W212 Coolant Change
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Newbie
Joined: Jul 2021
Posts: 14
Likes: 16
2015 X166 GL550
W212 Coolant Change
2014 E350 4Matic. Alright, similar to my last thread on rear diff fluid, this seems like it hasn't been covered enough and it's super easy.
What you need:
- Pair of any sort of pliers.
- 2 gallons of Zerex or Mercedes coolant.
- 8mm deep socket and ratchet
- That's literally it.
Steps:
- Get the car in the air using whatever method you choose, ramp, jack and stands, or lift.
- Remove the very first plastic under-carriage guard, by "very first" I mean most forward. You'll find a single 8mm bolt nearest the bumper, and many towards the side and back.
- Open the coolant reservoir on the passenger (US) side of the car just under the hood.
- On the drivers side (US) underneath the car you'll find a plastic petcock on the lower part of the small side of the radiator, there's no markings, no yellow paint, no red petcock, just a black plastic valve on the side of the black plastic radiator housing.
- Turn the one possible petcock valve you can find in a clockwise circular motion. (Have a 5L catch-pan ready underneath the drain hole located right next to it.)
- Wait until the drainage stops to about a slow dribble.
- Turn the petcock counter-clockwise to stop the flow, but do not tighten down too much or you will break the plastic.
- Fill the overflow reservoir whose cap you removed earlier until it stops drinking fluid.
- Start the car, turn the climate control to "HI" max fan, both passenger and driver sides.
- Give 'er a few revs (2-3k RPM) until the thermostat opens at 80C on the gauge, then let it idle.
- Monitor the coolant reservoir whose cap is still open, top off the fluid one time, then just start adding coolant until about 3/4" below the top of the fill hole. It will bounce around for a while.
- When the coolant level stops moving at idle, drive around for a bit, get 'er warm, cycle the heat on and off.
- Check the coolant level after the car cools, make sure it's roughly 3/4-1" below the bottom of the fill hole.
Done.
Feel good about this one, you probably didn't make too much of a mess, it was easy.
What you need:
- Pair of any sort of pliers.
- 2 gallons of Zerex or Mercedes coolant.
- 8mm deep socket and ratchet
- That's literally it.
Steps:
- Get the car in the air using whatever method you choose, ramp, jack and stands, or lift.
- Remove the very first plastic under-carriage guard, by "very first" I mean most forward. You'll find a single 8mm bolt nearest the bumper, and many towards the side and back.
- Open the coolant reservoir on the passenger (US) side of the car just under the hood.
- On the drivers side (US) underneath the car you'll find a plastic petcock on the lower part of the small side of the radiator, there's no markings, no yellow paint, no red petcock, just a black plastic valve on the side of the black plastic radiator housing.
- Turn the one possible petcock valve you can find in a clockwise circular motion. (Have a 5L catch-pan ready underneath the drain hole located right next to it.)
- Wait until the drainage stops to about a slow dribble.
- Turn the petcock counter-clockwise to stop the flow, but do not tighten down too much or you will break the plastic.
- Fill the overflow reservoir whose cap you removed earlier until it stops drinking fluid.
- Start the car, turn the climate control to "HI" max fan, both passenger and driver sides.
- Give 'er a few revs (2-3k RPM) until the thermostat opens at 80C on the gauge, then let it idle.
- Monitor the coolant reservoir whose cap is still open, top off the fluid one time, then just start adding coolant until about 3/4" below the top of the fill hole. It will bounce around for a while.
- When the coolant level stops moving at idle, drive around for a bit, get 'er warm, cycle the heat on and off.
- Check the coolant level after the car cools, make sure it's roughly 3/4-1" below the bottom of the fill hole.
Done.
Feel good about this one, you probably didn't make too much of a mess, it was easy.
Last edited by SlyAsA; Jul 15, 2021 at 04:40 AM.
Super Member
Joined: May 2018
Posts: 505
Likes: 288
From: Sammamish, WA
2011 E350 Wagon, 2010 GL450
Make sure you dilute the coolant with distilled water if it's not already. 50/50 works for most situations, but do some reading and see what's right for you. The stuff you buy from the dealership is undiluted. I do like the legit Mercedes coolant since it's so reasonably priced ($20 for a gallon of undiluted).
Also, this is a great chance to replace your thermostat if it hasn't been already. It's a wear part and they do go bad!
Also, this is a great chance to replace your thermostat if it hasn't been already. It's a wear part and they do go bad!
MBWorld Fanatic!
Joined: Dec 2020
Posts: 2,412
Likes: 1,482
From: 122W, 37N
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
also be sure to get the /right/ Mercedes coolant, they switched formulas mid production on the w212 and they aren't compatible. I forget the specifics, I think the previous version was G48, which is blue, and the new one is violet or something and is known as G40. ah, 325.0/326.0 are the blue G48 coolant, and the violet-pink G40 stuff is 325,5/326.5... Google is suggesting the cutoff date was April 2014
MBWorld Fanatic!
Joined: Dec 2020
Posts: 2,412
Likes: 1,482
From: 122W, 37N
2016 E350 4Matic wagon, 2019 Ford Expedition, 2019 Chevy Bolt EV
btw, the gold Zerex G05 is what Mercedes from the 1980s used, I put it in our W124's with M103, M104 straight 6 engines... its not what Mercedes specifies today. I think G05 and G48 are 'compatible', pure G48 (blue) lasts twice as long as gold G05, so if you use G05 plan on replacing your coolant more frequently. Violet/Pink G40 lasts even longer, but I do not believe is at all compatible with any of the prior formulas.
