1994 E500 auto climate control - heater failure

[larskristian351]

Hello.

When i select warm air on my Auto-climate control, then it blow hot for a while, then it start to blow cold air. When i rev the engine then it start to blow hot again.
And its difficult to get stabil temperatur out the blower. It start to blow cold after a while, like i write above and i rev te engine and the temperature get normale for a minute again.

Can someone help me please?

Greetings from Norway!

Best regards
Lars Kristian

 

[gerryvz]

It sounds to me strongly that your auxiliary water pump is not working, which means that it is not circulating warm coolant through the HVAC system when the car is idling or at low speeds. When you rev the engine, it "activates" the water pump to spin at a higher speed and circulates the coolant through the HVAC system.

The aux water pump is specifically designed to provide heating when the car is idling/standing/at slow speeds.

Mercedes Auxiliary Water Pump - Bosch 0018351364

Mercedes Auxiliary Water Pump - Bosch 0018351364

www.fcpeuro.com

 

[gsxr]

Lars, when driving the car at steady speed (steady RPM above 2000 or so), is the heater output normal? And the cool air is only at idle?

 

[Kyiv]

Still made in Germany. Just received:

 

[Jlaa]

Still made in Germany. Just received:
View attachment 117736

View attachment 117737

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