break in for better mpg?

[JTreas]

i was wondering if anyone with a 3rd-gen has found out if working the engine helped with mpg's after a few miles? read that some 2nd gen guys that didn't have a trailer to tow put sand bags in the bed for some weight to lug around, would that work for the 3rd gen? and if so how much weight would be good? 500#, 800#?i read the manual about the engine not needing to be "broken" in but just thought i would ask guys that knew their trucks.

 

[mberry]

Yes it would help to put a larger load on the engine. If it were me, I would put in as much weight as I could and still be legal. Then again, I could find something to tow somewhere.



Also, I would not recommend switching to synthetic oil until you have at least 10K miles and it's probably better to go 20K. I switched too early. When I get some more miles on this Amsoil, I'm switching back to Delo-400 for about 10K miles.



All this is subjective also. It's your truck and you can do whatever you want with it. I'm just sharing my experience.



Mark.

 

[TimG]

Mark



Looking at your Sig. I see you have a PMCR, have you noticed any improvement in fuel mileage?



Tim

 

[bighornram]

i was wondering if anyone with a 3rd-gen has found out if working the engine helped with mpg's after a few miles? read that some 2nd gen guys that didn't have a trailer to tow put sand bags in the bed for some weight to lug around, would that work for the 3rd gen? and if so how much weight would be good? 500#, 800#?i read the manual about the engine not needing to be "broken" in but just thought i would ask guys that knew their trucks.

I have been following the proceedure outlined in this forum for break-in. I drove like it was a borrowed truck for the first 1000 miles, then following the owner's manual it states not to exceed 50 mph. for the first 500 miles towing. That has been hard to do but I logged the final slow miles this weekend and I can now drive it like it is stolen! Oo.

My next camping trip will be even more enjoyable since I will be able to at least go the speed limit. Mileage so far (during break-in) has been better than my 02' was by about 2-3 mpg's calculated.

 

[Bertram65]

My truck has gotten about the same mileage since it was new, which is around 15mpg average over 32k miles. I have towed quite a bit and never noticed any improvment after working it hard for several thousand miles. I cannot see what could cause enough friction that once broken in could effect mileage any significant amount.

 

[Vaughn MacKenzie]

I saw a comment by Cummins once to work the engine, but don't overdo it or get too carried away. Yes drive 'er easy the first several hundred miles then work it.



Now here are some tips I used for the very first couple hundred miles when I get my new trucks:



 Don't use cruise control at all or maintain a steady highway speed. Avoiding any length of highway driving is best. Vary the RPM regularly and use all the gears (driving around town is a good idea to use the full RPM range).

 Roll in and out of throttle, varying load. Do an occasional nearly-full throttle acceleration to highway speeds.

 Do not let it idle at stop lights or anytime. . . bring the RPM up and vary it while waiting for green, or shut it off if you pull in to stop for a couple minutes.





Vaughn

 

[Scooby]

I beleive the "go slow when you tow" (for the first 500 miles) is really to break in the differential.



Do what Vaughn listed above. If you want to really break it in 800 lbs of sand won't do it - your truck won't even notice it! With my '01 I actually rented a trailer and towed my SUV around since I was without a camper or other heavy toys at the time. I don't think the motor truly broke in until I took a cross-country trip with a 5000 lb Lance Camper and while towing a flat bed trailer with a highly modified Jeep.



My 04. 5 has only seen the Lance Camper and I think it still needs more break-in. (just turned 12K miles)

 

[bighornram]

Then RETURNED it

You are the breakin King.

 

[JTreas]

thanks gocargo, i wonder if my stock tires will handle that, door tag says 1900 total for the truck based on the tire info.

 

[jimnance]

I'm on my fifth CTD. Not because they are bad either!



After five trucks in fifteen years I can't say that the break in resulted in a significant improvement in fuel economy. Maybe one mile per gallon at most.



They importance in break in comes from achieving a good ring seal. To achieve this you need to work the engine hard to get the internal cylinder pressures up. This forces the rings more tightly against the cylinder wall. In this case you actually want to wear the rings into the cylinder. It produces a nice tight seal and helps with oil consumption as well as reducing crankcase pressure. I suppose taking it a bit easy the first few hundred miles is ok because that is when the most severe abrasion (read break in) is occuring. You get some extra heat then, and it's possible if you roar up hearbreak hill with 15K in tow at 3,000 RPM and ten miles on the odometer you might aneal the rings.



