One for HenryM3 and X5 Sport (or anyone else!)

[X5Sport]

The engine has a viscous coupled fan on the front and there is a second (electric) fan just behind the radiator which runs whenever the climate control is running.  This second fan will vary in speed depending upon demand for cooling and the actual air temperature.

The viscous coupled one may or may not turn gently with the engine running and can be stopped fairly easily when the engine is cold (don't try it it unless wearing suitable protective clothing and with a cold engine!) but will engage if the engine exceeds a predetermined temperature.

If the a/c doesn't click under the bonnet and/or the fan doesn't spin up then you have an issue with the system.  Loss of refrigerant is very common and systems must be run regularly to prevent seal failures.  Typical gas losses are approx 15% per year so a regas every 5-6 years is not unusual.  I never turn mine off.

[henrym3]

Wht are you changing the stat.

[Upex]

Cheers x5sport, need to have a look, as it never stood out lol. Although sounds about right so will have a genders.

Thanks for the check up fan guide, I'll make sure they doing what they should when able to start her again.

Henrym3, thinking of changing stat as gods know when it was last (if ever done) and although the gague has always got to middle and stayed there, obd2 says the temp when I last went out never got above 74deg and it was a decently warm day and long enough drive that she should have been up to full temp easily. Given all the stats I've seen are 88deg openers, this one must be sticking open, at least to a degree (assuming fans check out of course).

[Smeeagain]

[quote="henrym3"]
I don't see your doing the vehicle any harm, there probably is an argument that you could get even better consumption if running a higher temp but probably not much, 1 or 2 mpg. Must admit I haven't researched what temp' a 3.0l diesel thermostat should open. Just as a side note, check your viscous fan isn't locked on and or your electric fan isn't running all the time. Either of these situations would keep your temp low. If your happy with the vehicle, then leave well alone.
Next for X5Sport I'm getting my readings from having one of those digital volt readers plugged into the cigarette lighter socket and then I just look in the window and get the reading. Would that be enough draw to keep the vehicle awake. BTW the digital volt reader when tested against a multimeter gives the same reading so it's fairly accurate.
[/quote]

To your point, how do I research the correct temp for 3.0 Diesel should be open/run at?

Smee

[Upex]

All shops I've checked for a star for mine all offer 88deg stats only, so should be running about that or more, given no lower or higher alternatives. Easy check and give you a steer

[henrym3]

Like wise all I can find are 88 degrees and from previous experience the running temp' will usually be 5 to 8 above that. However all this previous experience was thrown out the window when they started opening the stat with a heater element fed from the DME.

[Smeeagain]

[quote="henrym3"]
That to me is very low, especially for a turbo engine, does it take longer than normal to warm up, are you getting good fuel consumption, Hopefully someone with a similar engine will come on and confirm or not. Can't believe you have a thermostat that opens way down at the very low 70's. My guess is that it may be stuck partially or fully open. You should have full heat coming out the heater in around 3kms of normal driving, although it is hard to tell in this good weather.
Well done on getting into the hidden menu, you'll be able to find faults you didn't know existed.
[/quote]

So I took the car on a long run this week. By a long run I mean Portsmouth to Edinburgh and back via Nottingham. Highest temp I saw was 84c ......

[henrym3]

I still think that's a bit low if your running the standard thermostat, I'd say you should be in the low 90's, when I looked you should be running an 88 degree stat so your running temperature will be a little above that. If running below the stat opening temperature that would suggest it' partially or fully open all the time.

[Smeeagain]

That's what I thought, but would rather the engine was slightly cooler than hotter, so will most likely leave as is for now
Smee

[henrym3]

As a reference point my newly fitted 80 degree stat runs at 82/84 degrees on normal days and these last few days where we've seen 25c + I have seen 87/88c. I'm much happier with these temperatures than 100+. I have not known the electric fan to cut in whilst driving but it has on a few occasions after switching off. I assume this is heat soak from the coolant in the block up towards the 99c temperature sensor, the fan will run for no more than 10 seconds, on some occasions it will cycle twice. 
I have also noticed a considerable drop in GB temperatures as well.

[Pinewood]

I had a 2005 530d and that is too low for the regen to tale place. I suspect your main thermostat (common problem). The smaller one is easier to change, so swap that and then see where the temp gets to. You should be in the low 90's iirc

[Horizon]

[quote="Pinewood"]
I had a 2005 530d and that is too low for the regen to tale place. I suspect your main thermostat (common problem). The smaller one is easier to change, so swap that and then see where the temp gets to. You should be in the low 90's iirc
[/quote]
It's an E53, so doesn't have a DPF to regen, and doesn't have an EGR cooler/ thermostat
So not as important