Thermostat Price Insanity?
Thread Starter
Junior Member
Joined: Aug 2024
Posts: 16
Likes: 0
S560
Thermostat Price Insanity?
I have a 2020 S560 sedan. I'm getting a check engine light, which when read, is code P0128. I'm guessing this likely means the thermostat is going bad? Is there a way to tell if it's just the sensor instead? I went to look for where to order a new thermostat and pricing, and it seems like the thermostats are only sold as the whole housing? Is that right? Wondering if there's an aftermarket option for just the thermostat, but haven't found one yet. I was floored to see a $745 price tag for a damn thermostat housing, with no option seemingly to order just the thermostat by itself. Anyone have any experience with this and recommendations?
MBWorld Fanatic!
Joined: Mar 2018
Posts: 1,073
Likes: 596
From: Florida
18 AMG GTC and 22 F150 Limited. Past owner 16 Maybach, 17 Brabus Smartcar, 06 Ford E150, and 22 G70
Thinking about this one I would say your engine is certainly not overheating since the code is indicating that its too cool on the coolant temp. I think if it was my car I would clear the code and see if it comes back. My thoughts are there is no damage to come from this and it could have just been a computer flub. Not the first time I have had to reset the Benz computer for something or another.
Senior Member
Joined: Apr 2023
Posts: 473
Likes: 301
2014 S63 2010 ML350 Bluetec 2009 SL550
The M273 motor generation before these DI motors introduced the electronic thermostat. So yeah. all generations of the V8 from 2007 and later have an electronic thermostat and it's not cheap to replace.
MBWorld Fanatic!
Joined: Sep 2014
Posts: 1,173
Likes: 431
S600
The ideal operating temperature for an automotive engine is 212ºF water and closer to 230ºF oil.
Cooler operating temperatures lead to <slightly> more wear*:
a) as the oil may not be thin enough to provide cleaning to the piston ring package.
b) the oil may not be out-gassing its water-vapor
c) the engine parts dimensions may be slightly out of size/shape**.
(*) 1 hour of that temperature is nothing close to the wear of a single cold start-up.
(**) unless the engine break-in was done at those lower than engineered temperatures.
{{This is simply data I got from Bob-Is-the-Oil-Guy.}}
Cooler operating temperatures lead to <slightly> more wear*:
a) as the oil may not be thin enough to provide cleaning to the piston ring package.
b) the oil may not be out-gassing its water-vapor
c) the engine parts dimensions may be slightly out of size/shape**.
(*) 1 hour of that temperature is nothing close to the wear of a single cold start-up.
(**) unless the engine break-in was done at those lower than engineered temperatures.
{{This is simply data I got from Bob-Is-the-Oil-Guy.}}
Super Member
Joined: May 2011
Posts: 975
Likes: 270
From: Fort Worth TX
2020 S560, 2014 SLK55 (Prev. 2016 S65, 2013 SLK350, 2008 CLS63, 2006 E350, 2006 CLS500, 2005 C230K)
Bad news
The labor to remove and install a thermostat on the 176/177 will make you forget about the cost of the part.
MBWorld Fanatic!
Joined: Jan 2024
Posts: 2,515
Likes: 900
From: DFW
SL63
It’s too bad that the insanely priced tag, only goes in one direction.
Because on the other end of extremely overpriced, is the extremely cheap.
For an item or product to be insanely priced inexpensively, it would have to be stolen property, somehow fraudulent, or found at a garage sale after endless searching.
Because on the other end of extremely overpriced, is the extremely cheap.
For an item or product to be insanely priced inexpensively, it would have to be stolen property, somehow fraudulent, or found at a garage sale after endless searching.
Trending Topics
Super Member
Joined: Jul 2006
Posts: 623
Likes: 131
From: pittsburgh
'25 740i; '15 targa4s; '24 cayenne
yep. i had the same issue on my '20 s560. took it to the dealer and waited 10d or so to fix. tear the engine down 'to get to it' then many days of bringing the engine up to temp and letting it sit to cool down and test and retest. it's a long-assed process. don't know about $ as my was warrantied, but i can only imagine the cost of this outside the warranty given what it took to fix this relative simple kit.
MB World Stories
The Best of Mercedes & AMG
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
10 Most Reliable Mercedes-Benz Models You Can Buy Used
Verdad Gallardo
MBWorld God!
Joined: Dec 2019
Posts: 32,322
Likes: 6,310
Car was in the shop for about a week. Covered under warranty.
https://cimg9.ibsrv.net/gimg/www.mbw...a4855e0198.jpg
https://cimg9.ibsrv.net/gimg/www.mbw...a4855e0198.jpg
MBWorld Fanatic!
Joined: Mar 2005
Posts: 1,032
Likes: 77
From: Wash. D.C.
