C220 AMG 2014 low coolant every 3-6 is this normal?

[NasC220]

Hello

I have owned my car for over a year now and have had top up the coolant every 6 months, most recently after coolant change it went low after just 3 months. Engine does not overheat and cannot see any visible leaks anywhere. Oil appears to be normal with no unsual colours or milky or thick texture. The only thing noticed is in the coolant tank the coolant has turned a light brown colour even after changing.

2 mechanics have checked and cannot see any visibles. One checked the lines/pipes going to and from the coolant to engine, another did a ramp test peaving car on for 1 hour, no leaks or problem. I mensioned about the topping up every 6 months and they seem to think it's normal?

Any help of advise woyld be much appreciated as I've never come across this issue.

 

[Blobcat]

Hello and welcome,

Not normal at all - if you're not getting a puddle then it's most likely going into the engine or the oil.

 

[KennyN]

If it happened after a coolant change then possibly it wasn't bled correctly at the time.

I had a coolant leak on my previous vehicle but it only happened when the oil cooler valve opened , it leaked into the V of the engine and then evaporated so no visible sign but it did smell of coolant when really warm.

K

 

[onefortheroad]

Hello

I have owned my car for over a year now and have had top up the coolant every 6 months, most recently after coolant change it went low after just 3 months. Engine does not overheat and cannot see any visible leaks anywhere. Oil appears to be normal with no unsual colours or milky or thick texture. The only thing noticed is in the coolant tank the coolant has turned a light brown colour even after changing.

2 mechanics have checked and cannot see any visibles. One checked the lines/pipes going to and from the coolant to engine, another did a ramp test peaving car on for 1 hour, no leaks or problem. I mensioned about the topping up every 6 months and they seem to think it's normal?

Any help of advise woyld be much appreciated as I've never come across this issue.

Check around the fuel filter housing.

 

[AlanGunn]

Had this when i first got my car.
Noticed a stain on the expansion tank so i fitted a new cap job done.
I think the O ring in the cap had gone flat and hard.
Cap was 11 years old.

 

[w204benz]

Had this when i first got my car.
Noticed a stain on the expansion tank so i fitted a new cap job done.
I think the O ring in the cap had gone flat and hard.
Cap was 11 years old.

Thanks for that. I had a "top up coolant" warning last year, but as I had just had the fuel filter housing replaced, I put it down to the system not being properly bled (it was only a cup or so low).
Almost exactly a year later it just happened again (by a similar amount). No signs of leaks, oil is fine, etc. I was getting worried as I understood it was meant to be a sealed system - so where was the water going?

But a bad cap seal would also explain the stains around the area that the o-ring seals on - it was like that when I bought the car and I didn't take much notice as I didn't realise it was the sealing surface for the o-ring until I read the above post.

Gave the whole thing a good clean and hopefully that will sort it. The o-ring looks fine, but I'll probably replace it anyway for peace of mind.

 

[AlanGunn]

For what it cost i just put this one on and not had to top up again.

https://www.amazon.co.uk/gp/product/B006DHXYIY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[AndySlade]

It could also be slowly leaking from your water pump, check to see if staining around water pump.

 

[AndySlade]

Also have a thorough look around the thermostat housing, in particular around where the temperature sensor is positioned into the thermostat housing.

 

[w204benz]

It could also be slowly leaking from your water pump, check to see if staining around water pump.

First thing I checked when it first happened, as I heard it is a common issue on these cars. I was a bit worried to see the area wet, but it turned out to be from washing the car a short while earlier. Thankfully there have been no signs of moisture or staining since.

 

[w204benz]

For what it cost i just put this one on and not had to top up again.

https://www.amazon.co.uk/gp/product/B006DHXYIY/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Good to know, but picking up an o-ring from the local hardware store was quicker (and cheaper).

Looks like it was the problem, as in comparison the original was very flattened - I'm surprised it was only loosing 200ml or so a year. Of course, at that rate it will take a long time to confirm if it's fixed.

 

[AlanGunn]

That was what i thought when i looked at it flattened over time so just tried it.