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Old 01-22-2009, 06:24 PM
tangofox007 tangofox007 is offline
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Join Date: Sep 2004
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Quote:
Originally Posted by MBNRA View Post
Normally that is the case, but these cars need an Auxilliary water pump to maintaijn a consistent temp of coolant going to the heater core. At higher speeds in my 1983, the coolant seems to bypass the heater core on the freeway without the Aux pump kicking in. Actually, this might be your problem too, an Auxilliary water pump failure.
In theory, an aux pump failure would cause exactly the opposite symptoms. Its purpose is to improve coolant flow at low rpm. The water pump needs little help at higher rpm.
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