07 3.0I Coolant Flush?

[1RonRock]

So I am in process of replacing the Radiator Expansion Tank on the Z4. In the process of removing the cracked one for replacement I have drained 1 gallon of coolant. So I went looking for a DIY on the process of flushing the system. Figured it would be a good time to do it anyway. The car has 120K or so on it.

In the research of the coolant flush I read different opinions on weather or not a flush is even necessary. From what I found a flush isn't really as easy as I thought. It seems to require draining the system, filling with garden hose water, letting engine run until warm, cool down, drain, repeat until water drains clear. Sounds like a long messy process.

So I ask is a flush on an 07 N52 Z4 necessary? Or would I be just as well to replace the tank and top it off?

Or even better is there a better, less time consuming/messy way to flush the system?

How much coolant after a flush?

[gpraceman]

Do not use tap water to flush!!!! Use distilled water. You don't want any minerals or contaminants from tap water messing up your cooling system.

If my car had 120K on it, I would certainly do a flush. While coolant is supposed to be a "lifetime" fluid, it does pick up contaminants over time. I do also think that BMW considers lifetime to be 100K miles. You may also want to consider changing out the water pump for one that has a metal impeller, instead of plastic, and the thermostat.

I think on your engine, you have an electric water pump, so no need to run the car between flushes.

I found this DIY guide helpful when I did my flush.

[1RonRock]

Thanks for the link. Good help.

[GeorgeT]

Make sure you use the correct coolant; some coolants will react with others and you will have a mess.

[jclausen]

2007 has the n engine with the electric water pump there is a bleeding procedure that needs to be done. Just drain and fill the cooolant system, it's that simple and use BMW coolant.