Skip the auto shop - Our mechanics make house calls

Q: BMW 330d Rattling-Hissing Sound from exhaust side

asked by on

I have a 2004 bmw 330d automatic (steptronic) with an M57N (M57TU30D) engine and is making a rattling, squeaky-hissing sound from the exhaust side of the engine on idle. Started off a a minor faint sound but is now louder and sounds like a worn out clutch/ DMF. Sound is not coming out of the engine itself but outside towards the tranny. When the problem was getting worse, I was getting a yellow oil light after switching off engine and responded by topping up with a pint of oil but the light still comes on. Checking the dipstick would give me a normal level so I am no longer topping oil with the fear of adding too much oil. I also have acceleration and power issues when going uphill and have to resort to changing to manual shifting so that I can get enough power. I am inclined to think it could be vacuum-related but want second opinion and confirmation. Thanks in advance
My car has an automatic transmission.

Hey there. Thanks for writing in today about the rattling / hissing sound coming from your 2004 BMW. I experienced a similar issue and it was in fact a vacuum leak. However, there are several other symptoms of a vacuum leak that you should consider before diving in and buying replacement parts.

Typically, the hissing sound will be accompanied by a lack of power on acceleration, loss of fuel economy and in some cases, an engine misfire. If your car is experiencing any of the following, then I’d say the issue is definitely vacuum-related.

A worn out clutch will also produce several driving / performance loss issues, as well as commonly produce a rotten egg smell. If you need additional help looking at the problem, contact one of our local ASE certified mechanics, to pinpoint the cause of the hissing noise and make the appropriate repair.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Hi i have a toyata camry 5 speed i was driving home and heard a pop noise the a squish noise i was wondering what it could be.

Hello. We are happy to help you out. The squishing noise will be best investigated first hand. It may be something with the hydraulics power steering but it would need to be heard first hand to help ID it. The...

Q: The engine loses power after a longer drive

It is possible that your fuel pump would be getting weak. Often times if the fuel level is run low many times, this can cause the fuel pump to overheat. If the fuel pump overheats, this can cause it...

Q: Car won't start after it sits for like an hour

Hi There, It sounds like you may have a faulty fuel pump or fuel pressure regulator that may be allowing the fuel pressure to decrease when the car sits for a period of time. This will happen a bit naturally,...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...