[cbarlow]

I have a 2013 335 xDrive with 102K miles and just got it paid off. It's in excellent physical and operating condition and I'd like to keep it (at least) another 3-5 years and for it to last and perform the way a 335 should.

Is there any powertrain (or other) long-term or preventative maintenance that would be recommended?

I've been religious about oil changes, had the spark plugs done at 60K as called for, and had the valve cover gasket done (under warranty) around 83K because it was showing signs of seepage.

For example, is there any kind of advised transmission service? I once asked my dealer who told me no, that once the seals started leaking that's when they'd recommend action. That doesn't sit well with me.

What about the changing the fluid in the transfer case, walnut blasting the intake valves, or anything else? Now that the car is paid off, I want to start planning and budgeting for whatever is necessary to keep the powertrain working like new.

There have been 2 cases - one a month ago and another about 18 months ago - where the car displayed a "drivetrain malfunction" message on the screen. I wasn't driving the car myself either time but am told it happened when they (i.e. my finance the first time and my brother the most recent time) "got on it". After the most recent occurrence I used my BimmerLink app to review the error codes and found the following...

COMBUSTION MISFIRE, MULTIPLE CYLINDERS: DETECTED
COMBUSTION MISFIRE, CYLINDER 4: DETECTED
COMBUSTION MISFIRE, CYLINDER 1: DETECTED
COMBUSTION MISFIRE, MULTIPLE CYLINDERS: INJECTION IS SWITCHED OFF
COMBUSTION MISFIRE, CYLINDER 1: INJECTION IS SWITCHED OFF
COMBUSTION MISFIRE, CYLINDER 4: INJECTION IS SWITCHED OFF
COMBUSTION MISFIRE, CYLINDER 6: DETECTED
COMBUSTION MISFIRE, CYLINDER 6: INJECTION IS SWITCHED OFF
IGNITION, CYLINDER 4: BURNING TIME TOO SHORT

But the car has been driving fine and the only thing I notice is a slight hesitation or "studder" once in a while when it downshifts to accelerate.

Appreciate the input!

[F32Fleet]

Ignition coils are 120k miles.

You could change the ATF and transfer case fluid.

[cfm56d7b]

Is the charge pipe still OEM or did you have a chance to replace it? If not - I suggest to replace it with Evolution Racewerks charge pipe.

What are the exact codes for misfire messages mentioned earlier?

At 100K miles, changing the transmission fluid would be recommended. This procedure also requires changing both filter and the pan.

[Charles B]

I have the same car as you with 120,000 miles, and this year I've done the following.
New front control arms
Spark plugs
Water pump and thermostat
Belts and tensioner
Carbon cleaning the intake valves
Coolant flush and fill
Transmission fluid and filter
Differential oil change front and back
Transfer case oil change
Aluminum Charge pipe

Everything here is well within the reach of DIY.

At 150k I'll do the transmission fluid dump and fill, the transfer case again, and the fuel pump in the tank.

[cbarlow]

Originally Posted by cfm56d7b

what are the exact codes for misfire messages mentioned earlier?

140010 combustion misfire, multiple cylinders: Detected
140410 combustion misfire, cylinder 4: Detected
140110 combustion misfire, cylinder 1: Detected
140001 combustion misfire, multiple cylinders: Injection is switched off
140101 combustion misfire, cylinder 1: Injection is switched off
140401 combustion misfire, cylinder 4: Injection is switched off
140610 combustion misfire, cylinder 6: Detected
140601 combustion misfire, cylinder 6: Injection is switched off
150402 ignition, cylinder 4: Burning time too short

[BMWILUVU]

The coils are old at this point and I would change the plugs again together all in one and then monitor for misfires.

[cfm56d7b]

Originally Posted by Charles B

I have the same car as you with 120,000 miles, and this year I've done the following.
New front control arms
Spark plugs
Water pump and thermostat
Belts and tensioner
Carbon cleaning the intake valves
Coolant flush and fill
Transmission fluid and filter
Differential oil change front and back
Transfer case oil change
Aluminum Charge pipe

Everything here is well within the reach of DIY.

At 150k I'll do the transmission fluid dump and fill, the transfer case again, and the fuel pump in the tank.

Excellent list - glad to see OEM charge pipe replaced. Which one did you select?

[Charles B]

Originally Posted by cfm56d7b

Excellent list - glad to see OEM charge pipe replaced. Which one did you select?

I went with Burger Tuning. Price was $199 and it's works great.

[M Smurf]

https://www.dslreports.com/r0/downlo...e%20v03.13.pdf