Mixing of coolant

[smithcd]

So I was parked up for the night on holiday and I had a message from my local Mercedes service centre that my 2015 E220 S212 was low on coolant. The only coolant available in the town was OAT so I had to fill the reservoir with ~400mL OAT. I know you should not mix IAT with OAT coolant and I believe my merc has SiOAT or Lobrid coolant which is based on OAT… am I ok to run the 400mL OAT which will be now well diluted within the cooling system or do I need a flush and drain ASAP? I couldn’t find any conclusive reputable sources online. I haven’t seen any further drops in coolant volume so far. TIA

 

[optimusprime]

So Mercedes let you know that your car was low on coolant, is that right ? How dose that work ..

 

[noogieman]

So Mercedes let you know that your car was low on coolant, is that right ? How dose that work ..

Digital telepathic mindreading perhaps?

 

[Trickythemerc]

If in doubt drain and flush. In the absence of the right coolant I would have topped up with H2O

 

[BlackC55]

You could have topped it up with just water.

Just get it changed when you can.

 

[smithcd]

So Mercedes let you know that your car was low on coolant, is that right ? How dose that work ..

Yeah I assume it is done through Mercedes Me… they email me when a service is due as well… Big Brother alert lol

 

[smithcd]

If in doubt drain and flush. In the absence of the right coolant I would have topped up with H2O

Yeah if I had thought about it for more than a minute that would have been the best idea… I had a long drive ahead of me and panicked… thank you for the response!

 

[noogieman]

If in doubt drain and flush. In the absence of the right coolant I would have topped up with H2O

Shouldn't it be distilled water in the coolant not tap water?

 

[optimusprime]

Anything is better than nothing ...i have used both in the past . Inhibitor witll stop any corrosion.

 

[Uky]

Purchasing "original" Mercedes coolant, the instructions on the plastic bottle says mix with ordinary tap water. It does not explicitly say "distilled".
Reason one could be that the coolant chemistry prevents corrosion. Reason two is that some vehicles uses a level detector that measures Ohmic resistance in the coolant. Distilled water har a high resistivity. Tap water has lower resistivity. Using distilled water could risk false level alarms.