Last post on Aug 27, 2012 at 10:06 AM
You are in the Diesels
What is this discussion about?
Ford F-250 Super Duty, Dodge Ram Pickup 2500, Chevrolet Silverado 3500, Diesel, Truck
#94 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [firewalkerjohn]
Feb 22, 2008 (11:06 pm)
Hi John, If your truck does like mine your mileage should continue to improve for several thousand more miles. These engines are built with tight ring tolerances and take a while to break in. Also my driving is probably 75% rural 25% city and I drive consertive to get more mileage. I have also found that speed realy affects mileage. The other day on a long stretch of rural road I decided to experiment with mileage and speed. Using the mileage computer I dropped down to around 50 mph for about 5 to six miles and was showing around 24 mpg, 55 gave me 22 mpg, 60 gave me 20.5 and 65 was 19.3. Now I have never gotten as good of mileage as the computer shows when I calculate miles by gallons but I figured this would give me some ideal how much speed would effect mileage. Also I noticed that steep hills really effective mileage also. These are very heavy trucks. Mine weighs 7980 lbs empty with a full tank of fuel, so the amount of start and stops and hills will really affect individual mileage results. The price of diesel is hurting all of us but I,m still enjoying my truck. A couple of other things to watch is air pressure in tires I keep mine at 65 psig this is 18 inch rims and keep a check on the fuel water seperater. I do think you will see a 2 to 3 mpg improvement as you get more miles on your truck. Hope this info helps a little , will email you later. Thanks Frank
#95 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [diehardford]
Apr 12, 2008 (1:31 pm)
does your '08 warm up in the 5 to 10 minutes that you let it warm up. I am in the St. Louis area and my truck will not warm up when I first start it at home with my auto start. I have to be 10 miles down the road before it start blowing warm air. When it gets really cold I have to take it out on the highway to get it to warm up. Not to sure if this is normal for other 08 diesels or not. My '05 diesel that I traded in warmed up much quicker.
Any info about your warm up time would be thankful
#96 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [firewalkerjohn]
Apr 12, 2008 (4:39 pm)
I thought that not warming up at idle was a feature of almost all diesel engines. The diesel cycle allows such a lean burn that at minimum idle the engine simply does not make enough waste heat to keep the engine warm.
I believe that some diesel engines can actually experience excess engine wear to the point of damage, if run at idle for an extended period--maybe an hour or two. The Mercedes inline-5 cyl diesel engine used in the Sprinter van actually had an option called "high idle", which I presume would be used to keep the interior warm if it had to be idled for an extended period say with a sighseeing application, or caught in a traffic snarl.
So I don't think you should use a remote start to try to warm-up your diesel by idling it for 10 minutes. Start it up and drive away immediately. It would however, benefit from a block heater on a timer.
#97 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [jim314]
by KCRam@Edmunds HOST
Apr 13, 2008 (2:32 pm)
Totally correct. This is why tractor trailers cover their grilles in winter - it's the only way the radiator will maintain heat.
kcram - Pickups Host
#98 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [firewalkerjohn]
Apr 15, 2008 (12:43 pm)
John,Here in Rock Hill SC it does not get as cold as St Louis. 18 to mid 20s for lows is about as bad as it gets except maybe a week in January were we might see a couple of nights near 10 degrees. But letting the truck warm for about 5 to 10 minutes will clear the frost and ice off the windows . The air from the vents is warm but not hot and the temp gage will be in the lowest part of the normal range. It takes about a mile of driving for it to get fully warmed up to normal temp.
#99 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [diehardford]
Apr 15, 2008 (3:43 pm)
"Cummins Engine Co. states that it is three times harder on an engine when idling than pulling a load down the highway. It is much more economical to purchase a generator or a diesel-fired cab and engine heater than to idle your engine. Diesel engines are not built to be used as heaters."
The preceeding quote was in reference to large truck diesels, but Mercedes did offer an axiliary diesel fuel heater in their Sprinter van. Of course, it may in fact not be worth it to go to the trouble and expense of buying and installing a generator or diesel-fired cab and engine heater for the few days you might really need it. I am not familiar with these auxiliary heaters, their cost and maintenance issues.
#100 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [diehardford]
Apr 15, 2008 (5:03 pm)
Thanks alot for the info. May I ask again what year your your super duty diesel is? Also if you dont mind may I print your reply and use it in my arbitration case. I need to show Ford that my '08 is not functioning properly comparing to other '08's. Ford has since come back to me since starting the arbitration saying that my 5 check engine lights for low engine operating temperature warming problem is NOT a problem and my truck is run correctly. I do know that my 2005 6.0 diesel would warm up just as you explained your is warming up, and my '08 is just the opposite.
#101 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [firewalkerjohn]
Apr 18, 2008 (7:34 pm)
Hi John, My truck is a 2008 with the 6.4 diesel. Yesterday I took it to the dealer for a oil and fuel filter change. I spoke to the mechanic about letting the truck warm on cold mornings . His opinion was that its not a bad idea to let one warm up for a few minutes before driving off. He is one of two mechanics certified to work on the new 6.4 at this dealership. I don't mind you using my reply in your case. Do remember that the 6.4 has a total of 6 different radiators to keep things cool. The main radiator is about 20 percent larger than the one in the 06. So the 08 is naturally going to take longer to warm than the 06, but it should still warm up some. I will agree with some of the other post that a block heater in colder climates may not be a bad idea. They are not to hard to install and some will install in the radiator hose line. Several years back those were about 80 dollars, I have not priced one lately. Hope this helps Frank
#102 of 133 Re: 4x2 vs. 4x4 and F250 vs. F350 3.73 rear end [jim314]
Apr 18, 2008 (10:32 pm)
Ford does offer an auixilary cab heater and engine block heaters on their 08 trucks.Neither option was that much, I believe the cab heater was around 200 dollars and the engine block heater was around a 100 dollars. If I had done a factory order I would have got both options. however the main option I wanted was the in dash nav system and their were only 5 trucks within 200 miles of me with the nav and the color that I wanted and none of those had the cab heater or block heater. While I agree that letting a truck idle for 30 minutes to an hour is excessive I consider a five minute warm up in cold weather to be a normal warm up time. To not let it warm up enough to clear the windows is both illeagle and unsafe. While I haven't had experience working on truck diesels I have had experience working on standby diesel generators every thing from a 5 hp pull cord up to a 16 cylinder 8 turbo 10 thousand horse power unit with a 17 inch bore and 21 inch stroke that sips fuel at about 43 gallons per minute. Each of these were set to run at idle for 3 minutes to come to operating speed and temp before engaging load and after running under load each was set to run at least 10 minutes no load to cool down before shutting down. Ford recommends at least a 3 minute cool down on the 6.4 to cool the turbos after running under load. All of these engines would be 15 to 30 years old today so I can't say what a modern cummings engine would do but the ones i used to work on would generate heat and a lot of it at idle.
May 23, 2008 (11:14 am)
My '07 GMC Duramax w/ 15k miles gets a dismal 13.7 mpg max. It doesn't seem to matter if I am driving in town or on the highway. If I'm towing, it goes down to 11 mpg. That doesn't concern me as much as the absolutely awful gas mileage on average. My [now probably in Mexico because it was stolen] '03 F-250 got 18 mpg in town/22 hwy, so this was a bit of a shock. I waited not-so-patiently for the engine to get a few thousand miles on it, thinking the mpg would improve, but it hasn't. With diesel prices at this hour $4.59/gal. here in the SW part of NM, I would like any input on chips that might improve gas mileage. I'm not interested in more HP or torque. Am I dreaming?