Aluminum corrosion on water pump hose connection

[HarryMead]

The spout on the aluminum water pump housing shows white powder under the rubber hose leading to the radiator.  What should be used to remove the white powder and what kind of paint will prevent recurrence?  This corrosion occurs only under the hose connection.  Where the coolant flows, no corrosion at all.  I have seen this on other Mercedes engines.

[waqas]

I've had some success with silicone grease on the metal cooling/heater pipes (between hose and pipe). It should probably work just as well with the aluminium parts.

Keep in mind, the hose needs to be a good fit so nothing can get in-between. A hose clamp is not for tightening the hose ID over the pipe OD, but is there to ensure it does not come off due to pressure.

[HarryMead]

thanks for the advice.  I have yet to drain the cooling system and inspect the hose connections.  I will try to remove the white powder and find some kind of paint to prevent recurrence.  I will report back on degree of success.

[mdsalemi]

thanks for the advice.  I have yet to drain the cooling system and inspect the hose connections.  I will try to remove the white powder and find some kind of paint to prevent recurrence.  I will report back on degree of success.

Harry, forget the paint idea, it won't work.  Any paint under that heat and under those conditions will absolutely, positively not hold, so don't waste your time and money.

Use a good aluminum cleaner, a scrubby pad (non-metallic) and the grease that Waqas mentions.  You can get various kinds of silicone greases, valve greases either online or at a local Grainger.  Dow Corning makes quite a few.  Petroleum based greases might attack the rubber, the synthetics and silicones will work.  Dow 111, Dow 4 or nearly any other will work for what you are trying to do: prevent corrosion on aluminum under the hose.

[Atazman]

Don't know how long it will last, but I used JB Weld on some of the corrosion areas.  I cleaned everything best I could, dabbed JB Weld on, filed/sanded it down, and installed hoses.  4 months now and no seepage.