Engine temperature overheating?
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W211 E270 cdi 2004
Engine temperature overheating?
Hi,
For the last couple of mornings, on kickdown (with rpm over 3k) the engine temperature goes well above 120C (in the IC). I switch off the AC before kickdown. It comes down though at 100C immediately when I take my foot off the throttle.
I would like to point out that my Engine Temperature would reach to 100 or 105C within 5-10 km of driving in the morning (outside temperature in early 30s in my area). So I am assuming that thermostat is working as it should. I can hear the auxiliary fan coming on too at that temperature (though it is quite loud), i can hear it with windows closed inside cabin at idle speed.
I have recently changed
- expansion water bottle since it was giving error message 'Check coolant level', after changing the bottle the message disappeared.
- flushed old coolant and put new MB 325.0 coolant (Green) (4.5 Litres) mixed with distilled water. My cooling system requires 11.6 litres as per my car's manual.
Any pointers are welcome.
For the last couple of mornings, on kickdown (with rpm over 3k) the engine temperature goes well above 120C (in the IC). I switch off the AC before kickdown. It comes down though at 100C immediately when I take my foot off the throttle.
I would like to point out that my Engine Temperature would reach to 100 or 105C within 5-10 km of driving in the morning (outside temperature in early 30s in my area). So I am assuming that thermostat is working as it should. I can hear the auxiliary fan coming on too at that temperature (though it is quite loud), i can hear it with windows closed inside cabin at idle speed.
I have recently changed
- expansion water bottle since it was giving error message 'Check coolant level', after changing the bottle the message disappeared.
- flushed old coolant and put new MB 325.0 coolant (Green) (4.5 Litres) mixed with distilled water. My cooling system requires 11.6 litres as per my car's manual.
Any pointers are welcome.
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Joined: Jun 2016
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W211 E270 cdi 2004
Thanks for your response.
I am relying on visually reading from the temperature guage. It may be 92C but from the temperature guage in instrument cluster I am reading it as 100C? Not sure. I think the thermostat is working because if I turn the heater on it works fine.
Thermostat - The fan kicks in as soon as the temperature reach 95-100C mark. If I turn on the heater hot air comes out of the vents. I have tried kickdown while heater is running and the temperature stays at 100 - 105C. (its 40C in my area)
Aux Fan - See above. If the car is on 100C mark and on idle after a couple of minutes, fan starts to slow down. I am presuming that this is working as it should.
Radiator - How can I check the radiator, obviously there are no leaks from it.
I see no obvious leaks on water pump either and the car is not running low on coolant either.
I am relying on visually reading from the temperature guage. It may be 92C but from the temperature guage in instrument cluster I am reading it as 100C? Not sure. I think the thermostat is working because if I turn the heater on it works fine.
Thermostat - The fan kicks in as soon as the temperature reach 95-100C mark. If I turn on the heater hot air comes out of the vents. I have tried kickdown while heater is running and the temperature stays at 100 - 105C. (its 40C in my area)
Aux Fan - See above. If the car is on 100C mark and on idle after a couple of minutes, fan starts to slow down. I am presuming that this is working as it should.
Radiator - How can I check the radiator, obviously there are no leaks from it.
I see no obvious leaks on water pump either and the car is not running low on coolant either.
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W211 E270 cdi 2004
Update : I have driven the car over two days with light foot on the throttle. It runs fine, temperature stays at 100C as per guage. But on kickdown or hard acceleration it goes well over 110-120 range? Any suggestions or ideas? Could it be a blockage in radiator?
Member
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From: Toronto
2009 e class 2012 ml350
it can be a blockage but unlikely, i would try a new thermostat, sounds like its stuck closed (if you have a m272 its very common), when you have the rad hose off also remove the lower hose if you want to check for blockage and blow on it, should take no effort to blow the air trough the coolant
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MBWorld Fanatic!
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From: V E G A S
1922 Ford Model T / no OBD
Get infra-red thermometer for troubleshooting.
Could be bad thermostat, could be your radiator lost its efficiency, could be worn water pump.
When you have engine overheat, pull over and measure top of the engine, where the upper hose comes out, the other end entering the engine back and radiator in different points.
Point the thermometer to metal whenever you can and avoid pointing at rubber hose as this will change the reading.
Could be bad thermostat, could be your radiator lost its efficiency, could be worn water pump.
When you have engine overheat, pull over and measure top of the engine, where the upper hose comes out, the other end entering the engine back and radiator in different points.
