Anyone experience this, the last four/five times during the first start of the day I get a loud super high pitch sound lasts for only a second then goes away?

 

my car did that too last week. it sat for about 5 days.. then upon first start i heard a very loud sharp metallic sound for a fraction of a second. i'll start her up this sat and see if the noise comes back. i wonder if it has anything to do with low oil pressure at startup?

 

it is the air pump. Required by emission controls.

 

i never heard this sound befor but if i do now i'll know what it is ,thanks

 

my car did the same on cold start, normally it happens just on the first start up in the day..

it gone away after i took the car to the shop for oil change...

but strangely it comes back a few days after...

 

I agree with the symptoms above, if I run the car fore a few days straight it does not seem to happen. But if it sits then it comes back, never happened within the first 2k mile break in though not sure why. It's a sharp distintive sound metal on metal like someone sticking a metal rod into a fan or grinder. Harsh sound IMO not a normal sound.

My E60 M5 started making a metal clunking/tapping sound on cold start at around 5k miles dismissed as normal by the dealer than got worse louder and longer. It was an oil restriction to the top of the engine at cold start, the supply tube had to be replaced major surgery etc. Hope that's not the case here.

 

Service Manager told me this was the rockers at startup?

 

It's normal. Theories I've heard are dry valve lifters or oil pump priming, and now air pump? I'd love to know the definitive answer.

My car also puffs smoke occasionally at cold start-up. But only occasionally.

 

normal

 

yep, it never happened during the break in on my 3...

nevertheless, last time when i started up the car, the noise wasnt there despite the car been sitting for about a week. what i did was turn the key to the position where all electrical device are on but not the motor, normally i will just give a few secs for the oil to be pumped up before starting the motor, but last time after i turn the key to this position, i got a phone call came in, so the wait was abit longer before i start the motor, and there wasnt any noise at all.

anyway, i will try do the same again today see if this really can eliminate the problem