Auxiliary heater circulation pump /05,e320, cdi

[dorje]

I have a failing pump, works only intermittently, the circulation pump from Mercedes is $285, the Bosh pump $85. Any reason not to go with the Bosh?

[engatwork]

No

[BillGrissom]

No, indeed Mercedes doesn't make that pump but just stamps their brand on it. I replaced the aux water pump on my 1984 and 1985 with a section of 5/8" silicone heater hose. I haven't seen a U.S. car with such a silly water pump, so figured not needed and can only cause problems. One of mine started slinging coolant from the shaft. They could also jam to hinder coolant flow or even cause a cabin fire since the extra current burns up the push-button switch box (M-B neglected to fuse it, but you can add one). Where I live in CA, the heater gets the cabin extra toasty, though I've never driven it up to Lake Tahoe in winter.