# Mercedes Benz Blue Tech ??
**URL:** https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044
**Category:** Factual Questions
**Created:** [December 10, 2015, 4:11am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044 "2015-12-10T04:11:00Z")
**Posts on this page:** 12
**Page:** 1
### Author:  [@Nightaudit](https://boards.straightdope.com/u/Nightaudit)
#### Post date: [December 10, 2015, 4:11am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/1 "2015-12-10T04:11:00Z")
I’m looking at buying a 2014 Mercedes E class diesel. couple of questions before I buy…
exactly what is the blue tech system? and what happens if I never refill the system. just for FYI the last Mercedes diesel i had was a w123 1978 300d and that thing was like a Timex watch… all i needed to do is change the oil and that was about it. I hit a antelope on CO86 just outside of Kiowa and still limped home to Parker. so in short how "sensitive " are the newer diesel Mercedes ? and what do i need to look for if i am getting a used one? also any input on the BMW Diesels, I’ve heard mixed things about them.thanks
yes i know i am asking two different questions at the same time… so I am looking for input on both the Mercedes Benz Diesel and the BMW Diesel cars.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [December 10, 2015, 4:25am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/2 "2015-12-10T04:25:08Z")
Blue-tech a a Urea injection system to reduce NOx emissions.
If you don’t refill it, the car won’t start after awhile.
Besides which, you would be a polluting d-bag.
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### Author:  [@Nightaudit](https://boards.straightdope.com/u/Nightaudit)
#### Post date: [December 10, 2015, 4:57am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/3 "2015-12-10T04:57:47Z")
how bad of a dbag? old school diesel prechamber dbag? or VW emissions system cheat dbag?
Urea? so can i pee into the refill?
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### Author:  [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)
#### Post date: [December 10, 2015, 5:06am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/4 "2015-12-10T05:06:34Z")
> [@Nightaudit](#):
>
> how bad of a dbag? old school diesel prechamber dbag? or VW emissions system cheat dbag?
> Urea? so can i pee into the refill?
Not quite the level of dbaggetry as the coal roller dbags certainly…
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### Author:  [@Nightaudit](https://boards.straightdope.com/u/Nightaudit)
#### Post date: [December 10, 2015, 5:13am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/5 "2015-12-10T05:13:16Z")
OK what I’m really after is the " avoid this car like the plague because…(insert horror story here) or yes this is the best thing UNTERTÜRKHEIM or MUNICH has made in the last 20 years…Just be aware that … will break at 80K miles .
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### Author:  [@Nightaudit](https://boards.straightdope.com/u/Nightaudit)
#### Post date: [December 10, 2015, 5:19am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/6 "2015-12-10T05:19:43Z")
my neighbor (2 miles down the road) has a dodge ram that smokes like an **Тепловоз 2ТЭ116…**
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### Author:  [@Nightaudit](https://boards.straightdope.com/u/Nightaudit)
#### Post date: [December 10, 2015, 5:23am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/7 "2015-12-10T05:23:47Z")
yes it “coal rolls” in a way that “Soviet Russia” could love.
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### Author:  [@bob\_2](https://boards.straightdope.com/u/bob_2)
#### Post date: [December 10, 2015, 10:53am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/8 "2015-12-10T10:53:10Z")
> [@Nightaudit](#):
>
> Urea? so can i pee into the refill?
No you can’t
> [@](#):
>
> AdBlue solution has a far higher concentration of urea–32.5%–mixed into deionized water. That’s eight to 16 times the strength of your own urine, which also brings with it various salts, toxins, bile pigments, hormones, and roughly 95 percent water.
>
> Sensors in the urea tank monitor the concentration of urea. If you put in the wrong stuff, from pure water to windshield washer fluid to human urine, the car won’t run.
>
> Drat. There goes our consumer tip for the week.
> [http://www.greencarreports.com/news/1042727\_adding-urea-to-clean-diesel-cars-can-i-just-pee-in-the-tank](http://www.greencarreports.com/news/1042727_adding-urea-to-clean-diesel-cars-can-i-just-pee-in-the-tank)
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### Author:  [@kferr](https://boards.straightdope.com/u/kferr)
#### Post date: [December 10, 2015, 11:26am UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/9 "2015-12-10T11:26:51Z")
For your second question - I’ve got a 7 year old BMW 120d and have no problems at all. OK, it only has 35000 miles on it, but I have friends with far higher mileage BMW diesels that haven’t had any problems either. On a steady motorway run I can cruise at 75-80 mph and get 50mpg.
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### Author:  [@bob\_2](https://boards.straightdope.com/u/bob_2)
#### Post date: [December 10, 2015, 12:05pm UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/10 "2015-12-10T12:05:03Z")
Anecdotal evidence (in the UK) suggests that current German luxury cars are not as well made today as they were 8 or 10 years ago.
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### Author:  [@jz78817](https://boards.straightdope.com/u/jz78817)
#### Post date: [December 10, 2015, 12:38pm UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/11 "2015-12-10T12:38:41Z")
Never own a German car without a warranty.
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### Author:  [@Philliam](https://boards.straightdope.com/u/Philliam)
#### Post date: [December 11, 2015, 5:45pm UTC](https://boards.straightdope.com/t/mercedes-benz-blue-tech/740044/12 "2015-12-11T17:45:30Z")
Not always… my '96 S420 has required no more than oil change / wipers / one tail-light bulb in 2 years of ownership.
Does have an obvious flaw - much more attuned to 85-95 on the freeway than trundling along at 70. Definitely made for the Autobahn. 😃