Which coolant

Discussion in 'Engine' started by steve333, Oct 17, 2011.

  1. steve333

    steve333 Hardcore MB Enthusiast

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    On checking my fluid levels yesterday noticed the coolant was a little low & needs topping up(checked all hoses etc for leaks & all ok).Checked the handbook & no specific coolant/part number is mentioned so can anyone tell me which one to buy(2008 cls 500)?
     
  2. Will

    Will MB Club Veteran

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    How much are we talking? If it's just a tiny bit (few hundred ml) I'd top it up with some de-ionised water.

    It's usually a 50:50 mix of antifreeze/water from factory, say 10L approx in the system, so you're not likely to be diluting it sufficiently to worry. I think you can get away with upto a 25% concentration of antifreeze in the coolant, 50:50 goes right down to an exceptionally low freeze point IIRC.

    Will
     
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    steve333

    steve333 Hardcore MB Enthusiast

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    Thanks for the reply Will looks to be around a pint(think the expansion bottle cap was slightly loose & the coolant lost when it became hot),so any coolant from a motor spares shop should be ok or is there a specific mb one?
     
  4. Will

    Will MB Club Veteran

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    1 pint, 500ml approx - that's only around 5% of the cooling system capacity.

    Just top up with some de-ionised water. I've got plenty spare here in Walton if you need some :)

    Will
     
    Last edited: Oct 17, 2011
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    steve333

    steve333 Hardcore MB Enthusiast

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    Got some in the garage,thanks very much for the offer though:thumb:
     
  6. Will

    Will MB Club Veteran

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    Have a look in your owner's book, I think MB coolant at a 50% dilution goes down to something like -35/40c, even a 25% dilution would probably be plenty for our climate - so a few hundred ml of water in the system would be fine - better than mixing coolant IMHO anyway :)
     
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    steve333

    steve333 Hardcore MB Enthusiast

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    Thanks again Will.
     
  8. grober

    grober MB Club Veteran

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    Is it blue or orange in colour. If its orange its extended life. I would top up with a 50/50 mix of antifreeze/water using the appropriate MB antifreeze. Antifreeze also has anti corrosion properties which would be diluted slightly by the addition of water alone. The corrosion inhibitors will already be depleted slightly due to the age of the coolant which will be 3 years old + on a factory fill. On an all alloy block V8 why risk a problem for a few quid? Your MB dealer or specialist will advise a suitable antifreeze compatible with what you have already onboard.
     
    Last edited: Oct 17, 2011
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  9. Will

    Will MB Club Veteran

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    I agree with you in principal Grober, but if we're talking a few hundred ml in a (10L?) cooling system, and most antifreeze/coolant additives are designed to run at a maximum concentration of about 50:50, I don't forsee a problem topping up such a tiny amount with de-ionised water :)

    At the end of the day, 50:50 in a 10L system, even say 500ml (1 pint) approx would equate to a 2.5% difference in water vs. antifreeze.

    (9.5 litres at 50:50, so 4.75 of antifreeze solution, + 5.25 of water once topped up)

    I'd much rather do that than potentially mixing coolant types :dk:

    Most antifreeze I have seen cites varying dilutions from 25-50% approx, so 47.5% antifreeze/anti-corrosion additive would be more than plenty IMHO especially for the UK's climate :)

    I think water quality would be of greater concern than a 2.5% antifreeze dilution tolerence. There's got to be more than 5% remaining water in the system when they replace coolant anyway :eek:

    Personally - I would top up with de-ionised water for now, ensure there is no leaks and then replace the coolant at the next specified interval :thumb:

    IMHO of course :cool:
     
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  10. horgantrevor

    horgantrevor Hardcore MB Enthusiast

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    its probably yellow antifreeze long life
     
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    steve333

    steve333 Hardcore MB Enthusiast

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    Quick update,the coolant was blue in colour so bought some comma blue antifreeze/coolant for the purpose of topping up what had been lost through the loose cap on the expansion bottle,mixed it 50/50 with distiled water(1ltr in total)which brought the level back to max-thanks for all the help:thumb:
     
  12. sl300 ireland

    sl300 ireland Hardcore MB Enthusiast

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    would putting to much coolant vs water be bad ? say 2 litres coolant then topping up with water?
     
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    steve333

    steve333 Hardcore MB Enthusiast

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    Best to check the owners handbook,mine said 50/50.
     
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