Our Cars | Piers’ E46 330i Touring

After a quick weekend break across the most expensive stretch of water in the world to the IOW, summer hols have given me a bit of time to get on with another major job, the dreaded Vanos seals. Like most of the things that I have already done on the wagon, the Vanos seals are another thing that needs sorting because of perished rubber/plastic. The double Vanos system on the M54 engine varies the cams on both the intake and exhaust in order to increase power and torque for any given engine speed and throttle position. After time, the four rubber O-rings on the pistons inside the system harden and perish because of the material they’re made from. A Vanos rebuild centres around changing the old seals and the O-rings are upgraded from Buna rubber to Viton; Viton copes much better with the oil and heat inside the engine.


So all of that sounds simple and it kind of is, except you have to pull apart all of the usual things when working on the M54 engine: the air intake, radiator fan and cabin filter housing and rocker cover. The ’50s Kid on YouTube has a great tutorial on how to do these things. He also has a Vanos rebuild tutorial, which includes the anti-rattle rings (which I don’t need to do… yet!). I have watched the videos of ’50s Kid several times now so was pretty happy with how to do things. I had stockpiled all of the parts to do the job with the replacement seals themselves where from I6 Automotive.


Whilst taking on this job it is a good idea to change the gasket between the block and the Vanos unit and then, whilst the rocker cover is off, all of the gaskets on that. I also decided to change the spark plugs whilst everything was off as it was easier. Six NKGs sorted out the pretty tired-looking Bosch plugs!

Once the system is off it’s fairly straightforward to swap out the seals for new ones. Like everything you just take your time and work in a clean environment! Make sure you have plenty of rags around when you are getting the unit off as there is quite a bit of oil which will come out and happily cover all of your radiator hoses and drive belts – not something you want to happen!


With the seals done it is just a case of getting everything back together again. On start up the engine will sound a bit rough but that is just the system having to refill with oil. I am currently pootling around for 100 miles below 3000 revs to bed things in, so will let you all know next month how things have changed, if at all!

What has happened every time I have done a major job to the engine? You guessed it, a coil pack went down, the engine light went on and the car started running on five cylinders! So I sorted the problem for good and replaced all of the remaining old ones. Apparently if one goes they all start to go, as the next weakest one becomes the weakest link!

I am hoping that now the Vanos seals, spark plugs and coil packs are all new the engine will have a new lease of life and fuel economy will improve that little bit more as well.

Next time I should have changed the fuel filter, as I’m not sure when that was last done. Also the rear suspension will hopefully be back from the powdercoaters!

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