'20 S63
No idea......two of the wheels had curb rash when I purchased the vehicle. Thermostat went out after about Two (2) weeks of owning the vehicle.
Last edited by xabo; Apr 25, 2025 at 05:58 PM.
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,617
Likes: 1,214
From: Phoenix
222 S-65
Damn.... Another perfectly good reason to drive a bent-12 powered car. Old school wax pellet thermostat that is utterly reliable and inexpensive to replace if needed.
FWIW every manufacturer using Disney thermostats has the same issue and they are all D-U-M dumb priced + ridiculous effort to replace as somehow the thermostat housing includes many connections for hoses that go all over the damned place in search of problems. Then we are shocked when that plastic junk breaks cuz well... plastic in the cooling system is such a fine idea.
FWIW every manufacturer using Disney thermostats has the same issue and they are all D-U-M dumb priced + ridiculous effort to replace as somehow the thermostat housing includes many connections for hoses that go all over the damned place in search of problems. Then we are shocked when that plastic junk breaks cuz well... plastic in the cooling system is such a fine idea.
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
Damn.... Another perfectly good reason to drive a bent-12 powered car. Old school wax pellet thermostat that is utterly reliable and inexpensive to replace if needed.
FWIW every manufacturer using Disney thermostats has the same issue and they are all D-U-M dumb priced + ridiculous effort to replace as somehow the thermostat housing includes many connections for hoses that go all over the damned place in search of problems. Then we are shocked when that plastic junk breaks cuz well... plastic in the cooling system is such a fine idea.
FWIW every manufacturer using Disney thermostats has the same issue and they are all D-U-M dumb priced + ridiculous effort to replace as somehow the thermostat housing includes many connections for hoses that go all over the damned place in search of problems. Then we are shocked when that plastic junk breaks cuz well... plastic in the cooling system is such a fine idea.
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,976
Likes: 1,344
From: Cincinnati
2010 E350 4Matic
Note to self. Remove S560 from consideration of a used car purchase. I redid my E-Classes thermostat and flushed the system one Saturday morning. Doubt it cost me $100.
A friend of mine had a new GMC pick-up truck which needed it's thermostat replaced and it took a couple of days of labor to tear it apart and put it back together. Can remember my friend asking "What genius millenial engineer thought that was a good idea?"
A friend of mine had a new GMC pick-up truck which needed it's thermostat replaced and it took a couple of days of labor to tear it apart and put it back together. Can remember my friend asking "What genius millenial engineer thought that was a good idea?"
Last edited by MBNUT1; Apr 27, 2025 at 06:54 PM.
Member
Joined: Oct 2015
Posts: 136
Likes: 29
2015 S600, 2014 E550 4-Matic
MBWorld Fanatic!
Joined: Feb 2012
Posts: 2,617
Likes: 1,214
From: Phoenix
222 S-65
Your 222 has a 279 with individual coils. No more coil pack and voltage transformer drama we got to deal with in a 275 powered car.
MBWorld Fanatic!
Joined: Oct 2002
Posts: 4,976
Likes: 1,344
From: Cincinnati
2010 E350 4Matic
MBWorld Fanatic!
Joined: Jun 2015
Posts: 9,109
Likes: 4,593
From: Maryland
2024 S580
What you have to understand is this car (and every other car like it) is designed for performance first, and repair and maintenance cost second. It's not designed for you to buy it when its 5 years old and drive it until its 15 years old and not have to pay for any repairs. That's a Lexus ES. You can't even expect that with a Lexus LS (I know, I've had 4). If you are concerned about maintenance cost, no car like this is for you that's just the bottom line. Just get a warranty, or just be happy with a much less complex and more reliability focused car.
SPONSOR
Joined: Apr 2021
Posts: 846
Likes: 559
From: San Jose, CA
11 E550, 16 AMG GTS, 13 S550
damn I thought my M278's thermostat was expensive, this is 2x and then some! I knew it was a 222 thread though before I clicked it one way or the other
the physical thermostat doesn't break, the seal between the electronics and the not-electronics gives and you end up with a fault where it stays open by default, These have been a pain in the *** since the earliest MAP thermostats. I remember when the M273 came out people were pissed that they were $100+ and not the lil $12 duders that sit in the hose connection
the physical thermostat doesn't break, the seal between the electronics and the not-electronics gives and you end up with a fault where it stays open by default, These have been a pain in the *** since the earliest MAP thermostats. I remember when the M273 came out people were pissed that they were $100+ and not the lil $12 duders that sit in the hose connection
__________________
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
Alpha European Autotech
Purchase Amsoil at 25% off from me
Chris Tran, Retired Alpha European Autotech Owner
Amsoil Independent Dealer #7236674
