Engine Coolant Flush
05-27-2007, 04:40 PM
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Join Date: Nov 2001
Location: Portland, OR
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2001 CLK320
MB coolant
I'd use regular water to flush out the cooling system.
MB uses synthetic coolant hybrid-OAT (Valvoline Zerex G-05 as one example, which is easily found at most parts stores) for the aluminum alloy engines. The intervals MB typically call for coolant replacement is 3 years. Your dealer could also look up in the WIS for your specific model/year to see if the interval is different. You can also buy the MB-branded stuff through on-line sources as well, but since the Valvoline product is available through the retail outlets its easier to just buy it locally.
The MB spec calls for a lower pH,acidity, and silicates level than is found with the older green color ethelyne glycol coolant or the orange OAT ethelyne glycol based coolant. This is to prevent the coolant from eating away at the aluminum coolant passages in the engine -
The long life "Orange Stuff" aka: Dex-Cool (Organic Acid Technology) was originally promoted as having a 5yr / 100k life by other manufacturers, but many of those mfgr's have backed off that claim. There were issues with intake gaskets (the nitrile rubber seals to be specific) being eaten away by this newer type of coolant as well as cylinder head bolts corroding. There have also been instances of head gaskets corroding with this orange coolant - the "long life" claims of this coolant don't hold up as originally promoted.
The current standard is to periodically test the coolant for pH levels to determine if the acidity level indicates whether the coolant is due for a change. This also applies to the older green color coolants as well.
MB uses synthetic coolant hybrid-OAT (Valvoline Zerex G-05 as one example, which is easily found at most parts stores) for the aluminum alloy engines. The intervals MB typically call for coolant replacement is 3 years. Your dealer could also look up in the WIS for your specific model/year to see if the interval is different. You can also buy the MB-branded stuff through on-line sources as well, but since the Valvoline product is available through the retail outlets its easier to just buy it locally.
The MB spec calls for a lower pH,acidity, and silicates level than is found with the older green color ethelyne glycol coolant or the orange OAT ethelyne glycol based coolant. This is to prevent the coolant from eating away at the aluminum coolant passages in the engine -
The long life "Orange Stuff" aka: Dex-Cool (Organic Acid Technology) was originally promoted as having a 5yr / 100k life by other manufacturers, but many of those mfgr's have backed off that claim. There were issues with intake gaskets (the nitrile rubber seals to be specific) being eaten away by this newer type of coolant as well as cylinder head bolts corroding. There have also been instances of head gaskets corroding with this orange coolant - the "long life" claims of this coolant don't hold up as originally promoted.
The current standard is to periodically test the coolant for pH levels to determine if the acidity level indicates whether the coolant is due for a change. This also applies to the older green color coolants as well.
