E60 530d poor fuel consumption - fixed.

[anonymous-user]

I thought it worth sharing my experiences with my 80,000 mile 2005 530d auto which has dissapointing fuel consumption ever since I have owned it - around 30mpg average best and down to 26 during the recent cold spell. A friend suggested it was running too cool - a common problem in BMWs as the thermostats fail and let water go around the rad before the car gets a chance to warm up.
So I check the coolant temp using the "secret" OBD readout on the dash (Google BMW OBD to get instructions) and the car was indeed cool - running at 65 - 80 degrees max, and around 70 most of the time (should be 91 +/- 1C all the time).
I had both thermostats - the EGR one above the manifold and the main one done for around £150 all in and car now running at 91 on the nose after 5 miles gentle driving. The EGR one had definitely gone (I could blow through it) but not sure about the main.
I will report back on the effect on fuel consumption but if you are concerned about yours check the running temp, if low replace the EGR thermostat first (a 15 min DIY job and parts are around £30). If that doesnt help do the main - around 2 hours and fiddly and similar price.
Hope this is helpful
Mark

Edited by drmark on Thursday 13th January 14:19

Edited by drmark on Thursday 13th January 16:18

[phelix]

Yup - been there done that on my 535d. Seems to have picked up the fuel economy by 5-10% so well worth doing. And I get heat much quicker on the cold days as well.