Ok so on all BMWs from this time period, regardless of engine (323, 325, 328, 330, 525, 528, 530, 540, and etc.) the cooling system was known to fail at around 100k miles. Most people who are aware of the problems replace everything ahead of time so that they dont have to deal with it. Most common problems with the cooling system are:
1. water pump seal failure
2. cracked expansion tank
3. failed thermostat
4. leaking hose
Basically, if you replace all of the above, your cooling system will last with no problems for about another 80k miles at least, or about 8 more years. Most people on the BMW forums did this at about 90k miles just to be on the safe side. It's not terribly expensive for a peace of mind, however, if parts 1, 2 fail, you will lose all your coolant and your engine will overheat very quickly. This will cause you to blow your head gasket which is an added headache on top of replacing the violating cooling system component. this is why most people replaced all these parts ahead of time before they actually failed.
A D V E R T I S E M E N T S
Ok so on all BMWs from this time period, regardless of engine (323, 325, 328, 330, 525, 528, 530, 540, and etc.) the cooling system was known to fail at around 100k miles. Most people who are aware of the problems replace everything ahead of time so that they dont have to deal with it. Most common problems with the cooling system are:
1. water pump seal failure
2. cracked expansion tank
3. failed thermostat
4. leaking hose
Basically, if you replace all of the above, your cooling system will last with no problems for about another 80k miles at least, or about 8 more years. Most people on the BMW forums did this at about 90k miles just to be on the safe side. It's not terribly expensive for a peace of mind, however, if parts 1, 2 fail, you will lose all your coolant and your engine will overheat very quickly. This will cause you to blow your head gasket which is an added headache on top of replacing the violating cooling system component. this is why most people replaced all these parts ahead of time before they actually failed.
- mujjuman, Poughkeepsie, NY, US