From the outside these two look exactly the same. However, it looks like the rear one (bet. #3 and #4 cylinders), the temp sender switch, has a smaller "sensor" than the egr one. I may have inadvertently switched them when I took out the head, so I just switched them back.

Thanks,
bigmaq

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2009 R350, now the daily driver
1980 300SD, was the daily driver