Like most cars there are common areas that can need attention. Below are some of the maintenance areas that we are often asked about, or are required to repair on the E46 M3, in addition to a normal service routine.
The E46 M3 S54 engine is one of the classic power units, but they can have problems with their big end bearings. There are many theories on the cause of this, from our own to simply overly tight tolerances from the factory. Regardless of the cause the result is the bearings show premature wear. Given the performance and use of these cars it is prudent to replace them where possible.
Replacing the engine bearings should be done with the upmost care and attention, whilst you can just replace the bearings like for like we take the time to make sure every journal is perfectly cleaned, inspected and measured. This ensures we are able to use the correct bearing sizes when installing the new replacements. Each engine will receive its own report and documented bearings sizes.
2003 Model Year M3’s have revised engine rods so we install stronger ARP connecting rod bolts as part of the bearing replacement work.
Given the age and use of some of the E46 M3’s we see they often need to replace the engine mounts, which can fail over time or customers would prefer a preventative performance upgrade. This does not require any additional labour and we carry all the options on the shelf. This includes Powerflex's new upgraded engine mount kits. The work includes a new sump pan gasket, engine oil pump O-ring and an engine oil change and with genuine BMW oil filter. As the bearing replacement requires the front sub-frame to be removed we complete the work with a full wheel alignment setup.
We typically allow 2 days for the work to be completed and customer are welcome to borrow one of our courtesy cars.
2x per car at £135.95 each
The high pressure oil line is known to crack on the joints through vibration which will lead to oil leaks, running issues and can spray oil over the engine bay.
The Hel flexible steel braided hose pipe replaces the original steel pipe and is not effected by the vibrations. It features a heat shield to protect it from the heat generated by the manifold to minimise the rise of future failures taking place.
We highly recommend its installation for both road and track driving. Typically it will take around 1 hour and is more cost effective than the original BMW pipe.
BMW E46 M3 are known to wear issues with their rear differential and currently the only official solution is to replace the whole assembly at significant cost (£3,000+). If the issues are left unattended it can cause serious damage to the rear diff assembly so we would recommend overhauling the diff when it develops signs of a problem. We regularly check the Diff play and condition as part of all our M3 services. Often cars will experience a “clunk” from the back of the car on gear change and when inspected there will be excessive backlash in the diff. This common problem can be solved by replacing the worn bearings and parts within the differential.
Our E46 M3 rear differential overhaul service includes replacing the internal bearings, seals, Diff oil and labour.
It is unfortunate that these great cars suffer from such a fundamental flaw in their design. It is almost certain that every E46 series car will experience cracking of the rear flow and mounting points for the rear subframe.
Having repaired a number of our own cars we are able to offer a service that includes drilling and welding the cracks, installing upgraded reinforcement plates, powdered coated rear sub-frame, re-painting and sealing. While the sub frame is out we shot blast it and apply also replace all of the rear bushes (inc. suspension arms) with upgraded Powerflex bushes and complete the work with our 4 wheel alignment setup.
This comprehensive overhaul and upgrade of the rear of the E46 M3 will insure the car has many more years of fun available.