[cm335d]

I've looked through the forum regarding the right range for the thermostat and wanted to see if anyone thought that mine running at around 180F on the highway with the A/C on at 80mph, (reaching a high of 205F at 50mph pulling up a grade in traffic) would constitute a defective thermostat that could be linked to my SCR Efficiency code? Thanks all, much appreciated.

[M5_1of400]

Originally Posted by cm335d

I've looked through the forum regarding the right range for the thermostat and wanted to see if anyone thought that mine running at around 180F on the highway with the A/C on at 80mph, (reaching a high of 205F at 50mph pulling up a grade in traffic) would constitute a defective thermostat that could be linked to my SCR Efficiency code? Thanks all, much appreciated.

That's a really wide range.. a perfectly functioning Tstat should give you operating temps in the 88-90C or 190-194F

[Persian Whisperjet]

Weird, normally thermostats fail in the "too cold" mode.

[cm335d]

Originally Posted by Persian Whisperjet

Weird, normally thermostats fail in the "too cold" mode.

That's what I saw on all of the posts. I'm thinking to just swap it out for good measure since I plan to do a coolant flush soon since the car has 107k miles.

[Yozh]

There was a confirmation from a member here, named, floydarogers, that SCR efficiency codes are related to failed thermostat. I’ll let him fill in the details.

[Persian Whisperjet]

Originally Posted by cm335d

That's what I saw on all of the posts. I'm thinking to just swap it out for good measure since I plan to do a coolant flush soon since the car has 107k miles.

If the EGR cooler is, um, absent the thermostat swap out is straightforward.

See link for a tutorial in how to swap out the old coolant without major drama.

http://www.e90post.com/forums/showthread.php?t=1443671