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the Other day I was in traffic and noticed my coolant temps shot all the way up and there was a coolant image that appeared on dash. Turned car off and let it cool down. After that I turned the key to accessory mode just before you turn over engine and noticed the temp gauge went to its usual spot then shot all the way back up. Could this be a faulty temp sensor ? The fans came on repeatedly and eventually snaked the battery.Ended up towing the rest of the way home. The following day I popped the hood and noticed the coolant reservoir was slightly low on coolant but not empty. I could see the bottom of black measuring and a little of the reservoir.
I could only find a discussion when that symbol is red, but yours is yellow. Also, did you get an audible alarm when it popped up?
yes there was a audible sound associated with this. Also from a cold start today I put the car in drive after it warmed up just to see what it what do and afterwards I cut the car off only for it not to turn over until the temps came down. Leaning towards possibly a temp sensor. I was hoping at the very least a check engine light would pop up but that never happend.
Did you unplug your oil solenoid and use a pigtail connector to cap the wire harness connector? I unplugged the solenoid on my an M278, cut the pigtail end connectors off a pigtail , plugged pigtail connectors in both the wire harness connector and solenoid connector to prevent water intrusion, wire harness side pigtail connector wires touched each other at some point (not clipped short enough) and blew the fuse for the fan. Simple fuse replacement fixed my issue.
I’ve owned car since last October haven’t driven it a whole lot however I can’t really recall fan being on much after I replaced ac pressure switch. Before then fan would just run all the time but after changing it out it rarely came on.
Yeah coming from gm and Toyota I have lots to learn about Mercedes lol. I’ll do that and see what I come up with. A couple of peeps were telling me thermostat but I wanna see what info I can find before throwing parts at it.
Yeah coming from gm and Toyota I have lots to learn about Mercedes lol. I’ll do that and see what I come up with.
A couple of peeps were telling me thermostat but I wanna see what info I can find before throwing parts at it.
Yes! T-stat is not out of the picture for this.
They become lazy to help overheat what should not.
It's super easy to replace... easier than sparkplugs.
Your issue does sound a bit electrical... use your scanner to look for obvious issues.
Changed out relay for fan it came on but it’s still overheating. Not sure what to check next I was hoping for a thermostat or water pump code but nothing.
Changed out relay for fan it came on but it’s still overheating. Not sure what to check next I was hoping for a thermostat or water pump code but nothing.
is your big fan still showing fault??
It dounds like the relay you changed fixed the fan then how can it overheat now?
Read your live coolant temperature from ECU datastream ... should stay about 200F according to what ECU wants to do with Tstat built-in heater element.
Last edited by CaliBenzDriver; 06-05-2024 at 12:42 AM.
Code isn’t showing up anymore for fan the digital temp on the right where speedometer is was 199 -201fF consistently however the overheat light came on and the temp gauge on the far left went higher towards the max temp. I figured if there was a fault with temp sensor or water pump a code would pop up but nothing. If thermostat is bad at the very least it’s stuck open both hoses very hot which indicates to me it’s circulating.
Code isn’t showing up anymore for fan the digital temp on the right where speedometer is was 199 -201fF consistently however the overheat light came on and the temp gauge on the far left went higher towards the max temp.
I figured if there was a fault with temp sensor or water pump a code would pop up but nothing.
If thermostat is bad at the very least it’s stuck open both hoses very hot which indicates to me it’s circulating.
See if you want to through in a thermostat. It's not that it doesn't open at all but the shaft movement is restricted when cooked too many times for too long. It brings in restricted slower cooling.
It may or may not be entirely that but this won't be be awaste!
Engine extreme heat with limited cooling as other sources such as piston spray cooling disabled by the oil pump solenoid.
An air pocket is also popular... lunch time now!
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05-16-2024, 10:36 AM
