450 sl too hot!

Discussion in 'Engine' started by NOMONEYBUTAMERC, Aug 9, 2011.

  1. NOMONEYBUTAMERC

    NOMONEYBUTAMERC MB Enthusiast

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    Went for a spin the other day to Bourton-on-the-Water. Approx 75 miles each way , with a mix of motorway/ a roads. Got a little concerned with high water temperature , particularly on the return trip .( spent 5 hours at Bourton, so plenty of time for it to cool down).About 20 miles from home , the needle was alarmingly close to the red , so decided to pull into services. As it has the original thermo-couple (?) fan , the fan stopped when the engine was switched off. Thought that i may be better off continuing the journey at 50mph rather than chance the engine cooking whilst stationary. The temperature did dip slightly , but rose again on a steep incline about 8 miles from home. Very,very hot by the time i got home. Checked water flow, seems to be pumping ok , no loss of coolant , no binding of brakes, no apparent damage to hoses. Car is only used in summer , and i was wondering if it would be of benefit to replace the fan with an electric one , and what type ? Is it worth removing the thermostat ? Any ( sensible :rolleyes:) ideas please.
     
  2. BTB 500

    BTB 500 MB Club Veteran

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    Is the thermostat opening (water flowing through rad)?

    Maybe flush the radiator / cooling system out. Radiator could be partially blocked.
     
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  3. RaceDiagnostics

    RaceDiagnostics Active Member

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    If all is ok with the thermostat, check that the distributor is tight, if it had move towards retarded the engine will run hot.
     
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  4. OP
    OP
    NOMONEYBUTAMERC

    NOMONEYBUTAMERC MB Enthusiast

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    Thanks. If i advance a couple of degreees do i need to turn dist. clock or anti clockwise? Would electric fan cool better?
     
  5. BTB 500

    BTB 500 MB Club Veteran

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    It shouldn't need an electric fan if everything is working properly.
     
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  6. Stratman

    Stratman MB Enthusiast

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    If it has a viscous coupled fan the fan could be faulty. If the coupling fluid has leaked out (not uncommon) although the fan may appear to rotate it won't have enough power to move meaningful amounts of air.

    If you're feeling adventurous you could try the carrot test. When the fan is rotating with a hot engine it should be able to cleanly slice a carrot. If it can't it needs replacing.
     
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