bmw m3 knock when starting then goes away plz help

[MARK-E]

plz guys I need help with my m3 v8 ..on a cold start I hear a knock the she warms up and its goes away..

 

[Nick]

:fencelook:

 

[Nikhil]

M3 and Knock... worst horror story ever told :hammerhead:

 

[MARK-E]

M3 and Knock... worst horror story ever told :hammerhead:

but it only happens when it starts

 

[Fordkoppie]

It could be disastrous or it could simply be the normal vanos rumble on startup.

Does it go away after 1 or 2 seconds, or only after warmed up?

 

[Xack]

plz guys I need help with my m3 v8 ..on a cold start I hear a knock the she warms up and its goes away..

Sounds like the oil struggles to get through the engine when cold, when its heated up it thin enough again.....knock sounds on an //M3...oh gosh, I dare not say it.

 

[Fuzz@tinyNET]

Sent from my iPhone 6+ using Tapatalk

 

[MARK-E]

It could be disastrous or it could simply be the normal vanos rumble on startup.

Does it go away after 1 or 2 seconds, or only after warmed up?

yes it goes away after 20 SECONDS and im shitting myself to start it again in case I do more damage .....

 

[Fordkoppie]

20 seconds is much longer than the required time to get the vanos oil pressure up. So something is definitely wrong.

Could also be hydraulic lifters

 

[AndreasSA]

Mileage?

 

[MARK-E]

Mileage?

90000km

 

[Xack]

Mileage?

90000km

Bang goes the theory

 

[hoosain]

do a bearing change ASAP hopefully no major damage yet

 

[R!Yo]

Have the big end bearings checked, if you haven't changed them already.

 

[AdiS]

I think maybe the best option is to get a knowledgable mechanic to listen to te noise.. Unfortunately it's
One of those things that is too subjective for us to diagnose purely based on your description

 

[///M3 - ZN]

:withStu:

 

[Peejay]

So is it every start that it does this? And is it just in idle?

 

[Lizzard]

If it is cold oil starvation for the initial 20 seconds then why not do this and eliminate it, when getting to the car in the morning and before starting add some oil (only a tiny bit) and then start her up. If she doesn't sound then it is the oilpump or oil pipes in the head that is starving, if it is still making the noise then take it to a mechanic or beter take the mechanic to you. But what will help is if you could find another V8, same car and ask that person to come with his car to you and then listen to the two cars and hear the difference if any.

Hope this helps :sorry:

 

[Beast_Power]

Is it a knocking or loud ticking sound, and how frequently do you use the vehicle ?

Also if you rev the motor a bit does it go away, meaning do you hear it only when it idles ?

 

[Philip Foglar]

I would take it to someone that knows these engines and let them take a listen! And sooner rather than later! Lots of good information and advice here, but it's still speculation based and as AdiS said, it's difficult for us to advise without hearing it ourselves.