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#1
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Temp swing 300SD
Refribing a 1984 300SD. Replaced the radiator, thermostat and all rubber hoses, etc.. after a full coolant flush with the engine drain plug . Took four passes until clear water came out.
My question -at at idle up to 45-50MPH the temp guage sits steady at 85C. However on the highway at 65-70MPH the temp gauge is at 90C. (No AC or heat on in both cases) Been two weeks and no change. I had though the faster speed would cool the engine faster ANy thoughts? |
#2
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Where did you get the thermostat? I'd maybe pull it out and test it on the stove. See what temp it's opening at.
Also, maybe try a 'point and shoot' temp gauge to see if its really that hot. HTH, Kat |
#3
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The reported temperatures do not suggest a problem with the thermostat.
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#4
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Thermostat from fastlane here.
I have an IR gun & can get a reading when the MB is at idle in my drive way-but I cannot figure out how to get a reading from the IR gun when the 300SD is traveling 60-70MPH ;-) |
#5
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See if you can get this guy to get the temp from below...
http://www.imdb.com/media/rm1491638528/tt0082971
__________________
mjk '84 300SD 119KMi (Liesl der Diesel) '84 300D 326KMi when the oil left (former parts car) '82 300SD 253KMi (new parts car) |
#6
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Quote:
The only way for the thermostat to open a bit more is for the engine temperature to rise a bit. Many of these engines run all day at 90-95°C. without any ill effects. Chasing this ghost is usually non-productive for most. My '84 decided to run at about 96°C. a few years ago without any obvious culprit. I did change the 'stat with no benefit. The radiator was also changed a couple of years later due to leaks. No change. I suspect the gauge but I'm not chasing it down. |
#7
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I hope you are correct. Not an issue now with the cool weather.
However I am in south Florida and have fears of waht will happen to the engine temps when it is 95F outside and the MB is stuck in traffic with AC on high |
#8
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Quote:
The question is simply how much cooling capacity is being utilized when the gauge reads 90°C? The thermostat may only be 1/2 way open under this condition, providing more than ample margin for those hot days. However, be aware that few older vehicles can manage equilibrium at 95°F. ambients without any airflow and with the a/c on. The engine provides some overhead in this situation by allowing the temperature to climb toward the 120°C. limit. It will likely do so until some airflow is established. Last edited by Brian Carlton; 11-09-2010 at 12:33 AM. |
#9
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120C. Wow. that's impressive.
Last edited by Brian Carlton; 11-09-2010 at 12:33 AM. |
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