The outside temp gauge on my 97 e320
reads 10 to 20 degrees too high.

On this site, Barrie advised that the
temp sensor and gauge cluster could be
tested on a w124 by replacing the temp
sensor with a 3000 ohm resistor and
observing a 77F temp reading. Can I
use the same procedure to test the
temp sensor and gauge on this w210?

Thanks in advance for any advice.

Darrell

I don't have the spec in front of me. I do know that the sensors are prone to fall out. Just look under the front bumper (you may have to take out the lower panel). You should see the sensor under the bottom on the driver's side in the lower portion of the bumper panel. If it has fallen out, you may have found the problem.

Seldom will a faulty sensor or display result in that small of an "error", with that consistency.

An easier and non-intrusive test is to compare the display temperature against a digital thermometer with a probe ($15). Place the probe as close to the sensor as possible. Be sure to do this comparison when the engine is cool and the front bumper is in a stable temperature environment, out of the sun. Chances are that you'll find the two readings within a degree or so.

Remember that under normal conditions the outside temperature is being taken in relatively close proximity to the radiator, the warmer pavement, exhaust from other vehicles, etc. You need to (mentally) adjust for these influences when comparing your display reading with the "real" outside temperature.

Barrie