Z4 35iS Wastegate/Turbo Failure

[Marky264]

Hi Everyone,

Need some advice, So after 4 Months of owning My '61 Plate Z4 35iS I've since had the Fuel Pump changed due to the Car taking over 7 Seconds of cranking.

After that issue had been rectified I believed I would be trouble free for at least a year. The other morning I started up my car and I could hear an Exhaust Rattle on cold start up, It's very noticeable as I notice any small difference to how the car sounds as It's my daily driver to and from work.

The rattle is coming from the Exhaust and the exhaust sounds a lot louder than It was before in Comfort mode It sounds like a flap is stuck or something as It sounds a lot different now when driving, Louder for sure but not subtle anymore,

The rattle happens when you pull away at slow speeds up to 20 MPH or when you put a tiny amount of pressure on the accelerator pedal and quite frankly sounds awful and that It's an old car about to break to other people.

As I'm understanding the warmer the car part of the exhaust expands thus filling that rattle but I don't want It sounding like this every day,

Any advice on what I should do? I was going to call another BMW Service centre in the morning to get It booked in as I'm sure whatever needs to be done will get done under warranty like the Fuel Pump was.

Just didn't expect to get issues like these 4 Months Into owning it. It's only done 38K Miles so I'm Just getting concerned It could be something more.

I also Read on the AUC Paper work that there was a Sump Leak/Weeping Sump that was replaced and fixed at some point before the car was sold to me by BMW Boston Listers, Could this have a relation to it? The Technician who worked on my car last time for the Fuel Pump told me that he noticed It was still weeping and that at some point to bring It back to have a further look.

I read on similar articles that the 335i had something like this and that a Fix was for BMW to cut off the back box or something along those lines and replace and that it was a Vacuum Actuator issue?

Anyways any advice would be much appreciated!

[Z4monster]

It's a case of 'They all do that , Sir'

All the 35i/iS exhausts have a flap in the RHS pipe which often starts having problems at some point.

Mine was about 18 months old and started rattling on start up and when on gentle throttle inputs. The proper solution is a new exhaust system from BMW, which will probably be OK for a while and then go exactly the same sometime later.
My solution was to do the Golf Tee mod on the flap and permanently disable it. It means the exhaust is permanently louder but only to the same extent as when in Sport mode and at wide open throttle.

I prefer it this way and it stops the rattle too.

I pulled the vacuum pipe off and covered the valve stem with duct tape. Then I replaced the hose and bob's your uncle. All done, no more rattle.

[Marky264]

Thanks for your advice,

It appears the Waste Gate was causing an issue with the vacuum actuator being unable to function correctly due to wear as the Technician has described it. Solution was for BMW to Order a New Turbo to be Installed (Under warranty of course). They also noticed Two of my front shocks were heavily worn/broken seals on both sides and leaking oil which in turn stopped my VDC from correctly functioning something I was unaware of.

I should be getting the Car back tomorrow apparently but we shall see. I've been in a loan 7 Series from Enterprise over this past week as the Car actually broke down (Second Time after the Fuel Pump for from the first time) as I had the following attached image appear on my display and loss of power.

I'm really hoping this is the end of the problems for now as I've only had her for 4 Months and It appears It was poorly prepped before the car was sold to me which I'm really unhappy with as those shocks should have appeared on their checks as a bare minimum. Just assessing where I stand on the car if I get It back and It still isn't fixed properly.

I'd hate to think how much all that work would have cost If It wasn't under warranty...

[Z4M-2006]

Be thankful you have warranty

You have bought a highly complex car,the N54 engine and it’s ancilliaries are troublesome... some more than others .

Along with the EDC suspension which has a tendency to leak, good news it’s getting changed

It sounds like you have been unlucky, but there is plenty more potential problems ahead...
Keep it in warranty

[Beerman]

I wouldn't run an N54 engined car without warranty. A few years back I had my turbos changed under warranty due to the actuators and the bill was something like £3500.

The water pump would been over £1000 at BMW prices too.

The insured BMW warranties are more expensive than they used to be. I was only paying around £350 per year 3 or 4 years ago. It looks like similarly aged cars are now around £700 and usually about double that after the 60,000 mile window.