ED wrote:

<snip>

 Mark, if you really had excess air flowing through your radiators the coolant would drop more than 4 Deg F.  In fact, the more air flow the more coolant Delta T you would drop through the radiator. 

<snip>

 

That's exactly what I HAD thought, until I was told that the air could pass through too fast and not pick up as much heat.  This didn't make sense to me.  Maybe I wasn't listening closely and missed the point altogether (wouldn't be the first time). 

 

What I DO know is that the air is flowing faster through the water radiator than the oil radiator.  (I'm not sure I have the ASI's hooked up correctly, but they're both hooked up the same).  I have a pitot behind each radiator hooked up to two separate ASI's.  In slow cruise, say 125-130 kts, the water radiator ASI will read about 110knts and the oil ASI will read about 90 kts.  The way it was behaving before I opened up the exit, it appeared that the air from the water radiator was trying to exit backwards through the oil inlet.  I say this because of how high the oil temps were reading.  I enlarged the cowl exit, and both the water and oil temps dropped significantly. 

 

The ASI's are referencing the static port for these readings; should they be referencing cowl or cabin pressure instead?  Airspeeds readings seem awfully high to me. 

 

Mark

(Going to the airport today to recalibrate temp sensors)