Heater Core or no? HELP please
Thread Starter
Junior Member
Joined: Apr 2020
Posts: 70
Likes: 6
Mercedes GL550
Heater Core or no? HELP please
Hey guys, so since the end of winter earlier this year my heat hasnt worked properly.
It would get luke warm but only if my 13' GL550 was driven for some time.
Now its barely getting any warmth on the drivers side and cold air on the passenger side.
First MB mechanic told me I probably need a heater core flush.
Dropped it off to the dealer who came to conclusion that I need a heater core replacement and wrote this on the invoice:
"Connect battery charger and xentry, performed quick test, no faults to note, check actuators of hvac system, all functioning properly, drain coolant, remove LF wheel and fender liner, check heater core pump, functioning properly, remove hoses, remove hose at partition wall to heater core, flush heater core, very little flow coming through core. Reinstalled all components, torqued LF wheel 150NM, vacuum filled cooling system with new coolant, road test vehicle, heat is still not strong, vehicle requires a heater core replacement"
So now im calling around to see the prices because I know this is a HUGE job.
One indy MB mechanic says in his 30 years hes never seen a heater core go on a Mercedes.
So I was hoping some of you guys can give me any other alternative to how this can be fixed or if the dealer performed everything it wrote, im out of luck and need a new heater core?
Thanks guys
It would get luke warm but only if my 13' GL550 was driven for some time.
Now its barely getting any warmth on the drivers side and cold air on the passenger side.
First MB mechanic told me I probably need a heater core flush.
Dropped it off to the dealer who came to conclusion that I need a heater core replacement and wrote this on the invoice:
"Connect battery charger and xentry, performed quick test, no faults to note, check actuators of hvac system, all functioning properly, drain coolant, remove LF wheel and fender liner, check heater core pump, functioning properly, remove hoses, remove hose at partition wall to heater core, flush heater core, very little flow coming through core. Reinstalled all components, torqued LF wheel 150NM, vacuum filled cooling system with new coolant, road test vehicle, heat is still not strong, vehicle requires a heater core replacement"
So now im calling around to see the prices because I know this is a HUGE job.
One indy MB mechanic says in his 30 years hes never seen a heater core go on a Mercedes.
So I was hoping some of you guys can give me any other alternative to how this can be fixed or if the dealer performed everything it wrote, im out of luck and need a new heater core?
Thanks guys
Senior Member
Joined: Jan 2015
Posts: 306
Likes: 78
gl450
Did you see this thread? May be helpful as it covers everything from flushing to heater core replacement
https://mbworld.org/forums/gl-class-...l-valve-2.html
https://mbworld.org/forums/gl-class-...l-valve-2.html
MBWorld Fanatic!
Joined: Jan 2016
Posts: 2,757
Likes: 889
From: In the Shadow of the Tetons
2013 ML350 Bluetec
What valves are between the engine coolant loop and the heater core? I remember on my W123 there is a heater control valve that is prone to fail in the closed position; is there something similar on the X166? It would sure cause the symptoms you're feeling.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
Last edited by rapidoxidation; Oct 24, 2024 at 08:54 PM.
Thread Starter
Junior Member
Joined: Apr 2020
Posts: 70
Likes: 6
Mercedes GL550
Did you see this thread? May be helpful as it covers everything from flushing to heater core replacement
https://mbworld.org/forums/gl-class-...l-valve-2.html
https://mbworld.org/forums/gl-class-...l-valve-2.html
What valves are between the engine coolant loop and the heater core? I remember on my W123 there is a heater control valve that is prone to fail in the closed position; is there something similar on the X166? It would sure cause the symptoms you're feeling.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
I’ll ask the dealer tomorrow what shape the coolant was when drained.
thanks for the help
Thread Starter
Junior Member
Joined: Apr 2020
Posts: 70
Likes: 6
Mercedes GL550
What valves are between the engine coolant loop and the heater core? I remember on my W123 there is a heater control valve that is prone to fail in the closed position; is there something similar on the X166? It would sure cause the symptoms you're feeling.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
Seems like WIS would have a coolant flow circuit diagram somewhere.
What shape was the coolant in that got drained? Seems like if the core is clogged there'd be evidence of that in the coolant.
there was blockage though through the core.
