Question about 1999 Chrysler 300M

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Car is over heating. antifreeze leaks out the top of the reserve.

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You most likely have a bad head gasket. When the gasket goes bad you can have antifreeze mix with the oil or pressure from the cylinder can enter the oil or cooling system.

In your case the gasket has failed between the cylinder and the water jacket. This is allowing the pressure from the cylinder to enter the cooling system and the pressure is exiting via your overflow jug. If you remove your spark plugs you will most likely find one or more that are wet with antifreeze.

Posted on Oct 18, 2013

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Can be caused by many things.
does it leak (overheat) all the time.
does it do it at first start, parked, idling, for 5mi, or 30min.?
or only after engine warmup ,then i drive and only at stop signs
does it overheat moving fast , steady 45mph speed?
there are many tests, all are easy.
first off , it can be bad RAD,thermostat, lost coolant (ignored service) bad water pump, bad RAD CAP.(replace if bad)
or cracked engine bock, cracked head, bad head to block gasket.
to name a few.
if it only fails at stops signs look for RAD tube blockage
i use an IR pyro gun to find these.
there are 3 more tests, ask.

Posted on Oct 16, 2013

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  • _-__-___-_
    _-__-___-_ Oct 18, 2013

    there are many ways to overheat. the best way to find it is to post all symtoms. and even better is to use the leakdown tool and the Exhuast gas in RAD tool. I will not, guess. i do about 10 tests to find this problem. here is jus one test. (did the RAD fan lockulp, when it overheated, or the electric fan(s) turn on.. at over heat? no location stated (alaska) the engine will overheat on all cars, when the fan fails, just sitting idling, after all there is no air flow, so must. The RAD is an air to water heat exchanger. cut air , it dies.

  • _-__-___-_
    _-__-___-_ Oct 18, 2013

    are you running 50/50 % coolant? AF? is the cap good on rad, gasket on it not cracked, so it can hold 14psi pressure? is there oil in the AF (look in rad neck,cold) is there AF inthe engien oil, (milky oil)?

  • _-__-___-_
    _-__-___-_ Oct 18, 2013



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