Point the thermometer to metal whenever you can and avoid pointing at rubber hose as this will change the reading.
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Thread Starter
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Joined: Jun 2016
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W211 E270 cdi 2004
Thanks.
I have a different guage than yours but my engine temperature stays exactly where yours is. i.e. ~100C. It goes to 120 on kick down though and it has been one of my worries. I want to nail it before I throw any money on parts on radiator, pump etc.
I have a different guage than yours but my engine temperature stays exactly where yours is. i.e. ~100C. It goes to 120 on kick down though and it has been one of my worries. I want to nail it before I throw any money on parts on radiator, pump etc.
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W211 E270 cdi 2004
While driving this afternoon, i was stuck in traffic for about an hour with outside temperature at 40C and AC running the whole time, the engine temperature never passed the 100C mark.
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From: V E G A S
1922 Ford Model T / no OBD
I usually drive diesels, who convert most of the fuel into HP, so can't tell for sure, but engine keeping 100C in 40C weather and heavy traffic would mean no worry to me.
You can't expect radiator +- 10 years old to perform like new one.
Even MB coolant will develop some boiling stone over a decade.
You can't expect radiator +- 10 years old to perform like new one.
Even MB coolant will develop some boiling stone over a decade.
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W211 E270 cdi 2004
Update : I decided to check the coolant temperature via Climate control diagnostics (by pressing Recirc - Off button on climate control panel). Code No. 8 value which was coolant/Engine temperature went upto 92C and Aux fan started at that temperature.
The temperature went upto 100C on climate control screen which was consistent with the temperature guage on instrument cluster panel.
This morning while I try to run the diagnostics again the same value was reading as 40C whereas the Temperature guage in Instrument cluster was 100C.
Which sensor should I be looking to replace? Coolant or Engine Temperature Guage?
Secondly, Could it be the cause of car's overheating problem that I was having earlier? My understanding is that if sensor is reading 100C as 40C then thermostat valve is not opening up allowing the coolant to circulate?
Any help would be much appreciated.
Thanks in advance.
The temperature went upto 100C on climate control screen which was consistent with the temperature guage on instrument cluster panel.
This morning while I try to run the diagnostics again the same value was reading as 40C whereas the Temperature guage in Instrument cluster was 100C.
Which sensor should I be looking to replace? Coolant or Engine Temperature Guage?
Secondly, Could it be the cause of car's overheating problem that I was having earlier? My understanding is that if sensor is reading 100C as 40C then thermostat valve is not opening up allowing the coolant to circulate?
Any help would be much appreciated.
Thanks in advance.
MBWorld Fanatic!
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From: V E G A S
1922 Ford Model T / no OBD
Have you been able to locate the sensors?
On older car coolant and engine temp sensor was the same thing, while thermostat was independent mechanical unit.
My 320 BT has computer-controlled electro-valve instead of thermostat and frankly I am not looking into troubleshooting the system.
If the sensor shows 40C on hot engine, it has to go, but again, where da heck is it?
On older car coolant and engine temp sensor was the same thing, while thermostat was independent mechanical unit.
My 320 BT has computer-controlled electro-valve instead of thermostat and frankly I am not looking into troubleshooting the system.
If the sensor shows 40C on hot engine, it has to go, but again, where da heck is it?
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W211 E270 cdi 2004
It turned out to be a bad thermostat. I changed the radiator earlier based on the wrong diagnosis by my mechanic. After changing the thermostat, the temperature now stays at 98C which I think is normal in 35C ambient temperature.
Thanks to the forum members for pointing me in the right direction.
The wrong diagnosis by my mechanic cost me a radiator and crankshaft sensor which had gone bad after overheating.
Thanks to the forum members for pointing me in the right direction.
The wrong diagnosis by my mechanic cost me a radiator and crankshaft sensor which had gone bad after overheating.
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From: In the Shadow of the Tetons
2013 ML350 Bluetec
IIRC the cabin heater circuit is in no way a part of the thermostat plumbing so even with a t-stat that is stuck completely closed you'll still get plenty of heat out the vents. Sorry you went down the wrong road there; it sounds like your problem could've been fixed a lot sooner.
Glad you got it though! The thermostat was the first thing I had to change on my CDI because the engine wouldn't heat all the way to proper operating temperature. As has been said: Common problem.
Glad you got it though! The thermostat was the first thing I had to change on my CDI because the engine wouldn't heat all the way to proper operating temperature. As has been said: Common problem.
