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Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 24215
Experience:  BEng hons Mech engineering, in auto industry 22 years
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My w212 E250 estate 2011 has a water problem the top hose

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My w212 E250 estate 2011 has a water problem the top hose was callapsing when cooled down new top hose fitted still happened was told sounds like the cap was not allowing the pressure out replaced the cap still happened all this time every so often l had to keep topping the coolant up had the fuel filter houseing renewed still happening found coolant leaking from the top sensor so replaced the thermastat still happening the first thing l had checked was a gas test to check for head gasket or cracked head / block nothing wrong can anybody help please thanks J Bailey.
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Customer: replied 1 year ago.
Carry on thanks.


for the hose to collapse then you must be losing coolant somewhere and so generate a vacuum inside the engine

I'm surprised you haven't overheated it to be honest

As you've already had the gas check for a a water jacket crack then check that the water pump impeller / turbine isn't spinning on its shaft. You should be able to achieve this by removing the bottom hose from the engine and use a screwdriver or similar to feel for the water pump impeller blades, whilst your assistant turns the engine over by hand.

If you can stop the impeller with slight pressure from the screwdriver the pump needs replacing.

Also its possible the belt is slipping so its worth replacing its especially if the rubber ribs are cracked or it looks shiny on flat side of the belt - while its off check that the tensioner and other pulleys all spin freely the exception to this is the AC pump ( if fitted)

I'd also suggest ensuring that you've got all the air out of the system as this sort of episode can leave pockets of air trapped and prevent the coolant from circulating properly.

So check that the small hoses that run from the top of the engine and radiator that run back to the header / expansion tank are free flowing and not blocked

If these are OK then remove the tank pressure cap and run the engine from cold with the heater set to full hot

As the engine starts to warm, squeeze the large hoses running to the radiator to help displace any air - all the time keeping an eye on the level in the header tank, making sure it doesn't drop below the minimum and open any bleed screws built into the top cooling hoses - closing them off as soon as they start to gush water

Once the engine is up to temperature the tank should be quite full. Switch the engine off and leave it to cool

Then top up to the mark once its all cold and replace the cap

Customer: replied 1 year ago.
Thanks very much Matt it has also had a new belt fitted my old one was worn think l will put another water pump on,Ian has crossed my mind about that l also have thought it might be the rad blocked maybe.It doesn't have bleak screws on the system or if it does l can't find them will try water pump,thanks again Matt hope this works ......


something else I should have mentioned is to do a reverse flush of the cooling circuit (remove top hose to rad and use a hosepipe to push water into the engine until you get clear water out of the radiator hose) and top up with 30-50% fresh antifreeze. Also check that the small diameter bleed hoses that run from the top of the radiator and the top of the engine aren't blocked as this allow the air to vent back to the header tank automatically.

Customer: replied 1 year ago.
Wiltry Matt thanks will let you no howl get on

no problem

just get back to me on this post

Customer: replied 1 year ago.
Hi Matt checked the small hoses from the rad to bottle and engine fine no blockage will hopefully do the water pump at weekend.


hopefully that'll be it

just get back to me on here

Customer: replied 1 year ago.
Will do
Customer: replied 1 year ago.
Wasn't able to do it this weekend Matt but hopefully next week .


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Customer: replied 1 year ago.
Hi Matt sorry for the delay l only did the waterpump this friday replaced it with new one from mercedes they said they sell lots of them,looks like they have upgraded them according to the parts guy.Touch wood it is going to have sorted it..

thanks for the update

hopefully thats it

anything else I can help with?

Customer: replied 1 year ago.
Thanks for all your help will let you have a update in a weeks time should no by then thanks very much Matt...

no problem

please can you rate my answer using the star buttons

Matt, Mechanical Engineer
Category: Mercedes
Satisfied Customers: 24215
Experience: BEng hons Mech engineering, in auto industry 22 years
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