Cluster Temperture Red Hot

[DoubleAIm]

Got a 2002 E53 3.0i with the temperature instrument cluster needle pegged to red but the red light doesn't come on. It only happens on the first start of the day in the cold after about 5 min drive, once I see the needle pegged, i pull over and restart the e53 and its back to normal. I have checked the coolant level and any leaks which is all normal. I am thinking it's the temperature sensor for the gauge cluster that is faulty but I'm not too sure which one it is. The one by the radiator hose or the one in the thermostat that gives the readings to the cluster gauge? Anyone can point me to the right sensor would be greatly appreciated. Thanks in advance.

[andrewwynn]

Start by using the cluster hidden menu to see what value for temperature the computer is seeing. The needle is a trinary indicator not really a gauge. It will flip to noon at about 65C and stay there until something like 110C (the precise # I'm not sure). If the needle gets its value from a different sensor you can determine if the needle I just reporting incorrectly.

Otherwise if the thermostat is sticking shut it's possible a restart gets it to open. An IR thermometer will give you an approximate temperature if you measure the lower hose or heater hose.


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[DoubleAIm]

Originally Posted by andrewwynn

Start by using the cluster hidden menu to see what value for temperature the computer is seeing. The needle is a trinary indicator not really a gauge. It will flip to noon at about 65C and stay there until something like 110C (the precise # I'm not sure). If the needle gets its value from a different sensor you can determine if the needle I just reporting incorrectly.

Otherwise if the thermostat is sticking shut it's possible a restart gets it to open. An IR thermometer will give you an approximate temperature if you measure the lower hose or heater hose.


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You mean the hidden menu on the MID? Unfortunately, my screen is broken/pixelated so bad that I can’t make anything out. I’m pretty sure it’s a temperature sensor and not the thermostat cause when it goes red hot and I continue to drive it for another 15mins or so and do a quick power cycle, the needle goes back to normal, about 1/3. If it was the thermostat, the needle would have gone right back up into red. The problem I’m facing now is which temperature sensor under the hood.

[mihai]

if you have a bluetooth/wifi OBD2 scanner, connect it, install torque (lite) on ur phone - it's free- and check what temperature is that one indicating.

[andrewwynn]

Hidden menu is on odometer. My MID screen is a mess (readout is Klingon) but my dash is fine.

Normal would be high noon or you mean when slightly cool after not driving ?

I had a similar problem happen where I drove maybe 10 minutes and suddenly in spite of the ambient of below freezing, red temp on the cluster gauge. I stopped and while engine still running I opened the hood and felt the heater hose and it was maybe 150°F. I power cycled and it snapped back to life working properly.

I didn't have other problems until I noticed a month or two later I couldn't get cabin heat if ambient was below freezing. Replaced thermostat and no problems since related to coolant/heat until a week ago when my reservoir sprung a leak. I'm betting you are having a premintion of thermostat failure just like mine. The thermostat is wired I don't know if it's a sensor a heater a valve or a switch but I'm betting the electrical component of your t stat is freaking out and the "Emergency mode" is to flag overheat so you will pull over and investigate.

Check coolant level goes without saying. Engine cold get the bobber to float without hitting the top of travel (assuming similar to M54 engine)


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[DoubleAIm]

I have a OBD scanner that i can use the next time this happens and see the temp readings.

This usually happens every time on the first drive in the morning from the e53 sitting over night. Once I do a power cycle and continue driving, its back to normal and wont happen again all day until sitting overnight for the next morning.

[andrewwynn]

You definitely need to get an actual temp reading. When my tstat failed I drove for most of a year never getting to closed loop running rich because of the moronic dash gauge saying everything was fine but my engine never got over 70C. You can use the hidden menu to watch the temp. It's menu item 7.


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[cn90]

I assume you have > 100K miles.
Start researching "cooling system overhaul".
I posted some DIYs on this topic.

[DoubleAIm]

Didn't happen today since it was a bit warmer, around 8C. Tried looking into the hidden menu but I'm not sure how. I only got one button on the cluster so I hold that down then turn key to position one, it only shows 1.0, 1.1, 1.2 etc. can't get to 7.....

[andrewwynn]

I have same basic cluster.

With people button pressed turn key to on then go to 19 and stop. Wait until it says off then tap once. It will switch back to 1. At that point tap 6 times to get to 7 and stop. You can go back around if you over shoot. 19 is unlock cluster menu. Make sure coolant level is full when cold first.


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