WDB
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Post by WDB on Mar 26, 2021 17:17:14 GMT
Esp may be best placed to answer this but anyone can have a go. I was poking about in the data captured by my Mercedes Me adapter and noticed this from my last outing. Now this was a return journey from Reading station (putting Boy1 on a train to Southampton to check out new student digs) so the engine was already warm. It wasn’t a cold day so it shouldn’t have been struggling for warmth. Unfortunately, the app doesn’t give me a history, just the most recent journey. I’ve commented before on the disparity between Esp’s fuel economy and mine, despite having the same engine in similar cars. I’d be interested to know if his reports a different temperature from mine, which might tell me whether I need to replace the thermostat. (This was the one non-routine item I did on the old E220, but that didn’t improve fuel economy.)
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Post by Humph on Mar 26, 2021 18:09:21 GMT
What sort of mpg are you getting and what should it be?
Edit - for what it's worth, mine is rubbish on short journeys but excellent on long runs.
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WDB
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Post by WDB on Mar 26, 2021 18:29:24 GMT
Mine seldom rises above 36 even on a long, steady run. Long term average about 34. E220 was similar. My other big diesels (Volvo, BMW) regularly gave me mid-high 40s. They were manual and lighter; the two automatic Mercedes are both about 30% heavier and consume about 30% more, which doesn’t seem unreasonable — except that Esp seems to do much better.
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Rob
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Post by Rob on Mar 26, 2021 20:04:30 GMT
36 on a steady run doesn't sound much to me. My two petrol 1.4TSI cars with a DSG got a lot more than that. Indeed over the 3 years the Audi A3 and Skoda Superb got that as the long term average and I do a lot of short journeys.
I know your Merc is heavier but seems low.
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Post by Humph on Mar 26, 2021 20:08:01 GMT
Hmm ok, the 250 averaged 45mpg and the 220 gets 49. On a short run, say up to 20 miles it's pretty poor, maybe mid 30s. But journeys of 50 miles + it'll get 51/52. Very short runs of less than 5 miles it's right down at about 23.
Oddly enough, the roof mounted bike rack when empty seems to make little difference. With bikes on, it drops significantly to about 32 even on a long haul. But, on round trips to Milan chokka laden with a roofbox on too, it gets 47.
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WDB
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Post by WDB on Mar 26, 2021 22:18:33 GMT
I know all this. What temperature does your engine run at? 🤓
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Post by Humph on Mar 26, 2021 22:32:33 GMT
No idea, none, it gets hot, I think. Presumably. Who cares?
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Rob
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Post by Rob on Mar 26, 2021 22:39:28 GMT
Diesels over short distances don't have brilliant mpg figures because ... well it's a diesel and therefore thermally efficient and takes time to warm up. I had poor mpg on my Passat CC 170PS diesel because I didn't often do long runs. In all the time I had it averaged about the same as the two 1.4TSI.
But on longer runs the Skoda Superb and Audi A3 could get better mpg. This in part will be the ability to run on two cylinders on light loads.
I look forward to a long run in the BMW. Don't know what it will be like on a long motorway run yet when it starts out charged and when it doesn't have any/much in the batteries.
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WDB
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Post by WDB on Mar 27, 2021 6:26:27 GMT
Great work so far, chaps, on answering a question I didn’t ask with information I already had. Now, forget the fuel economy and tell me what the temperature should be. Please!
I admit that until yesterday I didn’t know that the app could report this data, so I can’t compare the Reading trip with the two longer ones I’ve done recently — although the dashboard fuel computer then showed what it usually does, and the temperature gauge (which presumably uses the same sensor) settled somewhere around the 90 mark.
So yes, I need more information at my end. But two of you have cars that can generate the same data, and before I pay £300 to fix something that ain’t broke, I’d be really interested to know how hot yours gets.
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Post by Humph on Mar 27, 2021 8:36:01 GMT
You'll not hear from Esp until late today at the earliest. He'll be attending to his spiritual side today.
It'll be interesting to know what mpg he gets...
😎
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bpg
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Post by bpg on Mar 28, 2021 17:24:41 GMT
What's the issue ? Don't rag it until the water temp is 70 and preferably when the oil is up too (oil takes a bit longer than water to reach optimum temp). A 5 degree variance isn't that great if you're driving down a dual carriageway then driving in town/traffic. The fan is nowhere near kicking in at those temps, I'm guessing the rises and falls are due to traffic and oil warming up, oil cooler kicking in, auto gearbox coolant.
Those numbers are telling me the car is not cool but it has not been on a run and had time for everything to even out.
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WDB
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Post by WDB on Mar 28, 2021 18:18:04 GMT
I don’t know if there is one, I just wonder if the overall temperature range is on the low side. I’ve had a thermostat fail totally, in my Astra years ago. The needle barely rose out of the blue sector — about 60°C, I think — and fuel consumption shot up. This isn’t doing that; I just suspect the range should be closer to 90 than 80.
I’ll probably get to do a long run again soon. Now that I know where to find the data, I can repeat the snapshot then.
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bpg
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Post by bpg on Mar 28, 2021 18:24:40 GMT
My own experience with diesel is if you are getting poor,or what you consider poor, fuel consumption change the air filter.
I've found with my own Volvo cars the main dealer services skip some filters. The air filter I took out my S60 with full main dealer servicing looked like it had never been changed from the factory. I popped a K&N filter in and the fuel consumption jumped from 37-39mpg to 45+. The fuel consumption data I have back to 2013 when I bought the car backs this up.
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WDB
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Post by WDB on Mar 28, 2021 20:04:52 GMT
That’s a valid shout. I confess I never look at filters; the car is in an MB workshop every year (8000 miles even in a busy year for this one) and I just assume filters are taken care of then. I did manage to change the air filter in my dirtiest, most embarrassing engine — the one in my lawnmower— and that did make a difference, if not to the fuel consumption then to the blue haze that enveloped two gardens either side. Reckon I could tackle this one?
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bpg
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Post by bpg on Mar 28, 2021 21:00:49 GMT
No disrespect to the factory trained specialists in MB service centres but I don't think we're talking NASA rocket science whatever the main dealers try to say.
I reckon you can manage a few clips. Ford took me less time than Volvo, I don't think MB is beyond you.
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