This radiator coolant reservoir/expansion tank for E46 M3 is a common failure item as the plastic weakens and cracks, causing coolant leaks. If your E46 M3 has over 80k miles and still has the original expansion tank, we highly recommend replacing it during your next major service.
Show More Show Less
We have found that the expansion tanks should be replaced based on age as well as condition. Expansion tanks seem to have a lifespan of less than six years before they show signs of fatigue and wear. Pre-emptively replacing the expansion tank as part of an overall maintenance plan can prevent you from getting stranded from a sudden failure later on.
Show More Show Less
