BMW M5 Forum and M6 Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
148 Posts
Discussion Starter #1
My coolant temp gauge was reading low (like 11 o'clock). Dealer replaced the thermostat under warranty. However, it's better but still low (now it's like 11:30). I did a search and it seems a few members have experienced the same thing. What bothers me is that the reading fluctuates a little between 11 and 11:30 position, but never go straight up to 12:00. Maybe the coolant temp sensor needs replacement? Most of other cars I know reach an operating temp and stays put.

Any advice before I take it in again? Thanks.
 

·
Registered
Joined
·
12,774 Posts
KJJ said:
My coolant temp gauge was reading low (like 11 o'clock). Dealer replaced the thermostat under warranty. However, it's better but still low (now it's like 11:30). I did a search and it seems a few members have experienced the same thing. What bothers me is that the reading fluctuates a little between 11 and 11:30 position, but never go straight up to 12:00. Maybe the coolant temp sensor needs replacement? Most of other cars I know reach an operating temp and stays put.

Any advice before I take it in again? Thanks.
I notice some variation on mine depending on driving conditions. Light throttle on the higway, and I am around 11 or 11:30. City traffic in the Florida summer I am at 12 or a shade over. If you drive the car hard, say run 4th on the highway for a while, or keep the revs over 4 grand as you go tooling around you should see the gauge go up a little, but not much. The oil temp should also go up some, more than the temp gauge, but not a great deal of movement. The car has not been tracked (yet) so disclaimer under track conditions.
Regards,
Jerry
 

·
Registered
Joined
·
797 Posts
KJJ said:
My coolant temp gauge was reading low (like 11 o'clock). Dealer replaced the thermostat under warranty. However, it's better but still low (now it's like 11:30). I did a search and it seems a few members have experienced the same thing. What bothers me is that the reading fluctuates a little between 11 and 11:30 position, but never go straight up to 12:00. Maybe the coolant temp sensor needs replacement? Most of other cars I know reach an operating temp and stays put.

Any advice before I take it in again? Thanks.
Can you check for codes? There's a code (69 on the Peake Tool) that gets triggered whenever the coolant temperature sensor thinks the thermostat should open or close and the thermostat doesn't open or close (hope that make sense).

:cheers: Jeff
 

·
Registered
Joined
·
141 Posts
Hey guys, similar thing noted on mine...then suddenly the opposite happened. The guage went all the way to the right, beyond the red zone and stayed there!!! Yet no lights (or sirens) came on. :confused:
Someone else mentioned that this must be due to a faulty sensor or thermostat, so I'm taking her in to the dealer on Saturday.

Not sure why the coolant guage sensor s do this, but I don't think what you're describing is all that uncommon. Cheers.
 

·
Registered
Joined
·
530 Posts
My Coolant gauge rarely reads above 11:30 position. Usually more like 11:00 position, at normal driving and some sport driving. The Oil Temperature does change with applied load, at a noticable rate higher than that of the coolant T°.

I do not know what the corresponding coolant temperatures track to as a function of position on the gauge; but some deviation is quite normal.

Hope this helps a little.
 

·
Registered
Joined
·
4,248 Posts
My coolant guage is also almost always around 11 o clock and never higher then 12 (except the time I had a faulty thermostat sensor). This is normal IMO.
 

·
Registered
Joined
·
797 Posts
TCM said:
...This is normal IMO.
I also believe that, since there's very little variation in the gauge despite how hard you hammer the engine, this is an indication of how robust the cooling system in the S62 to is.

However, I seem to remember someone on the board saying that they believed that the temp gauge was conditioned (electronically) to read over a very narrow range near 12 oclock on purpose and only if there was a failure in the cooling system would it read excessively low or high.

Notwithstanding, I can't believe the engineers would do that AND, if the signal is conditioned somehow, then it would have to be a relatively sophisticated conditioning circuit or algorithm, otherwise you wouldn't see the temperature rise while the engine warms to operating temperature.

I tend to believe that the narrow range is the result of the robustness of the cooling system in the engine.

Jeff :cheers:
 

·
Registered
Joined
·
148 Posts
Discussion Starter #8
Thanks for the response. I feel a lot better now. Just want to make sure the engine is not running "cold". Also I should mention that I do have the powerchip 91 Gold here in CA. The tech asked me if I had ECU programmed. I hesitated but did tell him I had it done more than a year ago and this was something I just recently noticed.
 

·
Moderator
Joined
·
10,445 Posts
I asked this same question about a year ago. With cooler temps, less A/C use, my coolant temp runs around 11 oclock when i'm crusing, with oil temps around 170-180. If i'm pushing it hard, coolant will get up to 12 oclock, oil temp around 210. Hot weather with the ac on, coolant never really goes above 12, maybe briefly on track. Oil temp does climb up to 240 or so if i'm pushing it. This is all normal for the M5, from what i've read.Other bmw's i've owned have a very dampened temp gage, never deviating from 12 o clock, i think the m5's is slightly more accurate.
Mike
 
1 - 9 of 9 Posts
Top