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Old 08-02-2005, 08:51 AM
Jim H Jim H is offline
Join Date: Aug 2000
Location: Holland, MI
Posts: 1,316
Originally Posted by Paul Feirick
...uphill on I-17 at 75 mph the temperature goes straignt to 115-120C.
This requires a high percentage of the total engine horsepower, which will put a significant percentage of total heat into the radiator.

75mph produces a lot of 'ram air' effect, so I don't think the auxiliary fan adds much to the airflow. Ditto the engine-driven fan. The cooling is determined by the radiator effective area and the water pump flow rate.

My 1992 300D has run hot since I moved to Arizona...
Ambient temperature has an effect, too!

It sounds like it is not overheating, it is just running at the hot end of allowable. Given high ambient temperature and high horsepower requirements, it is to be expected.

By the way, what does the temperature gauge read when you are going downhill? It should drop back to 80-85C...

Best Regards,
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