Radiator Flush
 

What material is the best to flush a radiator and attempt to remove mineral scale. Years ago when the radiators were all metal you could soak is a caustic bath but with all the plastic on this radiator it may not be prudent.

Removed the radiator to exchange the M42 engine.

I want also to flush the replacement engine before putting in car. I removed the thermostat and water pump and found a some mineral scale especially on the water pump. Both will be replaced after flushing.

One option is to use white vinegar but open to suggestions.

That's a good question that I don't have an answer to. Have you tried to Google it?

New radiators are cheap enough as it is. You could pick up a Behr which the same as OEM for about $140. Since the factory radiators tend to go at about 140k-150k miles, might be a good idea to replace it anyway.

Thank You for your suggestion but I believe the reason people ask questions on this forum rather than just using Google is to get opinions of people who have the same type car/equipment and the answer hopefully would be more specific and relative.

White vinegar is a good idea for a safe flush I think. Also good for cleaning records!

Tap water / white vinegar/ tap water/ distilled water then finally refill with 50-50 BMW coolant (the blue stuff) and distilled water.

If you refill it with tap water and coolant, it will scale up again. Tap water is where the minerals come from to cause the scale...

Thanks Jim. I will use Distilled and the BMW blue. In fact I plan to do the same on my 535is.

Good man.

People don't realise how bad tap water can be. Obviously it varies depending on the source; however you want zero minerals in the water if you can, and you can with cheap and easy to find (check your supermarket!) distilled water.

Sold for clothes irons for the same reason- minerals in the water can/will stain your shirts when ironing...

There are a few desent radiator flushes on the market. I believe prestone makes the most common one you can go the the parts store and pick up. Flushing radiators has however become almost a thing of the past. Most new cars are highly voltage sensitive and one should never consider putting tap water in as in the days or yore. I know this means little after you have build up. Whatever flush you use could in the end cause more headaches you will be knocking loose large chunks of deposits that most likly will block the radiaor or cause already weak seals to fail. Bmw's seem to have a frail cooling system as it is, if it were me I would overhaul the system while I had it apart, i.e. replace the water pump, the cooling connectors, the hoses and radiator.