ScottWeir

2014 E550. So what is this reservoir, and what goes in it? Driving myself nuts trying to figure it out, and no obvious info in owners manual or online search. Is it a coolant reservoir for the turbo intercooler?

What is it, and what goes in it?

konigstiger

Turbocharger Intercooler Reservoir, same coolant as engine.

ScottWeir

Thank you! Interesting that it's smack dab in the middle of the engine but not labelled or listed in the owner's manual.

S. Madman

That is interesting because the 2012 do not have that!! I wonder if the 2014's have the separate coolant lines like the E63?

ghlkal

Interesting find ... yeah, my 2012 M278 doesn't have that.

nota_amg

yep, added in 2014 on the Facelift cars

my 2012 does not have it either

DFWdude

Um wait... Isn't that the turn blinker fluid reservoir?

ScottWeir

I do have some turn blinker fluid if you need it. Looks and smells a lot like home made hand sanitizer

Tom in Austin

So is there separate radiator somewhere to cool the intercooler cooling fluid? Is there a pump to circulate it, a fan to blow air over it, etc.?

nota_amg

Yes, in the passengers side of the front bumper there is a heat exchanger shrouded in a ported housing. The pump is close by...

konigstiger

S. Madman

This looks like the 2012-2013. You have one for the 2014?

dbldpr

On my sons car he has a similar Reservoir on his transmission overflow line. It seems that at high speeds his manual trans gets real hot and instead of the fluid spilling out it goes into a Reservoir and then when it cools off it goes back into the trans.

kojak

Siegmann

It's a separate reservoir for the intercooler heat exchanger, starting in 2014.

Tom in Austin

Correct, Mercedes refers to it as the "low temperature circuit" ... entirely separate from the main coolant system that circulates through the engine block and radiator. There's a small heat exchanger but no pump or separate fan for the low temperature circuit.

Siegmann

No separate fan, but there is a dedicated pump.

moe-idk

My 2013 has a separate reservoir, I think it started sometime in the 2013 model year.

Bigmizike67

Wet wetter, cold AIT's

Chevota

I want some "Wet wetter"...

I drained my little tank and added Water Wetter, and I can't tell the difference
Next stop is draining it all and replacing with maybe 80-90% water and the rest Propylene Glycol, just for pump lube and rad protection. Or maybe Water Wetter, who knows.
I was thinking the bennie might be more about better flow than heat Xfer, but all that matters is if it helps or not.
Also considering water misters in front of the rad, which I think would be awesome. I already have the stuff to do it, except one very important thing; motivation...

The pump for this system has a short life span, but varies. Hard to say but maybe 3yrs to >5? That's based on people who have replaced them, and post about it, but my guess is many/most are unaware it has died. The car will not tell you, so might want to check. It's hard to tell since it only comes on when air gets really hot, but you can jumper it to force it on, or "see" it if you data log. To data log you floor it and the the air temp should drop, then rise slowly and not go very high. How high? I guess maybe 20F but it varies on ambient temp and how long you floor it for. If it climbs to like 130 or more then I'd assume the pump died. You can data log using a cheap app like Torque Pro ($5?) and a cheapie $10 OBD Dongle. Good for checking/troubleshooting other stuff too, totally worth $15.
There are other tools that records the goings on of the engine a lot better, but more $ of course. I have an awesome setup (brag) :p
Anyhooo, if anyone has questions on the pump, jumpering or whatever, feel free to ask. And yes it's very important for peak power, if you care about that, and you should because you have a twin turbo V8...