How to Read Temp Gauge

[bpossel]

Ok, I admit ignorance… :oops: .

How do I read the temp gauge?  See attached pic.

What are the temperatures at each of the “white squares” on our gauges?  Obviously, the 1st one is 100...

Thanks!
Bob


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bpossel
Memphis, TN.
1971 280SL
1997 E320

[Jonny B]

A good question. I would read the square between 100 and 180 as 140 (split the difference), same for the one between the 180 and 250, the middle square at 215. Obviously the scale is not linear. As this is a mechanical gauge, the marks are there to provide a guide to go by??

Jonny B
1967 250SL Auto

[bpossel]

You'll notice that the 250 mark is "right on" the white box.  To me, this would be 250...  The 180 mark is above the white box.  I wonder....  is the actual 180 temp on the white box, which is just below the 180 marker, or is 180 a straight, horizontal needle directly on the 180 mark???

Other comments?

Bob

bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

I believe the index squares are 20C apart. Same as the Euro.
 The F temp marking are there for US version conversion using the C format spacing.
 40C thru 120C

[A Dalton]

quote:Originally posted by bpossel

You'll notice that the 250 mark is "right on" the white box.  To me, this would be 250...  The 180 mark is above the white box.  I wonder....  is the actual 180 temp on the white box, which is just below the 180 marker, or is 180 a straight, horizontal needle directly on the 180 mark?
Memphis, TN.
1971 280SL
1997 E320

  The 120C  square is 248F
 The 80C mark would be 176F..  so, It looks like they are using C index squares with F temp markers for indication/clarification on US versions.
 My Euros has the same spacing/squares, but in C..

 You will notce that the newer Benz [ like my E320] are still using the C with the 20 degree C spacing, but they do not use F anymore as C is Standard coolant temp indication now...regardless of US version
 So, the 40/60/80/100/120 looks correct..notice the distance increase as temps go up..

[bpossel]

Here's a reply that I rec'd from another 113 friend:
Hi Bob,
my interpretation is as follows:
- hopefully never hit the red box, then you're in trouble.
- the whole instrument is not really calibrated scientifically anyway.
- the original German version of the instrument has the same 5 white boxes. On the German instrument the numbers next to the boxes are 40, 80 and 120 degrees Centigrade. That would mean the not-marked inbetween boxes are 60 and 100 degrees Centigrade.
- when they made the US version, they didn't bother to change the boxes. They appoximated the temperatures in Fahrenheit and put 100, 180 and 250 there, although correctly it should be 104, 176 and 248 - of course nobody would put these figures there.
- therefore, when the needle is over the nearly horizontal box, its 80 degrees Centigrade or 176 degrees F, plus/minus a substantial figure for the limits of the instruments accuracy. If the needle is horizontal, it may be already 184 degrees......

So, in summary, the five boxes are 40, 60, 80, 100, 120 Centigrade.


bpossel
Memphis, TN.
1971 280SL
1997 E320

[A Dalton]

<<So, in summary, the five boxes are 40, 60, 80, 100, 120 Centigrade.
>>


 Correct.. and knowing this, if you are looking for true temp, it is the squares read in C that will give you the most accurate reading.. and I find these gauges to be fairly accurate compared with my test equipment.