Hi,

I am wondering the group's opinion on engine reliability for the 2004 525i, which has the M54 engine (more specifically, M54B25).

Specifically, I am wondering about reliability past the 150,000 mile park. I've owned the car since 90,000 miles.

Being 10 years old, the car is not worth much, thus a 'major' breakdown could easily cost more in repair than the current value of the car. I can deal with electronics breaking, but I'm concerned long-term about the engine.

Your thoughts would be very welcome. Thanks!

 

If you keep up with regular engine oil changes and maintain your cooling system, M54 reliability is about as good as it gets without going totally old school and getting an M20 or M30 powered car.

 

agreed. just keep good oil in it.
im finding now at the 160 mark ive been replacing items including, oil seperator, water pump, pulleys, tensioner and now a valve cover gasket.
ive also heard of these motors being known for needing lifters down the road..

 

Not sure I'd put M20 on any durability list unless you're religious about changing the timing belt every 50k. M30? Yes, bulletproof. So much so they built the S38 off it.

We have an X5 with M54 3.0. Running like a champ with 250,000km.

 

I rebuilt the M20 in my E30 at 199,306 miles (built it into a 2.9L stroker). At that mileage, BMWs original cross-hatching marks at the cylinder walls were still visible. I had 0 wear at the top of piston travel. I had a fractured upper compression ring on cylinder 3, and the thing was still making good power before I tore it down.

I also had a 325e that I used as a beater car. Odometer broke at 360K, so who knows how much mileage was really on the motor.

Just like any engine from any manufacturer, they all have specific service points that need to be addressed. Change your timing belt ever 4 years/60K miles, keep your valves adjusted, and change the oil and you'll get 500K out of an M20, maybe more.

M10, M20, M30 - BMW will never top the reliability of those engines.