Temperature sensor goes up, OBDII shows proper temp
 

I have a 2001 X5 3.0 and I noticed that the temperature needle sometimes will shoot up to the red (Needle full to the right). When it first started happening, it scared me, thinking something was wrong. I have an OBDII scan tool connected to my Dynavin unit via bluetooth so I have Torque to diagnose any codes it shoots. When I check the temperature, it isn't running extremely hot (something in the 160F range) Any ideas?

Did you have the scanner connected at the same time your temp needle was showing it as running hot?

No, but it is odd that the needle is stuck super hot, yet the obdII shows 160-180.

Reason I asked was if it were the case, it may have been an electrical issue where as now I would point towards a temp. sending unit possibly on its way out.

Wasn't aware about that part. Is it a simple fix? I was hoping it was something simple. I just did the alternator and belts this weekend and that was a bitch to do. Hoping it isn't the thermostat. I don't feel like taking the whole thing apart again. I will probably have to. I need to fix a nasty oil leak.

Never had to do it. The coolant temperature sensor screws into the drivers side of the head towards the firewall.

when you did alternator and belts, did you drain the coolant? and then refilled it? you may have air bubble trapped in the system, the I6 are known for that issue. the whole thing boils instantly, and then cools down real fast... but, when it boils, it can create some damage...

if you did not touch the cooling system, then it could be the temp sending unit, as mentioned above... unlock the OBC, and read the temp from the cluster (the values should be same as on your BT reader, but, just in case, if they are different)...

And put some basic info about your car into the sig line, makes it easier to help out...

When I had a crack in my expansion tank, my temperature gauge use to do that. I would shut the engine off and start it back up and everything would be fine. And actually i discovered the cracked expansion tank when i was troubleshooting this issue. Just something to look at.

Unlock the cluster and monitor your coolant temp for a few days. You don't want to overheat M54 engine, even just for a mile or two. The head is aluminum and will warp under high heat.

thermostat is failling.