1993 Mercedes Benz 300e Engine overheating

1993 MERCEDES BENZ 300E
16,700 MILES • 6 CYL • 2WD • AUTOMATIC
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ALPHABET
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My 1993 mercedas 300E 2.8 was doining fine two weeks ago. Now Ive notice the temp. guage creeping close to 120C. I checked coolant it,s ok. I locked the fan clutch still no change. The aux. fans comes on about 100C. I changed the oil still no change. replaced tank cap. When temp. gets close to 120C I turn the heater on the temperature drops to almost normal, I cut the heater off temp. start to rise again. When vehicle is at idle temp. stays close to normal. Do you think it could be an air lock in the system? ... HELP
Sep 27, 2010 at 9:17 PM
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MADMIKE1735
  • ✓ASE Certified Mechanic
  • 951 POSTS
  • ASE Certified Mechanic
sounds like poor circulation of coolant.... when you turn the heat on, obviously hot air should blow out... at this point, it should have more than enough coolant in the system if its making it through the heater core.... i recommend starting with changing the thermostat, as its the most practical, and cheapest right now... let us know if this solves it.
Sep 27, 2010 at 9:25 PM
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