Coolant colour

Discussion in 'Parts, Maintenance & Servicing' started by dozypillock, Jan 21, 2017.

  1. dozypillock

    dozypillock Hardcore MB Enthusiast

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    Went to change the thermostat today, as temp was only getting to around 60 in this cold weather.
    Coolant that came out appeared to be green in colour.
    Looked at local suppliers for fresh antifreeze only to discover that they all seemed to stock only blue or red.
    Assumed Mercedes probably has "special" antifreeze so rang merc in Brighton, to be told "they only use blue, and any blue antifreeze will be fine"
    What is the difference in colours, and how did mine appear green?
    Baffled.....
    Neil
     
  2. markjay

    markjay MB Club Veteran

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    The original MB coolant is long life (15 years). If topping up, use original MB.

    It works, too..... I replaced the thermostat on my 10 years old car (still with its original coolant) an there was no sediment at all on the old thermostat or inside the housing - quite impressed.
     
  3. markjay

    markjay MB Club Veteran

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    Incidentally, it's possible to replace the thermostat with no coolant loss.

    Carefully syphon-out all the coolant from the expansion bottle before removing the old thermostat, then pour it all back in once the new thermostat has been fitted
     
  4. RichardF

    RichardF Hardcore MB Enthusiast

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    It's probably G48
    file:///C:/Users/richard/Downloads/11871%20(2).pdf

    Colour is confusing, it's only a dye.
    But rough rule of thumb.

    Blue from your local shop tends to be 2 yr stuff
    G48 blue/green is 3 yr
    Red tends to be 5 yr

    Don't mix 5 yr with the others it'll coagulate and block your cooling system. Be careful of what people in motor factors tell you.

    I was in a well known national factors the other day.

    Customer; Which antifreeze do I need for a top up?
    Counter assistant; I've got blue or red
    Customer; What's the difference?
    Counter assistant; Blue's 2 yr the red's 5yr
    Customer; Okay I'll have the 2 yr stuff, I'm not keeping the car that long.
     
  5. OP
    OP
    dozypillock

    dozypillock Hardcore MB Enthusiast

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    It is probably about half blue and half green in there now.
    I think I will drain the whole system properly when it gets a bit warmer and refill with all the same stuff.
    Incidentally, Mercedes of brighton (parts dept) told me there is no such thing as green, despite me saying mine was.
    I seem to recall that the last time it would have had any fluid added was probably when it was in John Haynes (local indie) having the gearbox issues sorted.

    Neil
     
  6. WDB124066

    WDB124066 MB Club Veteran

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    Run with what MB says is correct. You wont have any problems and the stuff is cheap enough.
     
  7. CabrioDave

    CabrioDave Hardcore MB Enthusiast

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    Colour seems to depend on the brand - of the two Comma brand antifreezes used by Halfords, the one which meets the Mercedes spec is the G48 ... and that's green!
     
  8. brucemillar

    brucemillar MB Club Veteran

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    I would suggest that you go with:

    a) What is in the book.
    b) What MB recommend.

    It is not simply a matter of colour choice, length of protection etc.

    Pink - Usually OAT can be corrosive to some engines and MUST not be used (in those engines)
    Green - As above has chemicals that some engine components do not like.

    OAT, in Most Japanese engines is NOT recommended as it corrodes the seals and hose connectors. It does this fairly rapidly, so do not think "I wont have the car that long".

    Never mix as that just gives you a complete unknown and can/does lead to other issues (sludging and the like)

    They all cost about the same. So it is a two minute check, either in the book, or a call to MB to check.

    ;^)
     
    Last edited: Jan 22, 2017
  9. Will

    Will MB Club Veteran

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    How much coolant did you lose? Even on a really cold winter in the U.K we don't require the default 50:50 dilution. If you've only lost a few hundred mls or something I'd probably top up with soft water and run it until the next coolant change is due. The cooling system has quite a large capacity and even say 0.5L of water isn't going to significantly change the dilution ratio to make any difference.

    Probably safer than mixing antifreeze if you're not sure what's in there too :)
     
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  10. hotrodder

    hotrodder Hardcore MB Enthusiast

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    Coolant colour is meaningless. As said, it's just a dye and while there are some conventions there aren't any standards about what flavour should be what colour

    Buy coolant from MB and if it's labelled as meeting mb325.0 it'll be G48 these days and dyed blue... http://www.worldpac.com/tagged/MBZ_ANTIFREEZE_G48.pdf Some years back it would've been yellowish and probably G05
    Other brands of G48 are more commonly dyed greeny-blues or bluey-greens
    Regardless of colour G48 is a HOAT coolant, the 2-ethylhexanoic acid (aka 2-EHA)* mentioned in the msds is one of the OAT corrosion inhibitors used in various other flavours of coolant. G48 also contains silicates which are one of the common IAT inhibitiors hence the H for hybrid
    As said g48 is typically stated to have a 3 year service life according to the people who actually make the stuff like BASF Glysantin

    While there are probably various other corrosion inhibitor differences silicates are the main one that's missing from 'straight' OAT coolants favoured by a bunch of other car manufacturers who typically prefer cambelts over chains... AIUI silicates are particularly good at protecting aluminium in areas subject to cavitation like water pumps. With cambelts the waterpump is usually (or at least supposed to be) changed with the belt i.e. treated as a consumable because if it lets go there's a fair chance it'll take the belt with it followed by the rest of the engine. If the pump is 'lifed'


    * One that gets lots of Septic lawyers excited
     
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