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Roger, BMW Master Tech
Category: BMW
Satisfied Customers: 5895
Experience:  10 yrs. experience as BMW Master Technician, shop foreman and dealer.
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I have a 2000 BMW z3 1895cc I have had a squealing noise when

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I have a 2000 BMW z3 1895cc I have had a squealing noise when the engine gets hot. I have replaced clutch thrust bearing fan belt still happening. I have found now that there is is a tremedous build up of pressure in the engine and when I can eventually (very high pressure) prise the oil cap a little the noise stops. (It also stops if I accelerate when i am driving)
Cheers John

Hello John,


My name is XXXXX XXXXX I will do my best to help you with this.

Can you provide me with the last seven digits of the VIN number?

Customer: replied 4 years ago.



Hello John,


Thank you for the VIN. It was helpful as it enabled me to look up the parts listing for you.

When a BMW fails like this with high crankcase vacuum it is due to the crankcase vent valve failing. You will need to replace this valve and associated hoses to correct the excessive vacuum. When this occurs you often get the noise you are describing. The best test is to try and open the filler cap and you find it is under excessive vacuum.

Here is the parts listing for you:

Components 1 and 3.

I hope this is helpful. Please provide a positive rating for my help today as this is the only way I receive credit for helping. I wish you the best with your repairs.

Kind Regards,


Roger and other BMW Specialists are ready to help you
Customer: replied 4 years ago.

Thank you will try this



Excellent :)

This is a very common failure I have seen on all BMW engines.

Best wishes with your repairs! Please remember to rate me once satisfied with my help.

Kind Regards,