# City Driving and Diesels



## AutoUnion (Apr 11, 2005)

Axel61 said:


> Im with the guys here YOU HAVE to AIR out the diesel from time to time. i live in Puerto Rico and I do most of driving in the CITY cause we have so much traffic and I do let the beast out everyday cause of the side eefects of pampering diesels.


This.

Diesel has to be taken out on the highway every so often to let the DPF burn off the soot


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## Snipe656 (Oct 22, 2009)

I have had plenty of DPF burn offs during city driving. No need to specifically get on the freeway for that. Now I'd agree with that of city driving equals less than 2 miles per trip but heck I'd then question why even drive anything


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## DieselAlles (Apr 14, 2012)

My experience relates more to agricultural/class 8 truck engines but it would generally apply to all engines. Not allowing an engine to reach its operating temperature has an impact on the life of its components. Acids formed during the combustion process will form on cylinder walls, rings, etc and etch away minute amounts of metal if not allowed to burn away. Studies have shown this is where the majority of wear happens. These acids will then combine with the oil to contaminate it further, which is why a lot of manuals specify shortened oil change intervals with this type of operation. Exhaust components not allowed to get hot enough will have a shortened life expectancy because acid and water will condense on the inside and start the oxidation process. There is also the problem called "wet stacking" in diesels. When a diesel is allowed to operate well below normal operating temps, unburned diesel fuel can accumulate and get past the pistons to dilute the motor oil. It also can be blown out of the exhaust and on farm equipment shows up as a black ooze coming out of the exhaust. This is why many makers of diesel engines build in an automatic fast idle to keep the engine hot to combat wet stacking.


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## Snipe656 (Oct 22, 2009)

My truck has a very distinctive fast idle feature. It only happens though if left in park and turns off as soon as your foot touches the brake. I believe only happens in cold weather an it sounds like it loads up the motor. If I just feather te throttle up and hold a high idle it sounds different. I never have noticed a fast idle in the BMW, do they also have this though?


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## dThree35 (Mar 23, 2012)

Snipe? Houston? Walk? Sweat? Need shower upon arriving to work? 



Snipe656 said:


> I have had plenty of DPF burn offs during city driving. No need to specifically get on the freeway for that. Now I'd agree with that of city driving equals less than 2 miles per trip but heck I'd then question why even drive anything


Sent from my Galaxy Nexus using Bimmer App


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## Snipe656 (Oct 22, 2009)

I usually take a 2-3 mile walk every day at lunch. Of course not in the summer months which hit us soon.


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## dThree35 (Mar 23, 2012)

I was wondering how long before someone called me out on my short commute!



Snipe656 said:


> I usually take a 2-3 mile walk every day at lunch. Of course not in the summer months which hit us soon.


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## Snipe656 (Oct 22, 2009)

I am just jealous of your commute.


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## DieselAlles (Apr 14, 2012)

I'm not sure about the BMW diesels and if they have fast idle. My 2001 Ford Powerstroke came with the feature. My brother-in-law's Duramax has it as well. My John Deere of 2007 vintage or older tractors don't have it. Not sure about the newer tractors. Also, our 2003 VW Jetta TDI doesn't have the feature. On our class 8 trucks, the Freightliner equipped with a Cummins N14 has a similar feature but the Volvo tractor with a Detroit Diesel series 60 doesn't.


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## DieselAlles (Apr 14, 2012)

My commute used to be 60 miles round trip. In the 2003 VW TDI, that was one gallon of fuel. Two quarts there, two quarts back. Now my commute is from the kitchen to my office. I kinda miss the challenge of bettering my average but I don't miss the traffic.


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## rmorin49 (Jan 7, 2007)

DieselAlles said:


> My commute used to be 60 miles round trip. In the 2003 VW TDI, that was one gallon of fuel. Two quarts there, two quarts back. Now my commute is from the kitchen to my office. I kinda miss the challenge of bettering my average but I don't miss the traffic.


Funny, my commute is the same length and I am about ready to eliminate it as I am now retirement eligible for the second time. Life is too short and I need to start living more so we are leaving today for 3 weeks in Europe.:thumbup:


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