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Hello All, I have a 2016 w222 that loses coolant after a drive. First warning came after a 1hr drive looked at reservoir, it was half empty. Topped it off after it cooled down. Two day later went for a good drive the warning showed up the following day to add coolant. This time the reservoir was empty. No leaks can be seen under the vehicle, pulled all covers from top of engine can't find any leak. Attempted a pressure test and found nothing. What could it be?? Any assistance would be appreciated. The coolant was also blue, isn't supposed to be pink?? Empty Reservoir
The turbo coolant lines and radiators are notorious for leaking at higher mileage but since you say it's not leaking than it would have to be internal to the engine. What does your oil look like? Milky? Or maybe going into the combustion chamber. Are you 100 % sure it's not coming out and trapped in the pan below the car? Look around the front of the engine near the turbo lines and see if you can see anything. Also look along the edges of the radiators.
Definitely check your oil. Coolant mixed with oil (which looks like a tan milkshake) is notoriously a symptom of a blown head gasket. That is not a common issue with these cars but is a major issue.
When it comes to coolant there are 3 main places it can go- a leak externally, into the oil or into the combustion chamber. If you see no visible signs of leak and the oil is clear then chances are it's being burned off. If that's the case it's almost certainly a head gasket...
One symptom of burning off in the motor is the exhaust is pretty wet with lots of steam out of the exhaust at start up. Also the exhaust has a particular smell to it. The other way to tell is by looking at the spark plugs. If you have a really clean one that means the plug is basically being steam cleaned by the coolant burn off.
Don't discount a slow leak. Coolant evaporates quite nicely and completely off a hot engine, so you may not see any liquid and still have a leak. My car had a slow leak at the cap and I found tell-tale white, crusty residue on the reservoir threads. A $6 cap from Amazon fixed it and no problems since.
I once had a water leak that was going through the cap itself (o-ring or something) we chased it for quite some time before finding it. The water only vented when the water temp was above 220º ( a few pounds of pressure) and since the leak was in the cap itself, the pressure tester had taken it out of the equation so the system would test good, and still leak in normal operation. We found it using some kind of dye.
The turbo coolant lines and radiators are notorious for leaking at higher mileage but since you say it's not leaking than it would have to be internal to the engine. What does your oil look like? Milky? Or maybe going into the combustion chamber. Are you 100 % sure it's not coming out and trapped in the pan below the car? Look around the front of the engine near the turbo lines and see if you can see anything. Also look along the edges of the radiators.
Upon further advised searching I can see where the coolant qound up but still can't locate where it's coming from. vehicle only has only 49k miles. Coolant at bottom
Upon further advised searching I can see where the coolant qound up but still can't locate where it's coming from. vehicle only has only 49k miles. Coolant at bottom
Right in the middle of the picture is one of the coolant lines to the passsanger side turbos. It looks like a backwards "J". Where it meets the block there is also another turbo line that it mounts with that goes to the Drivers side Turbo. You need to look right there for the leak as that is a common point of failure because they get brittle and crack at the fitting going into the block. Get your self a mirror and a flash light and it will be pretty easy to spot. It may only actively drip when the engine is running and up to temp. If it is wet in there you know that will be the leak. Becareful messing with the turbo coolant lines because they can be extremely brittle and break without much effort. I had a X166 with the same engine and that is exatly where mine started. I changed all the lines myself as once you start taking them apart to replace the leaking ones the other will all break. Its not too terribly hard just can be a tight space to work.
Being that I recently purchased this vehicle. I’m going to take it right back to the dealer and have them do the work. Thank you for the wonderful advice.
Definitely check your oil. Coolant mixed with oil (which looks like a tan milkshake) is notoriously a symptom of a blown head gasket. That is not a common issue with these cars but is a major issue.
I checked the oil and it is clear..dipstick and filler cap. Thank goodness.
Being that I recently purchased this vehicle. I’m going to take it right back to the dealer and have them do the work. Thank you for the wonderful advice.
If it does turn out to be the Turbo coolant line, I would highly recommend that you replace all 5-6 of them at the same time. If it is just the one line taht is leaking the others will probably aslo fail sooner rahter than later so might as well get them all done. . Also if it does turn outto be the turbo line you may want to consider replacing the Themostat, Serpentine Belt & Idler/Tensioner pulleys while they have it apart. It is all right there when you take it apart so maybe you could save a few bucks and get ahread of some future maintanence items.
If it does turn out to be the Turbo coolant line, I would highly recommend that you replace all 5-6 of them at the same time. If it is just the one line taht is leaking the others will probably aslo fail sooner rahter than later so might as well get them all done. . Also if it does turn outto be the turbo line you may want to consider replacing the Themostat, Serpentine Belt & Idler/Tensioner pulleys while they have it apart. It is all right there when you take it apart so maybe you could save a few bucks and get ahread of some future maintanence items.
The turbo has its own reservoir as does the Radiator. They each are a closed system. Which one shows a loss the Turbo or the Main Radiator? I assume they were both pressure tested.
The turbo has its own reservoir as does the Radiator. They each are a closed system. Which one shows a loss the Turbo or the Main Radiator? I assume they were both pressure tested.
The turbos are part of the main coolant loop. It is the intercooler that has the seperate resevior
Good decision on making the dealer fix it. However, the coolant should be PINK on a 2016 W222. Someone has been using coolant that is not original for your car. And at 35K miles, it is unlikely that someone replaced the coolant intentionally. I usually drain and replace my coolant every 60K miles just because I'm ****.
Good decision on making the dealer fix it. However, the coolant should be PINK on a 2016 W222. Someone has been using coolant that is not original for your car. And at 35K miles, it is unlikely that someone replaced the coolant intentionally. I usually drain and replace my coolant every 60K miles just because I'm ****.
The W222 can use either the BQ1030004 (blue) or the BQ1030005 (pink) coolant. Not sure if it's OK to mix them, but either one is fine in our cars.
The W222 can use either the BQ1030004 (blue) or the BQ1030005 (pink) coolant. Not sure if it's OK to mix them, but either one is fine in our cars.
As per the dealership in my area, MB went with the pink after a certain year. So it should be pink although it would work with either. Turns out the issue is with the water pump that leaks only when there is a load applied. Pressure test never showed the leak. So according to them, job takes 7 hrs to complete. Will drop it off this weekend to get accomplished by next week.
08-06-2021, 10:35 PM
