H2

I just replaced my thermostat and noticed some "white crusty" buildup. Not a lot but I'd like to get dissolve this stuff throughout my cooling system without clogging up my radiator. Any suggestions that won't eat the aluminum away? Thanks!

Harvey

dr bob

H--

No real good options for that stuff. Mineral deposits require that you use something that has a pH that will cause problems with the aluminum block and radiator. In general, there is more at risk with radiator and engine block damage than there is just leaving some deposits in there. Using caustic chems in the engine means that you risk weakeing the aluminum block and heads in critical places, like where the head gasket sits.

Sometimes a mineral film, as opposed to your "white crusty buildup", will come off with your new coolant charge. Plan on changing the coolant again in the fall before winter storage, and see how much of the film has moved into solution in the coolant.

Too many owners decide that they don't need to maintain their coolng systems because they don't drive the cars much. Huh? Still need to replace coolant and use distilled water in there even if you never drive it. Looks like you may be a victim of this thinking.

H2

Dr. Bob,

You almost always have great solutions and good news! But not quite what I was looking for this time.

I'll put in primo coolant and change again in the fall after some summer running and see what happens. Thanks, sincerely, for the heads up. In my old Chevy, we'd "boil" the heck out of them with cautic stuff.

The deposits aren't large that I can tell...but any buildup is more than I want. Again, thank you.

Harvey

Ben

My Mercedes service manual recommends to make a 10% citric acid solution to use as a cleaner for the cooling system.
It says to flush the coolant, run the solution for 15 mins, then perform another thorough
flush to remove the debris.
I cant imagine doing this on the 928 will do any harm if Mercedes recommend to do it in their aluminium engines.

ZEUS+

Calcium buildup is the hardest to remove. Sometimes flushing with water several times is effective. A safe acid free flushing agent is also good.
http://www.barsproducts.com/product.cfm?id=9

Ben

Lol, I should probably state that my Mercedes service manual was written 22 years ago. I'm sure there must be a modern equivilent of citric acid for cleaning cooling systems.

Shark Attack

I wonder if something like oxyclean would work.

Brad W

What about CLR calcium lime and rust remover? Any thoughts on this ?

Daniel Dudley

White vinegar.

Bill Ball

Do a final flush and fill with distilled water. This is probably calcium phosphate from the water when someone neglected to used distilled water in a locale that has hard tap water.