what kind of preventive maintenance to do?
 

just got a 525i on thursday with 133k miles

ive done engine oil change and power steering fluid change. i intend to change spark plugs sometime in the next couple of weeks. i have no real records of what was maintained. should i do transmission or differential fluid changes, brake fluid, coolant, waterpump too?

http://imgur.com/qNzwCxB

i'd change all fluids and filters, except the coolant, until you get a better idea of its history or wait till something breaks. or maybe down the road when needed along with another repair.

Establish a known base line and sleep better at night. All fluids are a good starting point and then expand.

Drive belts, break system, spark plugs, air filter, suspension components, cooling system and other normal wear items are also good items to review.

Good luck and remember a good PM schedule goes a long way to not finding yourself along the side of the road scratching your head....

+1 for cooling system components - Water pump, thermostat, hoses, expansion tank, vent tube.

All of the other PM is important, but nothing can leave you at the side of the road, or seriously damage an expensive engine faster than overheating.

Use good quality parts also. Don't do like I did and buy off-brand components. I thought I would save a few bucks and bought Beck Arnley thermostat and water pump. The thermostat lasted a week and the water pump exactly two years. Junk! If you are doing the work yourself like I do you are already saving so much money on labor that it is worth buying the best parts so you don't have to do it over soon.

+1

Keep an eye on your injectors , just replaced all of mine at 62k theyall seem to leak at some point

Injectors leaking is not a common problem [on E60]. Note OP has 525. It's not direct injection or turbo; simple naturally aspirated engine.

thanks for all the insight guys