View Single Post
      01-20-2017, 11:56 AM   #77
mob17
Major General
mob17's Avatar
United Kingdom
400
Rep
5,623
Posts

Drives: E92 335D
Join Date: Mar 2012
Location: East Midlands, UK

iTrader: (5)

Quote:
Originally Posted by TorqueAddict View Post
Quote:
Originally Posted by TDIwyse View Post
As another data point... changed my thermostat this week. Previously the car would warm up to ~172-176F, unless in town stop and go driving, where it might get to mid 180's. New stat car warms up to ~186-190F. ......

I'm curious if those posting significant fuel economy benefits from changing their thermostat could describe their before/after coolant temps, and plot hand calculated mpg results over an extended period of time before/after their thermostat change? That would give some interesting comparison to see if the trend line significantly changes.
If your car was reaching 172-176 (77-80 C), your thermostat was most likely fine. All i could get my car to was 60-63, doesn't matter how'd i drive. No hand calculated MPG's but my tank with similar driving styles and routes used to last me ~570-650kms max. After the replacement, on winter fuel, i hit 780Kms on the tank, which is quite noticeable.

Now within 10-15 minutes of my drive to work the temperature rises to 80+ C easily, and car drives and behaves differently. Tranny is more smoother. I have been driving this car for over 4 years now - everyday. I can feel the difference in behavior. May be it never got out of warm up cycle ever (never in closed loop)

Another thing that i can relate to this is glow plug controller/glow plugs. Mine failed last winter, which caused me to monitor temperature. According to BMW training document, the glow plugs also work intermittently if your engine isn't warm enough - as a result low temps = overworked controller and plugs hence leading to failure.
My glow plug controller has failed i think. I get some rough starts when its cold. I haven't replaced it as i thought i have deleted my dpf that the glow plugs are then used just to start.

If i dont replace what could happen? Should i, as i dont have a dpf?
Appreciate 0