Maintenance
BMW M3 E30 Maintenance Notes
M3 Engine
Engine is quite robust. Following hints can make it run even longer:
- Use good oil. I use Mobil1 15W50 oil and replace with OEM BMW filter every 3k miles
- If you track your M3, oil pan baffle is a good investment
- Rear Main seal oil leak is quite common
If Timing chain breaks, prepare to pay and clean out some piston and valve bits. Common improvement is to replace stock tensioner with the one from E36 M3. Also guides wear and are very expensive to replace.
M3 Engine Management
- Check evap valve that it is not leaking into atmosphere. My valve was leaking and his will cause lean mixture.
- Check for vacuum leaks. Intake tube and several fittings to the airbox and throttle body so that they are tight.
- As spark plugs I use NGK DCPR7E. Advantage is that I don't need to have the original, hard to find spark plug tool. Plugs are resistor type since Honda coils require ones with resistors. Similar sparkplugs without resistors are DCP7E.
- As spark plugs I use NGK DCPR7E. Advantage is that I don't need to have the original, hard to find spark plug tool. Plugs are resistor type since Honda coils require ones with resistors. Similar sparkplugs without resistors are DCP7E.
M3 Transmission
Getrag 265 Transmission is also very durable. BMW specifies ATF oil to be used but can make shifting very difficult when cold. I use Redline MTL oil.
Common failures are:
- Output shaft gasket
- “Buzzing” shifter
M3 Differential
Differential is a limited slip type and is very strong. Some owners have replaced the rear cover from M-Coupe which can improve cooling.
M3 Cooling & Heating
Some owners have experienced head gasket failures, but with proper care cooling is adequate.
Heater core is one of the typical failures and there is one recall to prevent it exploding on your feet. Core itself is very easy to replace, app 30mins.
Thermostat can also break. Mine broke and stuck open and after that the engine didn’t warm up properly.
M3 Electrical
Relays: I had problems with unloader relays. Symptoms were that heater fan stopped working suddenly and relays inside fuse box were hot. Replaced with new ones from dealer and problem was solved. If your relayes are original ones, my recommendation is to replace all of them at once.
Fuses: It is common for Fuse #10 to burn if reverse light switch cable is not routed correctly.
M3 Brakes
Brakes are very good. ABS system can be quite tricky to fix. My car had several problems:
- ABS Light didn’t come on at all when key was in ACC. Somebody removed the bulb...
- Reversed front sensors. Symptom was that just before coming to stop brake pedal was very hard and brakes disappeared for a moment. ABS light didn’t illuminate
- Over voltage relay. There is a small silver relay above drivers feet and inside the relay is a fusible link. You can open the relay and replace the link with 8A small fuse.
- Cut cable to passenger side sensor. Symptom was that ABS light turned on after car reached 25mph and ABS was off.
M3 Steering
Steering rack: It is common for high mileage racks to start leaking fluid past the gaskets. Mine started leaking and fix was very easy: I installed a strong magnet into the fluid reservoir. In 2 weeks leak was gone.
Charles Wilson
Posted at 2010-12-07 22:36:06
M-3 steering; WHY WOULD A STRONG MAGNET HAVE ANY EFFECT ON THE P/S FLUID LEAKAGE? THANKS
Bemari
Posted at 2010-12-08 01:07:35
Hi Charles,
Magnet actually collects all metal particles from the power steering fluid.