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Old 05-23-2012, 12:20 AM
optimizer optimizer is offline
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Join Date: Oct 2008
Posts: 83
So with the overheating issue... I did some tests this afternoon..

Before turning on the car, I checked the fan:
- Turning it by hand, it would turn max 1/4 before coming to a stop. According to other posts, this seems to be functioning normally

I ran the car in idle for a few minutes to check some basics:
- Fan was turning (counter-clock-wise if looking head on at the car, which seems like it's in the right direction). However, from the front of the radiator, the intake airflow felt minimal - I held up a piece of paper and it didn't seem to stick to the grill of the aux fans. From the rear, the airflow felt like it was going outward radially, not outward to the rear. Since the fan was rotating in the correct direction given the way the blades were oriented, I assume this is normal.
- Pipe from the engine to thermostat and from thermostat to top of radiator both got warm at relatively the same rate
- Pipe from thermostat to bottom of radiator stayed cool

At normal operating temperature (about 85C), engine stayed at that temp for a while, at least about 10 minutes. Here's what happened:
- Pipe from thermostat to bottom of radiator warmed up, but not sure if that was because of the ambient engine bay temperature rising

I turned on the A/C to high, here's what happened:
- Neither of the aux fans turned on, I believe one is supposed to?
- Engine got up to about 95C and stayed there for a while
- With the A/C on, I revved the engine a bit and the engine temp started rising to 100C... then 105C, then slightly above 105C, the aux fans kicked in and the engine temp went down within a minute to about 85C again
- Airflow through the radiator with the aux fans on was very strong, way stronger than with just the main fan

I also didn't notice any change in the coolant level in the reservoir tank throughout everything, and I would have expected to see a dip... is that the correct functionality?
1993 300CE
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