Preventative maintenance before CPO warranty ends?

12-04-2025

Hi all – I have a 2021 xd40i with ~50k miles under CPO warranty expiring this upcoming spring. It’s going in for service shortly, and I’m thinking about preventative steps I should take before the warranty runs out.

Transfer case: no shuddering or other symptoms, but perhaps worth changing the fluid proactively? Any other steps to take on this front?

A/C evaporator coil: is there anything to do here as a prevention step?

Are there any other common failure areas to consider?

Thanks!

03-25-2026

CPO shouldn’t really factor in here - it won’t cover any preventative maintenance. I just got a 2021 40i with 57k and I have done or am doing everything below between now and 60k.

- Driveline fluids: front/rear diff and transfer case
- Filters: cabin and engine
- Spark plugs
- Serpentine belt and tensioner
- 12v battery (always do this at 5 years)
- Oil and filter to standardize on my own schedule

You may also want to do the brake fluid and coolant depending on when that was done last.

I would also take the vehicle to BMW and have them run their multi-point inspection just in case there’s something wrong that you’re not aware of.

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Preventative maintenance before CPO warranty ends?

Preventative maintenance before CPO warranty ends?