Diesel Owners: I changed my Main Thermostat & cleaned my EGR Valve, NOW CHECK OUT MY RANGE!

So, I changed my main thermostat a couple of days back, and now he runs at a solid 91-92 degrees AT ALL TIME. It pops up to 95-97 in town and the cooling fan kicks in at 97. These temperatures are with the AC off. With the AC on (the cooling fan is pretty much constantly on) the temperature drops to a nominal 86ish degrees.

Before both thermostats were changed, the computer would give me a range of 550-650 miles. Only once have I seen 700 miles. After the EGR thermostat was changed, I got a range of 8-900 miles. So, comparatively, this is quite something.





AND, before you guys start complaining, I know I won't achieve a whole 1k miles out of a tankful, but usually I manage to achieve a couple of hundred mines less that what the computer range tells me. This post is just indicative of what could be achieved, rather than a guarantee that I will get that many miles from the tank.

Also, NO, I'm not resetting the computer and taking a picture of the range, the range is something you can't reset so I'm not cheating... and I know you can get the computer to show 99.9mpg if you reset it while you are already on the motorway and going downhill etc, but if you look on the right you can see that I've driven half an hour and a few miles before taking the picture.







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Changing your Main Thermostat
Guys, don't shy away from this one, it's EASY to do, albeit slightly time taking (took me 2 hours). N.B. I did NOT remove the EGR cooler.

All instructions are as if you are looking at the car from the front. Here are some pictures that go with my description below.
1. Remove bonnet landing panel (10 xT45 screws)
2. Remove plastic panel under that (5 screws) (hex I think).
3. The small water pipe is held in place on bottom left hand side of the fan. (it's deep down, and hard to see, but your hand can follow it). Originally, I thought this step meant [remove pipe from radiator and expect all water to come out]. This is NOT the case, the fan is just holding it in place, giving it support, so it's okay to remove.
4. Unclip 2 electrical wires to radiator and lift fan up and out.
5. Unclip 3 inch rubber pipe from underneath EGR cooler. Let all water drain out. (remove under-panel beforehand)
[total time, 20 mins]

6. Just underneath the EGR valve, there is a hex bolt which holds the plastic piping which feeds to the main thermostat. Remove this to gain a little more flexibility as the pipe is quite rigid.
7. Now, three of the thermostat bolts are easy to access (using the tool on TOP of my engine). The fourth bolt can be accessed with a slightly bendy spanner (This kind of spanner has enough bend in it to access the last, top left bolt). You can only undo the screw a quarter of a turn at a time, but it still beats taking off the whole EGR cooler IMO. Also remember to undo the two metal clamps either side of the thermostat entry and exit supply pipes.
8. Wiggle it apart. It WILL come off, you just need to support the main supply pipe with something like in my picture to move it forward slightly, to gain more flexibility and access.
[total time, 1hour]

9. Refit everything in reverse order.
[total time, 40 mins]

10. Undo the big PLUS screw on the egr thermostat when refilling with antifreeze to help remove air.
11. Follow normal bleeding procedures. Check water level regularly over the next few weeks and top up as more air comes out.
12. Get crazy miles/tank, and a longer lasting engine, and a DPF that regenerates less.
13. Grab yourself a beer and congratulate yourself on saving around £300 + future fuel savings.

B.1. Cleaning the egr valve is handy while you're in there. It's easy enough to do, but just be prepared to spend an hour getting all the sh*t off. Get LOADS of carb cleaner. http://imgur.com/j4CWn If I had time I would take apart the whole egr air inlet and clean it, just like -Antti- did on here, because look at that picture, it really is FULL OF SHIT.

 

Good to see you did it in the end. The must be loads of the diesels running around not up to temp, BMW should really go back to engine temp guages.

 

https://5series.net/forums/topic/119...ck-out-my-mpg/

A couple of days back???

Two weeks ago at least!

Why are you reposting this, what's the agenda?

Anybody can manufacture a OBC readout like that, you do yourself no credit.

 

As i read it he did change the egr thermostat in post 1, and now has sanjsanj changed the "main" thermostat
And again, as I see it, that is pretty relevant Info hé is posting.

 

I am quite pleased with the end result I must say.
Thanks for your help. True say though, every time I see a diesel e60 I have an urge to warn them about operating temperatures!. A temp gauge would be useful, but you can't differentiate between 80 and 90 degrees on them, so I guess people checking the secret digital temp readout isn't a bad thing.




Thank-you Mobmatrix!
Mobmatrix above has got it. 2 weeks ago I did the EGR, and 2 days ago I did the Main.





The points I was making below the OBC picture in the first post were to demonstrate that they were the ACTUAL readings I took directly after filling up and driving. You're probably thinking the short distance makes it an outlier, but here's the current state of my Journey Computer which hasn't been touched since I reset it last:




That was reset 30 miles after filling up (I forgot to reset it at the petrol station), so add 30 to the miles covered there, and divide it by the number of litres I've used thus far (33L), and my average comes out to be 53.1mpg.

Do you still classify 386 miles worth of driving, in 11 hours, and getting 53mpg "Manufacturing"? Because I'd happily invite you to give it a go.

 

I have recorded EVERY tank of fuel since 2006 when my 530D had 15,000 on it.

The MPG has been consistent at 31-33mpg every tank, this is not from the OBC (which in my experience is often up to 10% out) but from actual mileage and by fuel put in.

Which makes me thing that either the running temp is not THAT critical to mpg or I'm very lucky and my thermostats are working well.

Must confess I have not checked the running temps.

 

The readings on my car where 10% higher then the actual consumption. Yep never trust the onboard reading but check them by calculating when you fill up.
I have put in the correction (900 instead of 1000) and now its giving the true consumption.