horsesuitedfool
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Anyone else noticed their average MPG go down the pan since it got cold!! Mine has dropped by a lot, almost 10mpg according to the computer 
Heater boosters......
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Sp!ke
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Diesels take a long time to warm up so you might bbenefit from following Dieselmans advice and making a rad shield.
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horsesuitedfool
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It is ok when the booster is disengaged but when its switched to auto it seems to drink the diesel!! Too cold to have it off though as i had an older W203 diesel some years ago without booster and i hated it in winter as it was forever cold......
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The heater booster doesn't stay on long, cant make that much impact surely?
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horsesuitedfool
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Seems to, although it needed a new MAF which went on yesterday so will see if that was the culprit......
Do you mean the electrical heater booster or the webasto heater unit?
Iirc the webasto uses 1/2 litre per hour at full power.
6.00 am this morning heater running for 1/2 an hour with the rest button switched on for fan operation and car was moderately warm but more importantly no ice on the front windows.
Ignore me just reread post again and i think you mean the elec powered booster.
Lynall
Iirc the webasto uses 1/2 litre per hour at full power.
6.00 am this morning heater running for 1/2 an hour with the rest button switched on for fan operation and car was moderately warm but more importantly no ice on the front windows.
Ignore me just reread post again and i think you mean the elec powered booster.
Lynall
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I'm meaning the electric heater. I don't think the 203 ever came with the webasto stationary heater?
wardpaa
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The Diesel heaters are an option according to my handbook.
The electical heater booster uses a lot of current and the engine needs to idle up in order to compensate for alternator load which = more fuel.
Have not tried measuring the difference in warm up times so not sure how much difference the booster makes.
The electical heater booster uses a lot of current and the engine needs to idle up in order to compensate for alternator load which = more fuel.
Have not tried measuring the difference in warm up times so not sure how much difference the booster makes.
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Apologies, you are quite correct
I have never seen a 203 with this option though. It would certainly be useful in this current weather
JohnDeere8530
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Electric heater do use some power typically 400w. However an average car producing 130,000W this is an insignifcant amount, far less than 1%. Therefore without accurate equipment to measure specific fuel consumption there is no way anybody would notice this.
Other bigger factors are at play, typically a cold engine and transmission has cold oil, this provides far more resistance to the engine, thus soaking up significatn power when cold.
Other reasons fo reduced fuel consumption when it is cold could be, letting car warm up before getting in, and driving more slowly. Other electrical items such as lights and rear demist, make a insignificant difference due to the reasons explained above.
On another note, aircon is one of the most power hungry optional features on a car, it can typically pull 4,000W from an engine, ie 10x as much as a heater. This typically can reduce you efficiency by about 3 - 4mpg. Perhaps you have this on all the time now to reduce the humidity on the windows, whereas a month or so ago it was not on all the time
If you are seeing big reductions in mpg, I suggest you may have a problem elsewhere. Slow puncture for example. As you know tyre pressure in the winter is always less than that in the summer, perhaps another 3-4psi may help per tyre ?
Other bigger factors are at play, typically a cold engine and transmission has cold oil, this provides far more resistance to the engine, thus soaking up significatn power when cold.
Other reasons fo reduced fuel consumption when it is cold could be, letting car warm up before getting in, and driving more slowly. Other electrical items such as lights and rear demist, make a insignificant difference due to the reasons explained above.
On another note, aircon is one of the most power hungry optional features on a car, it can typically pull 4,000W from an engine, ie 10x as much as a heater. This typically can reduce you efficiency by about 3 - 4mpg. Perhaps you have this on all the time now to reduce the humidity on the windows, whereas a month or so ago it was not on all the time
If you are seeing big reductions in mpg, I suggest you may have a problem elsewhere. Slow puncture for example. As you know tyre pressure in the winter is always less than that in the summer, perhaps another 3-4psi may help per tyre ?
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Has anyone ever got to the bottom of what that appears to be controlled by the a/c button (when heater booster set to auto)?
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Not sure I understand the question Rory..
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Sorry, messed that up.
Take 2:
The heater booster can be set to off, auto or manual, with the manual option controlled by the a/c button.
Why the a/c button, I wonder? What's the connection between the heater booster and the a/c system? If anything, you might want to turn the a/c off when cold, but that would also turn off the heater booster (if set to manual).
What I wondered was whether there is a system, as Honda use, which uses the a/c compressor as a heat pump to warm the car interior up more quickly. Controlling that with the a/c button would make sense.
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IIRC the a/c is disabled at temps below 5C, or is it 8C? either way the same temp the booster cuts in.
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horsesuitedfool
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Ok im confused......!! What type of heater booster has the W203 got?? Does it simply give you warm air for the interior quicker or does it warm the engine up quicker using a block heater of some sort?? My engine appears to warm up quite quickly, certainly as quick as a petrol model so i thought it had some kind of block heater......I dont get warm air instantly inside the car either, it takes 5 minutes or so for that, around same time as a normal petrol model i guess.....
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Mine and I would suggest yours, has the electric booster heater that warms the coolant, speeding engine and cabin warm up. This is not a block heater AFAIK they heat the engine oil, water and erm, block!
With the a/c on auto I don't get any air through until the engine is warm (~40C) and that is in about 3min. If I put the demist on air is blasted through immediately and it starts to feel warm after approx 30sec. By warm I mean not freezing, it's certainly not 22C ....
With the a/c on auto I don't get any air through until the engine is warm (~40C) and that is in about 3min. If I put the demist on air is blasted through immediately and it starts to feel warm after approx 30sec. By warm I mean not freezing, it's certainly not 22C ....
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horsesuitedfool
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Ok i got it now, that makes sense, i thought the engine warmed up quite a bit quicker than may last diesel benz a few years back that didnt have the booster!!
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Well, the booster cuts in at 8C. Car a/c normally cuts out as 3-4C - it would certainly need to (and does) work down to those sort of temps in the UK to cope with our wet weather.
