300E Coolant Loss

Hello everyone..I posted here earlier this spring regarding my car and some operating issues. Everything is pretty much sound with the cars overall running. THe other day while driving the radiator light came on and the
cars thermastat began to climb up to about 100C. I came home, topped the antifreeze off and drove the next day to find the same thing was happening again. I looked under the car for leaks and can't find any. The oil is clean. And there is no white smoke out of the tail pipe. All help is appreciated- Chuck NJ
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100 degree is about right for yesterday. As long it didn't go past it, I would say it is okay. I'd rather use infrared thermometer to determine the actual temperature of the engine rather than the temperature gauge on old cars.
Those temp gauge do go bad and read erroneous temperature as much as 20 degree.
If your engine blower is blowing strong, then that is fine. With the AC on, if the aux fan comes on... then all is well.
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Tiger --
I have experienced something similar on my 1977 300D. There is no antifreeze reservoir as on newer cars. I have noticed some antifreeze leaks after topping off and driving. Had it pressure tested. It held the pressure, so I have (cautiously -- watching the temp guage) ignored the problem and it went away, i.e., the antifreeze "leak" stopped. My theory is that it was just venting excess antifreeze.
phollings
Tiger wrote:

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You probably had an air bubble... so when it burped, problem solved. I have seen three cases of wrong temperatuer reading at the gauge. All old... and/or have high mileage.
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