Coolant leak
Thread Starter
Senior Member
Joined: Oct 2017
Posts: 302
Likes: 43
From: Saint Louis
2010 GL550 | 2020 S560
Coolant leak
2010 GL550 127xxx MILES
I've searched and searched for a solution.
It only leaks when the engine is at operating temperature. I crawled underneath and located a hose that about an inch in diameter that runs behind the front bumper between the radiator and the front bumper. I squeezed it and coolant came out rather quickly.
I do have the oil cooler leak however its a very very slow leak. 3 months ago I had a full radiator flush at the dealer due to sludge build up in the overflow tank.
When the GL is parked, I do have a 8 inch puddle under the front left (drivers side) under the vehicle.
Any and all help would be appreciated.
I've searched and searched for a solution.
It only leaks when the engine is at operating temperature. I crawled underneath and located a hose that about an inch in diameter that runs behind the front bumper between the radiator and the front bumper. I squeezed it and coolant came out rather quickly.
I do have the oil cooler leak however its a very very slow leak. 3 months ago I had a full radiator flush at the dealer due to sludge build up in the overflow tank.
When the GL is parked, I do have a 8 inch puddle under the front left (drivers side) under the vehicle.
Any and all help would be appreciated.
Last edited by Yup497; Nov 20, 2020 at 06:42 PM.
Out Of Control!!
Joined: Sep 2018
Posts: 14,692
Likes: 4,584
From: unbegrenzt
2017 GLE350 4MATIC
2010 GL550 127xxx MILES
I've searched and searched for a solution.
It only leaks when the engine is at operating temperature. I crawled underneath and located a hose that about an inch in diameter that runs behind the front bumper between the radiator and the front bumper. I squeezed it and coolant came out rather quickly.
I do have the oil cooler leak however its a very very slow leak. 3 months ago I had a full radiator flush at the dealer due to sludge build up in the overflow tank.
When the GL is parked, I do have a 8 inch puddle under the front left (drivers side) under the vehicle.
Any and all help would be appreciated.
I've searched and searched for a solution.
It only leaks when the engine is at operating temperature. I crawled underneath and located a hose that about an inch in diameter that runs behind the front bumper between the radiator and the front bumper. I squeezed it and coolant came out rather quickly.
I do have the oil cooler leak however its a very very slow leak. 3 months ago I had a full radiator flush at the dealer due to sludge build up in the overflow tank.
When the GL is parked, I do have a 8 inch puddle under the front left (drivers side) under the vehicle.
Any and all help would be appreciated.
Does the X164 GL550 have a coolant circulation pump? I think it does. My W166 circulation pump smells like coolant when at operating temperature, but there is no leak. It's a very small leak from near the hose clamps, as far as I can tell. The circulation pump on the W166 is behind the left headlamp, forward of the front left wheel.
Last edited by chassis; Nov 20, 2020 at 09:03 PM.
Thread Starter
Senior Member
Joined: Oct 2017
Posts: 302
Likes: 43
From: Saint Louis
2010 GL550 | 2020 S560
When I squeezed the hose, coolant came out on my hand directly from the house (yes it was hot). Sorry for the clarification.
My VIN:
4JGBF8GE2AA581225
Pictures to come tomorrow.
Again the coolant hose is at the lower part of the front of the engine and almost runs parallel to the lower front valance.
Thank again.
My VIN:
4JGBF8GE2AA581225
Pictures to come tomorrow.
Again the coolant hose is at the lower part of the front of the engine and almost runs parallel to the lower front valance.
Thank again.
Last edited by Yup497; Nov 21, 2020 at 03:37 AM.
MBWorld Fanatic!
Joined: May 2015
Posts: 1,932
Likes: 291
From: Allentown, PA
'08 GL 320 CDI
Just keep following that hose till you find the leak point - possibly pinhole in the hose - possibly a clamping/connection point. Leaks can be a pain to find sometimes - you're way ahead of the game as you've already narrowed it down. In other words, you've pretty much answered your own question!
Trending Topics
MB World Stories
The Best of Mercedes & AMG
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)
Verdad Gallardo
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun
Verdad Gallardo
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren
Verdad Gallardo
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine
Verdad Gallardo
Flawlessly Restored Mercedes 190E Evo II Heads to Auction
Verdad Gallardo
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know
Verdad Gallardo
Mercedes EQS Gets A Major Update: Everything You Need to Know
Verdad Gallardo
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve
Verdad Gallardo
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping
Verdad Gallardo
Thread Starter
Senior Member
Joined: Oct 2017
Posts: 302
Likes: 43
From: Saint Louis
2010 GL550 | 2020 S560
I traced the hose I saw leaking and it turned out to out connected to the washer fluid headlight cleaner. Washer fluid AND coolant are both blue..
My oil cooler has always had a small leak and I have the seal.. Now that I'm seeing oil this time round im going to start with replacing the oil cooler seal.
Oil has never been low either though.
I chalk this up to another Mercedes mystery.
Thread Starter
Senior Member
Joined: Oct 2017
Posts: 302
Likes: 43
From: Saint Louis
2010 GL550 | 2020 S560
MBWorld Fanatic!
Joined: Jun 2010
Posts: 2,762
Likes: 630
From: Emmett, ID, USA
2007 GL450
The MB coolant is G-05, which is supposed to be yellow / gold.
Supposedly G-11 and G-05 are essentially the same thing.
All this fuss, when there are only a few coolant / system compatibilities that present a real problem.
Senior Member
Joined: May 2007
Posts: 260
Likes: 24
From: Hudson Valley, NY
2005 E55 Black, 2007 GL450 Carneol Red
