SES-coolant temp below optimal thermostat regulating temp

[tsgibbs]

Has anyone gotten this SES error...."coolant temp below optimal thermostat regulating temp" or something of the sort? I have a 2001 X5 (3.0), and I have been getting this error for about a month now. I have cleared the message assuming as long as the vehicle was not running hot, it must be an error. It stays clear for about a couple of days, then it comes back on. Until recently, my temperature gauge would read at approximately 11 o'clock. Now it reads at 12 o' clock, but the error keeps coming up. I also assumed the temperature gauge change to be a function of the ambient temp as well (i.e. driving in colder weather vs. hotter weather). What could be causing this, and how do I remedy this? Any and all help will be most appreciated.

Thanks!

[Zulu95]

Take the vehicle for a drive and then get the actual temperature read. It could be a faulty t'stat or sensor.

[mrbmwx5]

it happened to me ,the car also show that i have multi error ,i replace the thermostat and it took care of it.

[lo_jack]

I would never trust the factory temp "gauge." That is pretty much for decoration. No numbers - no information. I would expect a t-stat problem. Do check the actual coolant temp and see how long it takes to come up to operating temp.

EDIT: I ran a scanner on my 3.0 last night for half an hour of driving after coming up to operating temp and maxed at 204*F, but mostly held at around 201*F and achieved that temp in under 2 minutes of idle.

Temp gauge has nothing to do with ambient. Water temp is the temp of the coolant in the engine, which is heated by the combustion in the engine. Combustion temp in the cylinders makes a certain temp, which the engineers know, and they designed the engine cooling system to maintain this temp under all circumstances, as temp in the cylinders determines the efficiency of converting power from airfuel mix to mechanical energy. When your engine is not hot enough, you are not getting a complete burn of the airfuel charge, thus wasting fuel and losing power. Too hot is also bad.