Temperature Swing
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Joined: Oct 2006
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Temperature Swing
Hello guys,
My 04 e class is on a temperature swing lately. On idle or stop and go traffic temp will go up till 100 degrees celcius. It drops on steady or highway driving. It used to always remain around 80. Codes are not showing anything regarding the thermostat. Any advice what might be wrong?
My 04 e class is on a temperature swing lately. On idle or stop and go traffic temp will go up till 100 degrees celcius. It drops on steady or highway driving. It used to always remain around 80. Codes are not showing anything regarding the thermostat. Any advice what might be wrong?
MBWorld Fanatic!
Joined: Aug 2011
Posts: 3,184
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From: Highlands Ranch, Colorado
2014 BMW M235i
It seems natural to me that with warmer weather (I assume you are in North America) this might be the case with the engine idling amongst a higher ambient temperature. But that is quite a large temperature difference, so that probably isn't it - just a thought.
I would check engine coolant levels first, it is possible that the coolant has degraded over time or is not at an adequate level to provide cooling while stopped. Maybe a bleed and refill of the cooling system is in order? A visual inspection of all radiator tubes and pipes and its overall condition might point you to the problem. I haven't heard of this specific issue yet, but again I am no expert, so that's just my opinion. Good luck
**EDIT: After doing a bit of research there are a few other factors that might be contributing to this, so I would have them checked out by an indy or the stealer. Keep in mind I am not a mechanic so I might be wrong about some of the engine's specifics.
1) The coolant pump could be going bad due to age, therefore not circulating enough engine coolant with a decreased capacity
2) If this model of engine has a fan/fan clutch, that could be going bad and not engaging at the proper times (not needed when forced by moving through air)
3) Obstructed radiator - when is the last time you cleaned or inspected the radiator?
4) Possible coolant clogging, obstructed flow can lead to such issues
No one on here can truly know what the issue is, but I realize you are just looking for advice - my advice, take it to a dealer or trusted indy and have the system checked out. I know I am often an advocate of doing that *expensive* option but you don't want to risk more expensive damage on the aluminum block or heads if temperature swings become more extreme.
I would check engine coolant levels first, it is possible that the coolant has degraded over time or is not at an adequate level to provide cooling while stopped. Maybe a bleed and refill of the cooling system is in order? A visual inspection of all radiator tubes and pipes and its overall condition might point you to the problem. I haven't heard of this specific issue yet, but again I am no expert, so that's just my opinion. Good luck
**EDIT: After doing a bit of research there are a few other factors that might be contributing to this, so I would have them checked out by an indy or the stealer. Keep in mind I am not a mechanic so I might be wrong about some of the engine's specifics.
1) The coolant pump could be going bad due to age, therefore not circulating enough engine coolant with a decreased capacity
2) If this model of engine has a fan/fan clutch, that could be going bad and not engaging at the proper times (not needed when forced by moving through air)
3) Obstructed radiator - when is the last time you cleaned or inspected the radiator?
4) Possible coolant clogging, obstructed flow can lead to such issues
No one on here can truly know what the issue is, but I realize you are just looking for advice - my advice, take it to a dealer or trusted indy and have the system checked out. I know I am often an advocate of doing that *expensive* option but you don't want to risk more expensive damage on the aluminum block or heads if temperature swings become more extreme.
Last edited by AMGAffalterbach; Apr 9, 2012 at 10:28 PM.
Thread Starter
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Joined: Oct 2006
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Thank you,
I have actually replaced the radiator recently. The car is at the stealer and will request they look at the points you have mentioned. I thought perhaps someone had this issue before and is why i posted here... apparently not.
Thanks once more AMGA
I have actually replaced the radiator recently. The car is at the stealer and will request they look at the points you have mentioned. I thought perhaps someone had this issue before and is why i posted here... apparently not.
Thanks once more AMGA
Senior Member
Joined: Aug 2011
Posts: 356
Likes: 19
From: RI
2017 S550 4matic
have antifreeze tested at shop, bleed system of any air, check fans make sure they are operating properly/plugged in, replace thermostat if necessary.
The variance between 80-100*c is 176-212*f. For some perspective, my E500 in direct sunlight idling on an 80*f day will sit right around 90*c. It shouldn't vary *THAT* much with air going through the radiator, as this would indicate an issue with the cooling system.
The variance between 80-100*c is 176-212*f. For some perspective, my E500 in direct sunlight idling on an 80*f day will sit right around 90*c. It shouldn't vary *THAT* much with air going through the radiator, as this would indicate an issue with the cooling system.