Anyway, After a couple of hundred miles hook up to a good load, 10K or so, and run her pretty hard. It's good for the engine.



I've never had enough oil come out of the breather tube to leave a spot in the driveway. Even with 100K plus on the odometer. That's because the engine was broken in right. I've seen some guys that complain about drips from the breather. In many cases it may be the result of improper break in. Most of the break in will happen in the first thousand miles or so, but continues for a few thousand miles. The use of synthetic is the kiss of death during break in. I'm not a big fan of them for cost reasons, but for certain don't use them during the first ten thousand miles.

 

[JStraw]

Here's the real deal from CUMMINS. There's more at play than engine break-in to get good mileage. Go here for the info:



http://www.everytime.cummins.com/every/misc/info.jsp

 

[jimnance]

Interesting stuff. I really didn't take enough time to see if Cummins feels that break in plays any role in fuel economy. However, it didn't make the top ten items in the summary. Some interesting pearls of wisdom from the article:



Above 55 mph, each 1 mph increase in vehicle speed decreases fuel economy by 0. 1 mpg.



The most efficient drivers get about 30% better fuel economy than the least efficient drivers.



[/I]Every 2% reduction in aerodynamic drag results in approximately 1% improvement in fuel economy.



[/I]Every 10 psi that a tire is underinflated reduces fuel economy by 1%.

 

[JStraw]

Thats what I noticed also. Appears that rolling resistance/ aerodynamics/ weight and drag are the top players in getting better fuel efficiency. I guess thats why the new big rigs have changed body shape, added skirting and other items to ease through the air barrier instead of plow through it using brute force.

 

[GCross]

Just read the Cummins MPG facts posted by Jeff, very informative. The big square rigs that I drove in the 70's and 80's probably featured the worst aerodynamics imaginable and we got 4MPG. But fuel was plentiful and only cost 20 - 30 cents a gallon so we were not very concerned. If modern trucks are getting 7MPG that's an improvement but certainly does not compensate for the current fuel price.



-George-

 

[jimnance]

Just read the Cummins MPG facts posted by Jeff, very informative. The big square rigs that I drove in the 70's and 80's probably featured the worst aerodynamics imaginable and we got 4MPH. But fuel was plentiful and only cost 20 - 30 cents a gallon so we were not very concerned. If modern trucks are getting 7MPG that's an improvement but certainly does not compensate for the current fuel price.



-George-

Unfortunately, I think we saw big truck fuel economy peak about in about 2002. When the big engine makers were forced by consent decree to meet the NOX emissions standards early, fuel economy suffered a lot. With the exception of CAT, I think the others resorted to cooled EGR and other fuel modifications to meet the needed emissions levels. This took us from a fleet average of 6. 6 to 6. 7 MPG down to 5. 8 to 5. 9 MPG. I'm hoping that ULSD and a catalytic system will help to restore some of the lost economy.



I'm sure the same is true to a lesser extent with 2004. 5 and later CTD's. They have to comply with the NOX rules. Though they found a way through tinkering with fuel timing, multiple pulse injection, etc. , I am sure fuel economy has suffered somewhat. Optimum combustion favors the formation of NOX so anything they did to meet the standards would likely reduce fuel economy.



This is one of the reasons I've considered the new Edge box. They are not burdended with meeting the emissions standards and can use settings that result in improved economy. Also, having the safety systems incorporated in the box is nice so you can help avoid abusing the engine. Extra power is a bonus, but not what I'm really looking for. I'm towing heavy, and I don't want to overly stress the 48RE.

 

[CPG]

These Cummins engines were not really designed for liitle old lady's to take to tea or knitting parties.

To be sure, there are other things on these trucks to be broken in other than the engine. I took it with common sense the first 500 miles and then loaded our 5vr on the back and took a long trip in the Sierra Nv. mountains. This really helps to seat the rings and other parts. These engines were made to work. If one uses common sense and does not show off in the hills, they will give long service. Long idling is about the worse thing one can do to a Diesel engine.