after I got it home.

Regards
Yangi
Nono, its not that, that´s a different sound... I wish it WAS that... =)
 
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