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Old 12-16-2016, 02:45 AM   #1
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Join Date: Dec 2009
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My Ride: E46 M3 & F30 328i
Mandatory Maintenance for you E46 M3 - VANOS, Rod Bearing, and more

Hey everyone. Of course you know there are some big maintenance items for the E46 like the subframe reinforcement, rod bearing, and VANOS but there are a few others as well.

I wanted to put together a list of issues here so it's kind of a one-stop for all things maintenance. I've done pretty much all of these services and wanted to share to the new owners and prospective owners what to expect maintenance wise. So here we go.

Full article here: Ultimate E46 M3 Maintenance Guide & Schedule
  1. Rod Bearing - Excess heat and friction will cause your S54 rod bearings to wear overtime and at about 100k miles you should really look into replacing your rod bearings. There are some additives you can add to limit the wear, but it’s only short term. We did a full write up on treating your engine with Liqui Moly MoS2 with oil sample tests in case you’re curious. In the long run, you want to replace. BMW did create a service action recall to fix this premature issue, but still only short term.
  2. VANOS - There are multiple issues associated with the S54 VANOS unit. VANOS solenoid solder connection disconnects, cam bolts become lose and snap inside the engine, worn down oil pump disc, VANOS hub tabs break and gets tossed into the engine, VANOS piston seal o-ring deteriorates, and chain guide wears down. If you’re having timing issues or hear abnormal ticking coming from the solenoid, you definitely want to consider doing a VANOS overhaul. Some get lucky, but when the metal hub tab breaks off it’ll most likely go into your engine causing major damage.
  3. VANOS high pressure oil line - The S54 VANOS oil line creates up to 1,200 psi in the feed line and the neck area closest to the banjo bolt on the solenoid tends to crack or burst. The VANOS high pressure oil is used to maintain responsive and accurate camshaft adjustments. Failure in this line can do serious damage to your engine.
  4. Subframe reinforcement - The rear mounting points for the subframe can rip out in the sheet metal caused by excessive torsion load from the differential to the chassis. We’ve literally seen a chassis split in half!
  5. CPV - The CPV has an o-ring that tends to flatten and harden over time because of excessive heat which causes a leak in the line. The valve is located behind the exhaust manifolds which makes it a must-replace job if you’re taking out the headers for whatever reason.
  6. Radiator - The OEM radiator has plastic end tanks which are prone to crack caused by high-low temperatures. Coolant temperatures can reach up to 207 degrees under normal operating conditions and quite possibly higher during track days. Plastic expands in heat and contracts in cooler conditions so it’s just a matter of time until your OEM end tanks leak!
  7. Radiator hose - The OEM coolant/radiator hose gets brittle and cracks overtime leading to leaks. Just like the radiator issue above, hot-cold temperatures will prematurely wear out the OEM material. If you’re upgrading your radiator to all aluminum, you might as well spend the extra $80 to upgrade your hose kit.
  8. Differential bolts - Excessive torsion load may cause stock differential bolts to snap. Even when you accelerate and decelerate, the drivetrain load causes force and adds stress on the differential bolts. Now, go out to the track where you put the car in a more severe environment, you might want to really consider replacing bolts. $12 for a pair is worth it.
  9. Rear shock mounts (RSM) - There have been many reports on M3Forum on the rear shock mounts blowing out of the washer and causing a bit of damage to the shocks. If you hear squeaking, rattling, or clunking it may be a sign that the RSM is going bad. Monitor around 60,000 miles.
  10. Rear trail arm bushings (RTAB) - Premature wear of OEM bushing can result in poor handling, excessive tire wear, and alignment issues. In some cases, members on M3Forum have reported premature bushing wear at ~40,000 miles of daily driving.
  11. Front shock tower reinforcement plate - When using aftermarket camber plates, the front strut tower may began to deform or crack when driving in “poor road conditions” due to uneven distribution of pressure.
  12. Rear spring perch reinforcement plate - The aluminum cast construction of the lower arm, only on the E46, may cause the spring perch to deform or crack. Similar to the strut tower reinforcement, the uneven load from an aftermarket spring perch may cause improper seating thus damaging the suspension. This applies if you have after market height adjusters.

Shoutout to Obioban for the information he put together in his thread that guided my servicing.

Follow my build on

Last edited by androofoo; 12-16-2016 at 02:47 AM.
androofoo is offline   Reply With Quote

maintenance, rod bearing, subframe, vanos

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