My N54 335i Cost Me £3k In The First Week

It was a hot day when I bought the car, and although I'd tested the windows worked on the test drive, I'd driven mostly with the windows up, muting exterior sounds. Ironically, this was something I'd praised the car for, being lovely and quiet whilst cruising.

On the way home, however, I wound the window down. Whenever I let off the gas I heard a really annoying fast paced clicking noise, rather ruining the purr of the straight six's exhaust note.

I didn't think much more of it for a couple of days, then curiosity got the better of me and I started Googling it.

Rather quickly I'd diagnosed the noise as the dreaded 335i N54 turbo waste gate rattle. This post on bmwforums.info tells you everything you need to know to diagnose the problem and the cause of it.

The video below, by helpinghand996, shows what's actually happening when the waste gate fails.

And this video by Alex21usaMARK2 shows a comparison between a healthy car and one with waste gate failure.

My heart sank - to quote James May, "Oh cock".

I knew this meant big money to repair, so I set about gathering quotes. Most people live with the rattle, but to me, having a car that sounds so good ruined by the noise of the waste gates was not an option. Inevitably, the turbos would wear and pack up anyway, causing further damage.

I investigated doing the job myself, but wrote that idea off when I read you'd need to set aside at least 12 hours and is not for the faint of heart. However, should you want to go for it, this guide on e90post.com is supremely helpful.

The amount of work also ruled out having the turbos reconditioned, as I'd not be able to get them out myself. For those interested I was quoted "from £180 up to a maximum of £321 each, depending on the condition" by Turbo Solutions.

Next on the list was to source the turbos myself and pay an indi to replace them. I got a quote from AET Turbos for "£410+VAT each" and Turbo Solutions for "£625+VAT each". Clearly, the price can vary wildly.

I have an inherent distrust of every trades person, rightly or wrongly, to do a job to the standard I would if I did it myself. So, picking an indi to work on my new pride and joy was tricky. After reading a number of praising reviews I settled on Auto Technik in Lutterworth. I called them and got a quote, which was more expensive than sourcing the turbos myself, but not so much that the hassle of doing so was worth it.

When I dropped the car off I also mentioned that my cold start was a bit iffy and told them to investigate.

I got the call the next day to tell me that the High Pressure Fuel Pump (HPFP) needs replacing and the Low Pressure Fuel Sensor too. Yep, the other common faults on the E92 335i. Unlike for our American cousins, in the UK, BMW didn't extend the warranty and there were no recalls. Bother.

The total job would come in at just over £2,900, how's that for a first week of ownership? Bottom lip now properly dragging on the floor I told them to carry out the work. Meanwhile, I worked out how the hell I was going to afford it.

From what I can tell they did a good job, the rattle is gone, the cold starts are slightly better and they didn't scratch or damage anything. I was annoyed they changed a few other bits like the air filter without asking me, I would have up-rated to a performance panel filter, and also a vacuum line had been swapped out with a green hose?! All the others are black, my OCD does not approve.

Lesson well and truly learnt, research common problems prior to buying a car and thoroughly test the car for those problems. I had done some research, but evidently not enough, it was also curious that I didn't hear the problem with the windows down or whilst running the engine prior to getting in. I can only chalk it up to experience.

To make sure I never forget the lesson learnt, I bought myself a commemorative turbo key-ring. Fingers crossed the future is a little bit brighter...

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