Strange engine temperature gauge variations (Video inside) Any ideas?
Thread Starter
Newbie
Joined: Jul 2012
Posts: 9
Likes: 0
2008 C350
Strange engine temperature gauge variations (Video inside) Any ideas?
I've been having the following problem for the past 4 days or so. My temperature gauge is going up and down, and the following icon flashes on my dashboard; 
The temperature rages from the middle, all the way to sometimes above 100 degrees in a matter of seconds, it just jumps up and down.
I took the car to the shop, and they ran the scanner but they found nothing, claim everything is normal when clearly it isn't.
Here's some video of the issue, never mind the low fuel warning, just look at the temperature needle gauge and the icon that is there.
Strange thing is that it sometimes goes away on its own and the car goes back to normal.
The temperature rages from the middle, all the way to sometimes above 100 degrees in a matter of seconds, it just jumps up and down.
I took the car to the shop, and they ran the scanner but they found nothing, claim everything is normal when clearly it isn't.
Here's some video of the issue, never mind the low fuel warning, just look at the temperature needle gauge and the icon that is there.
Strange thing is that it sometimes goes away on its own and the car goes back to normal.
Senior Member
Joined: Sep 2011
Posts: 374
Likes: 1
2008 c350 sport
Well i think you have two message on the dash, one which is the low fuel which is nothing but i think the second message is the coolant message. Did you check if you need to add some more coolant into the car???
Thread Starter
Newbie
Joined: Jul 2012
Posts: 9
Likes: 0
2008 C350
Thanks for the reply. I did and even at the shop with my mechanic. Everything looked and felt normal, all the levels, and even the scanner was normal. Even today it showed again, but the strange thing is that after 5 or 10 minutes of driving, temperature goes down to normal and the dashboard warning is gone. Strange indeed.
Member
Joined: Nov 2010
Posts: 197
Likes: 1
From: Australia
C220 CDI SLK 200
Thanks for the reply. I did and even at the shop with my mechanic. Everything looked and felt normal, all the levels, and even the scanner was normal. Even today it showed again, but the strange thing is that after 5 or 10 minutes of driving, temperature goes down to normal and the dashboard warning is gone. Strange indeed.
Could be a thermocouple failure
Thread Starter
Newbie
Joined: Jul 2012
Posts: 9
Likes: 0
2008 C350
That's exactly what I think. Either the engine is too hot or it isn't. In my opinion it can't be too hot for five seconds then a little less hot for another 5.
Last edited by mookiebomber; May 3, 2013 at 03:38 PM.
MBWorld Fanatic!
Joined: Jul 2007
Posts: 1,351
Likes: 90
From: Germantown, MD/Rehoboth Beach, DE
2024 GLS450
That said, my gauge sits a bit higher than what is in the video at normal operating temperature.
Trending Topics
Thread Starter
Newbie
Joined: Jul 2012
Posts: 9
Likes: 0
2008 C350
Any other opinions here? I have taken it to yet another shop this week, the mechanic claims there's nothing wrong with the car, that it doesn't heat up, yet I still get the problem. It still goes away after a few minutes and the car runs normal.
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
Junior Member
Joined: Nov 2012
Posts: 71
Likes: 1
2008 Mercedes C300 4Matic Sport Sedan
The thermostat fails in an open position, so it's either flowing or not, and in winter months, that means the car would have a difficult time getting and staying up at operating temperature. The check engine light will also eventually come on for the thermostat failing because the car reads a temperature that's not quite normal operating temp (which is a preset value).
You can order just the temperature sensor without getting the thermostat, but if you order a thermostat, it comes with the sensor too. I wouldn't do the thermostat based on this though.
Junior Member
Joined: Oct 2013
Posts: 56
Likes: 1
From: French Riviera
2011 C180 Coupé (prev '99 CLK200)
Pascal
Newbie
Joined: Aug 2013
Posts: 5
Likes: 0
From: Netherlands
ml500 w164
engine tempature failure solved w164
6 months ago i replaced the temprature control module inside the car because it was in farenheit and i'm used to celcius, so i bought one on internet.
Now 6 months later strange engine temprature readings and engine temprature failures.
i put the old one in now and u can gues it, just did a test drive and it was fine, pffffff, hope it stays that way else i will delete post.
So i've learned now, only replace parts that belong to your chassis number, it saves u a lot of frustration.
thanks to the knowlage of one of the last good car mechanics, he said all tempature thingies are connected, even that inside the car, that set me thinking.
Now 6 months later strange engine temprature readings and engine temprature failures.
i put the old one in now and u can gues it, just did a test drive and it was fine, pffffff, hope it stays that way else i will delete post.
So i've learned now, only replace parts that belong to your chassis number, it saves u a lot of frustration.
thanks to the knowlage of one of the last good car mechanics, he said all tempature thingies are connected, even that inside the car, that set me thinking.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Electronic 4 Way thermostat.
https://mbworld.org/forums/5939612-post25.html
If you run too cold the car will throw a P0128.
https://mbworld.org/forums/5939612-post25.html
If you run too cold the car will throw a P0128.
MBWorld Fanatic!
Joined: Nov 2007
Posts: 2,078
Likes: 4
From: NYC
2012 C300 4Matic
Another vote for a bad temp sensor here. It's obviously moving MUCH more than it would under any normal circumstances. Those changes in the temp gauge have absolutely nothing to do with running the heater or coming to a stop - they're far too quick and wide for that.
Someone else mentioned air pockets which is also a possibility, but I'm 99% sure this is an electronic issue. The readings are erroneous. It's got to be the sensor or wire, or ECU.
Glyn, do you really think it could be that variable with a bad thermostat?
Someone else mentioned air pockets which is also a possibility, but I'm 99% sure this is an electronic issue. The readings are erroneous. It's got to be the sensor or wire, or ECU.
Glyn, do you really think it could be that variable with a bad thermostat?
Last edited by acr2001; Feb 18, 2014 at 10:15 PM.
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 192
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
acr ~ I don't think it is a bad thermostat. I just wanted to point out that a greater temperature fluctuation is now normal with the electronic 3 disc stat. The gauge should be well damped and not jump around. There could well be an issue with the cluster or temp sensor.
(((
Newbie
Joined: Jun 2014
Posts: 2
Likes: 0
2008 C350
Fan Module
How did you know it was the fan control module versus the temp sensor?
I have a 2008 C350, with the following symptoms:
coolant warning, temp needle going up and down, a/c blowing but no cold area.
I have a 2008 C350, with the following symptoms:
coolant warning, temp needle going up and down, a/c blowing but no cold area.
Newbie
Joined: Apr 2014
Posts: 2
Likes: 0
From: Netherlands
2008 C63 AMG / 1976 VW Golf
I have the same issue. Already someone that can verify what the problem is? And how about that fan module, where is it located? in the fan assembly? (I have the 600W in my W204 part. A2049066802 and pictures of that fan don't show any module like the big silver module that is on the 400W version)
