Quote:
Originally Posted by gareth12468
The passenger side is completely closed and the drive side has a small opening on the top left on my 28i.....
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I checked the parts drawings and only the 35i uses an open grill on the passenger side.
The 20d and 30d both use an oil to water heat exchanger to cool the engine oil. Both diesels use the same type of heat exchanger.
The 28i uses a different heat exchanger which is also an oil to water design.
Therefore the 20d, 30d and 28i do not have a oil cooler in the front fender and have "dummy" (closed) grills. Oil temperature is regulated by the engine's water temperature controls.
The 35i uses a remote-mounted oil to air heat exchanger/oil cooler/radiator behind the open grill. That engine also has a oil thermostat that regulates the oil temperature to around 118 Deg. C (245 deg. F), by bypassing the oil cooler when the oil is cold.
The small opening in the left side grill on all models is for the outside air temperature probe. The vehicle must be moving so air is pushed through the small triangular opening for the probe to measure the correct outside air temperature.
The non-functional "NACA" ducts on the plastic bottom covers just inside of the rear doors are still a mystery!