weird noise at start up when engine is cold.

[BRGcoopahS]

The car has been making a weird mechanical grinding/whirring noise at start up in the morning. It only happens when the car is very cold. Could it be the starter?

[danewilson77]

Starter or pulley's?

Sent from Williamsburg, VA USA

[drfreeman]

I also have the weird cold start noise, it is louder when giving some gas during cold start. The noise is exactly the same in this video. Can anyone help me to diagnose this noise ? I have changed DISA valve 40K ago and with new pulley and belt. And I did VANO seal at few years ago. My car is exactly 100K now. Thanks. https://youtu.be/Qsf36Mjt2I0?list=FLRorES1BUJksBcK6y5P8wGQ

[ELCID86]

Yikes. That does sound bad. Were the tensioners, pulleys, etc. replaced?

[drfreeman]

Yes, new pulley tensioners, new DISA. The noise is louder when increase rpm but it completely gone after the car is warmed. No lost power or noise when driving.

[justinwilson77]

Does your car have a mechanical fan clutch? I had a similar noise and the problem, after replacing all of the same parts you have, ended up being a bad fan clutch. Also, it could be the water pump, depending on what else you have done to the car.

[drfreeman]

Does your car have a mechanical fan clutch? I had a similar noise and the problem, after replacing all of the same parts you have, ended up being a bad fan clutch. Also, it could be the water pump, depending on what else you have done to the car.

Does ZHP has mechanical fan clutch ? Water pump is fine, just changed new upper and lower hose with pressure check.

[justinwilson77]

do you have a manual or automatic? Auto transmission zhps have a mechanical fan clutch, manual transmission zhpz do not.

[Just_George]

How long does the noise last? You said the noise quits when things warm up....the Secondary Air Pump can make noise when it goes bad (and they do) It's only active for a short time after startup, so wondering if the time-frame matches what you're experiencing and if that might be worth looking into.

[drfreeman]

do you have a manual or automatic? Auto transmission zhps have a mechanical fan clutch, manual transmission zhpz do not.
Mine is manual, so I guess it is not fit into this case.

[drfreeman]

How long does the noise last? You said the noise quits when things warm up....the Secondary Air Pump can make noise when it goes bad (and they do) It's only active for a short time after startup, so wondering if the time-frame matches what you're experiencing and if that might be worth looking into.

It has happened a while already. Yes, the noise will disappear after the engine is warm. No noise and no lost of power during driving. The 2nd air pump noise is like a duck honk sound, doesn't it ?

[danewilson77]

Exactly what pulleys and tensioners were replaced?

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[drfreeman]

I remembered I replaced the all pulley half year ago. I am not sure about tensioner. Does tensioner can make that noise ? Someone suggested the oil pump issue.

[slater]

How long does the noise last? You said the noise quits when things warm up....the Secondary Air Pump can make noise when it goes bad (and they do) It's only active for a short time after startup, so wondering if the time-frame matches what you're experiencing and if that might be worth looking into.

you can actually monitor the activity of the SAI system in PASoft, so that might help determine the issue - if the noise goes away after the SAI system deactivates...

however the noise does sound very mechanical.

[drfreeman]

you can actually monitor the activity of the SAI system in PASoft, so that might help determine the issue - if the noise goes away after the SAI system deactivates...

however the noise does sound very mechanical.
Sorry but what is SAI system and how to get the PAsoft ?

[Karl Lazlo]

Sorry but what is SAI system and how to get the PAsoft ?

Secondary Air Injection.

[drfreeman]

Hey guys, It is very interesting that after I changed all 6 plugs and ignition coils, the noise is gone during the cold start. I test it everyday morning without that noise. In case anybody have the same problem, try to change the plugs and coils. Thanks for all the response.

[BMWCurves]

Thanks for following up and I'm glad you solved your issue.