E93 overheating alarm but temp remain constant

tilua · 06-29-2014, 01:02 PM

2008 335i
So I was driving and all of sudden my dashboard coolant light warning appears in yellow than immediately goes to red on the display. The symbol that looks like the thermostat over the water level. My temperature gauge still shows the normal operating temperature.

I pulled over and turn off the engine and let it cool down. A while after I started the engine to see of the cooling fan is still working. It does.

I'm guessing it's a bad water pump? Since the water doesn't circulate, the temp sensor might be taking the reading from the cooler (or stagnant) part of the coolant. Thoughts? Appreciate the help.

drunkenup · 06-29-2014, 01:12 PM

temp gauge in our cars is the oil temperature, and while your coolant might be boiling hot, oil will still be reasonably warm. It could be your water pump, I would check for the telltale codes.

tilua · 06-29-2014, 01:29 PM

Quote:

Originally Posted by drunkenup

temp gauge in our cars is the oil temperature, and while your coolant might be boiling hot, oil will still be reasonably warm. It could be your water pump, I would check for the telltale codes.

Oh that is good to know. I have an OBD reader but could not pull any code for this kinda issue I believe.

tilua · 06-29-2014, 01:44 PM

Ok so I drove home and let the car cool down. As suggested by others on here, I then open the coolant reservoir cap and start the engine to check if the water pump is still running. It does.

So the only thing left is the thermostat. But I thought thermostat fail open so it shouldn't cause the overheat. Not sure what else to do here.

stashtrey · 06-29-2014, 02:11 PM

What he ^^^ said. Oil temp on gauge. Your water pump is toast or you have s coolant leak somewhere.

Before my pump went out I had the plastic coolant line that runs from the passenger front end across the top of the radiator to the driver front corner....rupture! Its a shitty little plastic tube that connects to good sized rubber coolant hoses. At 80k miles mine was brittle and exploded coolant all over my engine bay...pouring over the fan and spraying it all over everything. Car went from normal to loss of power in a matter of seconds.

Everyone should inspect that tube regularly to ensure it isn't cracking. $10 part that can ruin your engine.

06-29-2014, 01:02 PM	#1
tilua Private 19 Rep 97 Posts Drives: 2008 335i convertible Join Date: Oct 2011 Location: Houston iTrader: (0)	E93 overheating alarm but temp remain constant 2008 335i So I was driving and all of sudden my dashboard coolant light warning appears in yellow than immediately goes to red on the display. The symbol that looks like the thermostat over the water level. My temperature gauge still shows the normal operating temperature. I pulled over and turn off the engine and let it cool down. A while after I started the engine to see of the cooling fan is still working. It does. I'm guessing it's a bad water pump? Since the water doesn't circulate, the temp sensor might be taking the reading from the cooler (or stagnant) part of the coolant. Thoughts? Appreciate the help.
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06-29-2014, 01:12 PM	#2
drunkenup Captain 214 Rep 988 Posts Drives: 2009 135i, 2021 F150 Join Date: Sep 2013 Location: NJ iTrader: (1)	temp gauge in our cars is the oil temperature, and while your coolant might be boiling hot, oil will still be reasonably warm. It could be your water pump, I would check for the telltale codes.
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06-29-2014, 01:44 PM	#4
tilua Private 19 Rep 97 Posts Drives: 2008 335i convertible Join Date: Oct 2011 Location: Houston iTrader: (0)	Ok so I drove home and let the car cool down. As suggested by others on here, I then open the coolant reservoir cap and start the engine to check if the water pump is still running. It does. So the only thing left is the thermostat. But I thought thermostat fail open so it shouldn't cause the overheat. Not sure what else to do here.
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06-29-2014, 02:11 PM	#5
stashtrey Lieutenant Colonel 294 Rep 1,834 Posts Drives: 08 E90 335xi TiAg Join Date: Dec 2012 Location: Sacramento, CA iTrader: (8) Garage List 2008 E90 335xi Sedan [0.00]	What he ^^^ said. Oil temp on gauge. Your water pump is toast or you have s coolant leak somewhere. Before my pump went out I had the plastic coolant line that runs from the passenger front end across the top of the radiator to the driver front corner....rupture! Its a shitty little plastic tube that connects to good sized rubber coolant hoses. At 80k miles mine was brittle and exploded coolant all over my engine bay...pouring over the fan and spraying it all over everything. Car went from normal to loss of power in a matter of seconds. Everyone should inspect that tube regularly to ensure it isn't cracking. $10 part that can ruin your engine.
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