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Thermostat fixed 3.0d - improved mpg

Discuss your latest mods or ideas, and anything to do with the BMW X5 (E53).
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Entwicklung34
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Thermostat fixed 3.0d - improved mpg

Post by Entwicklung34 » Thu Dec 31, 2015 9:50 am

Changed my thermostat recently due to the common issue of running cool (temperature on the gauge moving between 1/4 and 1/2 depending on conditions).

Thought i'd post to share some points from experience in doing the job and findings afterwards.

In researching the job I found a lot of useful links quite easily, and felt confident doing it as i've done a fair bit of mechanical work before including thermo's / waterpumps on different cars i've owned. Much of the advice online suggested it was a 1hour job, yet it took me 4hours somehow (including bleeding the system). Some of the things I encountered were:
1. Rusty bolts on the undertray, some of which snapped or were too rusty to even remove.
2. Dropping things into the most bizzare places in the engine bay.
3. I lost much more than the 1 litre of coolant that was suggested on some of the walk-through's... more like 3-4litres.
4. I tried to avoid removing the long gold coloured pipe from the egr, but in the end it had to come off so learn from my mistake!
5. One of the plastic mechanisms holding some wiring to the fan shroud was brittle and snapped... cable tie to the rescue.
6. The fan nut was a pain to undo and re-do, but this was expected.

Perhaps most importantly is what i've found after the change... Fuel consumption has increased from around 19mpg (terrible for the 3.0d in my opinion!) to around 23mpg. I've only done 60miles or so since the change but it's significantly improved as I expected, but not much of this mentioned online in what I found.

Image

I also read somewhere that as well as the operating temperature affecting fuel consumption due to the car staying in 'open loop', it can also affect the shift pattern of the gearbox. I'm hoping this will have some impact on the lurch i've been encountering, but will get back on this after more time/miles have passed.

Hope this is of some use to somebody :D

Edit: For reference, using the hidden menu #7 the coolant temp before the change was only reaching ~65degrees, after it's anwhere in the region of 88-92degrees (optimum operating temp). I found the coolant temp feature on menu #7 very useful for monitoring afterwards to make sure everything was ok and there was no overheating!
Last edited by Entwicklung34 on Thu Dec 31, 2015 10:03 am, edited 1 time in total.

Entwicklung34
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Re: Thermostat fixed 3.0d - improved mpg

Post by Entwicklung34 » Thu Dec 31, 2015 9:04 pm

Also, as I ended up losing more coolant than expected the ratio of water:antifreeze I put back in the car is way off... My new ingenious plan is to drain about 1.5litres out of the system and refill witha. Full bottle of coolant. Bearing in mind there are some rusted bolts I still can't get off the front of the undertray (I had to drop the back end of it down and use it like a waterslide when I did the thermo originally :s ) , what's my best plan of attack? I'm sure there must be a drain plug at the bottom of the rad, but it might be awkward to get at with the undertray situation. Oh the joys! :p

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X5Sport
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Re: Thermostat fixed 3.0d - improved mpg

Post by X5Sport » Thu Dec 31, 2015 10:54 pm

How about removing some from the expansion tank?
:ant: Never anthropomorphise computers. They hate that.

RenoHuskerDu
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Re: Thermostat fixed 3.0d - improved mpg

Post by RenoHuskerDu » Sat Jan 02, 2016 5:50 pm

Darn, I just did mine too, but did not check the mileage first.  And mine is a manual gearbox, so our mpg will not match up in any case.  But in the cold it's a treat to have the heater kick on so quickly.
Reno: Alsace, France = only 30 minutes to Germany der Vaterland!
2011 E70 40d well kitted from the factory, RaceChip 375hp
2005 E53 3.0d, manual gearbox, sport susp, RaceChip 278hp

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toonarmy
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Re: Thermostat fixed 3.0d - improved mpg

Post by toonarmy » Sat Jan 02, 2016 5:54 pm

Sorry for jumping your thread but what sort of driving were you doing I'm in Scotland at the minute drove up fully loaded 4 people and 4 mountain bikes on roof and got 28.5 mpg steady away 50-70 is this unusual I can get her to 33-34 at constant 60-70 unloaded
X5 e53 3.0d 53 plate and Honda vtr1000 fun time

RenoHuskerDu
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Re: Thermostat fixed 3.0d - improved mpg

Post by RenoHuskerDu » Wed Jan 06, 2016 10:30 pm

My consumption went down from 10.2 lit/100km to 8.2 lit/100km.  That's a huge difference.  In UK mpg it's 27.7 mpg up to 34.4 mpg!

All that just with the thermostat renewed.  Wow.
Reno: Alsace, France = only 30 minutes to Germany der Vaterland!
2011 E70 40d well kitted from the factory, RaceChip 375hp
2005 E53 3.0d, manual gearbox, sport susp, RaceChip 278hp

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crash
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Re: Thermostat fixed 3.0d - improved mpg

Post by crash » Thu Jan 07, 2016 9:06 pm

Noticed my MPG dropping off lately and thought it was just a result of my impatient/ over enthusiastic driving but have noticed temp gauge has dropped to 1/4 so mine is due a replacment!

Just out of interest where did you purchase your new thermostat from? And if not direct from BMW do you know who the original OEM Manufacturer is? Not a fan of budget patent parts due to the failure rate i have had on various previous vehicles i have fitted them to!

X5-D-Sport
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Re: Thermostat fixed 3.0d - improved mpg

Post by X5-D-Sport » Fri Jan 08, 2016 11:49 am

Try Euro Parts & Andrew Page... these two will usually give a good price & options of OEM or copy..

Additionally, they will often quote Valeo as a cheaper copy - However VALEO make these parts for BMW & brand them under the BMW banner...

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Re: Thermostat fixed 3.0d - improved mpg

Post by Entwicklung34 » Fri Jan 08, 2016 1:06 pm

Hey all... still not got round to fixing the coolant:water ratio, hoping to get to it soon.

My general driving is 98% inner city driving, so mileage is never going to be good really. On the motorway trip home from buying the car it did mid-30's which I was pleased with.

I did so much research on the thermostat that in the end I bought a genuine bmw one from the dealership. It was £48 I think... and although I could have gotten another part for around £30 I felt safer with the genuine part. It heats up like it should now and the Mpg has definitely improved after a few hundred miles by like 3mpg.

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Re: Thermostat fixed 3.0d - improved mpg

Post by X5-D-Sport » Fri Jan 08, 2016 8:13 pm

Good news all round, and it the part will pay for its self soon any way.
Peace of mind, and the smile while driving an X5 is worth that little bit extra they cost to maintain..

that said, I put some 30k onmine last year... and its cost me about £500 for that mileage.
my tyres have done over 20k now & still legal & safe, esp after resetting the front cambers to stop the tyre scrubbing..

I live this car  :)

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