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Michael Warfield
Michael Warfield, Factory Mercedes-Benz Technician
Category: Mercedes
Satisfied Customers: 3135
Experience:  Mercedes-Benz Master Certified technician
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Have s 78 450 sl small pump that all heater hoses go into is

Customer Question

Have s 78 450 sl small pump that all heater hoses go into is leaking wgat is this part called?
Submitted: 1 year ago.
Category: Mercedes
Expert:  Michael Warfield replied 1 year ago.

Are the hoses leaking coolant? Is the small pump located on the engine or some where near the firewall?

Expert:  Michael Warfield replied 1 year ago.

I think what you are talking about is the auxiliary water pump or coolant recirculation pump. This pump improves coolant flow through the heater core at low rpm.

Expert:  Michael Warfield replied 1 year ago.

Is this what you are talking about?

Expert:  Michael Warfield replied 1 year ago.

There is also the heater core shut off valve or "mono valve".

Expert:  Michael Warfield replied 1 year ago.

I found a clear picture of a 78 model

Expert:  Michael Warfield replied 1 year ago.

The heater servo is circled in red, the auxiliary pump is circled in blue.

Expert:  Michael Warfield replied 1 year ago.

Let me know if you need anything else before you decide to rate me, thanks!

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