EXPANSION TANK

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Sat, 13/12/2003 - 18:06
guerdeval
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Joined: 07.11.2003
Location: cornwall

I have just seen an old 300D saloon and it had an expansion tank, given that some members experience their G's running hot would it be possible to fit an expansion tank to an existing radiator?would the extra coolant make any difference?would there be any point?

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Sat, 13/12/2003 - 18:23
#1
mortinson
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Joined: 06.11.2003
Location: Old beehive, Madrid, Spain
EXPANSION TANK

After running a standard W460 300 GD SWB Manual for a number of years in Spain and without any particular preparation -the car was imported used from Germany- I feel that provided that the cooling system is in the proper state you don't need additional cooling capacity, specially in this (lovely) country.

I would flush the cooling system and refill with approved MB fluid, check the thermostat and in nothing cures the overheating (if indeed there's any) recore the radiator.

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Tue, 23/12/2003 - 01:29
#2
Bill Moss
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Joined: 09.11.2003
Location: UK USA & D
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Expansion chamber

The standard 460 has an expansion chamber built in to the header tank, ie the radiator should only be filled to 1/2 to 3/4 inch from top when cold, this allows for expansion. if you fill it to the top you will get run off at running temperature as the rad cap lifts to let excess out.
What you are looking at on later models is the expansion chamber for a pressurised sealed system. by taking the coolant to a higher pressure the temp at wich the coolant boils is higher. water boils at a 100c at standard atmospheric pressure but at higher values at higher pressures. there is an expedential curve between pressure / temp.
Merc rad cores are notoriously prone to scaling, just like your kettle. mainly because much smaller section tubes are used in the cores. the only cure for this is (from experience) a recore of the rad. merc do sell a descaler but the success of this has never been that good. a good back flush can help and blow out the rad from the engine side with air but caution not to damage yourself or the rad fins. If you do this a good tip is to always refill with a mixture of good quality coolant(007 grade from ICI) mixed with demin water.

Bill Moss

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