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Hello
Looking for some assistance, please. Mounted on 79k, the 2020 M340d. I sat for around two weeks. Revved the engine and drove a short distance. The coolant temperature is too high, so I got a notification telling me to drive slowly. The red line on the temperature indicator was touching my eye when I looked at it. After 1 minute, I let off the gas and the temperature decreased to the center. Notification vanished. I maintained a consistent temperature as I drove between forty and fifty miles per hour. Auto turned off because fan was still going. At first, I blamed a glitch. Rode it for another lap while monitoring the temperature gauge. At 30 mph, while I'm taking it leisurely, the temperature seems to be fine. As soon as I add any weight, it starts to rise. I checked the coolant level before leaving the car overnight, and it seemed to be OK.
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The temperature of the coolant for the M340D
Ignore the fact that it says oil temperature; for the time being, it doesn't matter whether it's oil or water.
It seems that a defective sensor is the likely culprit; nonetheless, you should have it checked out as soon as possible, jic, by having a fault code scan performed.
Getting back to normal, depending on the oil, can take about 6 or 7 minutes.
First things first, we need to code scan our system.
You may have checked for water in the vehicle, but it's safe to assume it hasn't if you've driven 40 miles or more without any problems.
It seems that a defective sensor is the likely culprit; nonetheless, you should have it checked out as soon as possible, jic, by having a fault code scan performed.
Getting back to normal, depending on the oil, can take about 6 or 7 minutes.
First things first, we need to code scan our system.
You may have checked for water in the vehicle, but it's safe to assume it hasn't if you've driven 40 miles or more without any problems.
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andy_bmw_1965
- Posts: 60
- Joined: Mon Feb 02, 2026 8:37 pm
Instead of oil temperature, some later BMWs display coolant temperature on the cluster. I also double-checked this with AI. The temperature of the oil is not shown. Entering the iDrive is necessary for that. But neither of them gives you the real temperature, like 90 degrees Celsius, just a gauge.
Yes, I have verified that the coolant/water is suitable.
Yes, I have verified that the coolant/water is suitable.
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andy_bmw_1965
- Posts: 60
- Joined: Mon Feb 02, 2026 8:37 pm
Incidentally, I was implying that my drop speed is 40 to 50 mph. As the temperature began to rise, I had to gradually reduce the accelerator to bring it down.
My apologies, but I really don't care about new automobiles and am financially unable to buy one.
Regardless, a fault code scan should be performed as a precaution, just in case (jic). It appears like a defective sensor.
My wife's F20 doesn't have a water or oil temperature gauge, and it annoys me that I have to use an obd device that attaches to the dashboard and displays a bunch of useless temperature data.
Regardless, a fault code scan should be performed as a precaution, just in case (jic). It appears like a defective sensor.
My wife's F20 doesn't have a water or oil temperature gauge, and it annoys me that I have to use an obd device that attaches to the dashboard and displays a bunch of useless temperature data.
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andy_bmw_1965
- Posts: 60
- Joined: Mon Feb 02, 2026 8:37 pm
Sure, I'll have to have the error code read to find out. Yeah, it's frustrating that the new BMWs don't have the old-fashioned temperature displays for the oil and coolant.
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xxxMikexxx
- Posts: 27
- Joined: Mon Feb 02, 2026 8:41 pm
After getting a replacement sensor, everything is OK; my brother had the same issue with a Vaxhall Insignia a few years ago, but that was with a different vehicle.PS: Invest in a real sensor; using a fake one will be a waste of time.