Community Forums

tuffr2 · 05-28-2013, 04:17 PM

I have heard that a diesel engine will have more power and get better mpg after it breaks in. Anyone can give me an idea of how many miles is needed before the engine hits it peak?

CampDaven · 05-28-2013, 04:26 PM

I'm sure they vary by mfg. 17K on my Maxxforce V8 and still gaining torque.

jesilvas · 05-28-2013, 05:35 PM

You always read this, but no one ever says why.

SmokeyWren · 05-28-2013, 07:18 PM

Generally, under ideal break-in conditions and maintenance, it takes about 10,000 to 15,000 miles to fully break in a new diesel engine. Fully broken in means you no longer get better and better MPG, and you no longer get increased power and torque as the miles accumulate.

But if you don't work the engine hard and get it hotter than a two dollar pistol frequently and for long miles, then it can take as long as 30,000 miles to fully break in.

And if you use it as a commuter car and never work it hard, it will never be fully broken in.

Here is an old but excellent article on the topic:
TheDieselStop.Com - Breaking in a diesel engine

336muffin · 05-28-2013, 07:32 PM

When I was a Owner-Operator I had my Cat Inframed at 520,000 miles. They would not turn the fuel past factory specs due to warranty until I had put 50,000 miles on it after the rebuild. They then gave me 10% more, 25,000 after that they gave me another 10%. I did not ask for more than that because I didn't need any more torque. Kept it until 978,000 with no problems till I sold it.

Mr_D · 05-28-2013, 07:39 PM

I don't know, never kept one long enough to find out. Only up to 39,000 now on the '02 ISC.

onechaddude · 05-28-2013, 09:00 PM

A Cummins rep told me isb in dodge truck not broken in til 75,000 miles. I have had probably 15 of them and all would get better mileage and had more power in the 15-20,000 range.
Chad

azdryheat · 05-29-2013, 12:03 PM

All Chevy says is not to tow for the first 500 miles. Guess it's broken in at that point.

onechaddude · 05-29-2013, 12:27 PM

Quote:

Originally Posted by azdryheat

All Chevy says is not to tow for the first 500 miles. Guess it's broken in at that point.

Ram says the same thing. Mechanic said the 500 miles were for the rear end gears to seat without additional pressure on them. Think about it, motorhomes are loaded from the get go so? My brother did tow with a new Chevy couple years ago with only 200 miles on it. When truck had less than 3000 miles, had to take it back for new seals in the rear axle. Mechanic said you towed when truck was new didn't you. If course he said "no way".
Chad

jwyoming · 05-29-2013, 12:58 PM

We have thirty diesel in our fleet and it is a fallacy that the new diesel engines need a break in. They are good to go from the onset. Tjhey do need to be run everyday or you will develope problems

Dave1956 · 05-29-2013, 03:03 PM

Not certain what you are asking! Follow your manual before towing heavy. My 2004 Dodge Ram Cummins Diesel performed much better after about 50K. As of today it has 198K on it and I have had no issues. I get 23 mpg when not towing (mostly hwy) and about 14-16 mpg towing 8000# at about 63 mph.

I have not noticed any difference in performance since about the 50K mark. I really cant describe it, but I got a sense that it was just running better. At 100K I went to Mobil One synthetic and started sending samples in for testing.

I hope to get another 100K out of it at the minimum.

Dave

tuffr2 · 05-30-2013, 12:42 PM

I got my answer from Smokey's link. Thanks Smokey. I had a new diesel now with 7,400 miles. The 1st 1000 miles no towing. Since then it tows a small runabout at 2,700 lbs. A TT at 7,000 lbs and a 5er at 14,000 lbs.

okdallas · 05-30-2013, 03:37 PM

If you guys were going to buy a used Diesel with aprox 100,000 mi what would be your chose for a 3/4 ton to pull a 5er or a TT?

jamesrxx951 · 05-30-2013, 03:51 PM

Quote:

Originally Posted by onechaddude

Ram says the same thing. Mechanic said the 500 miles were for the rear end gears to seat without additional pressure on them. Think about it, motorhomes are loaded from the get go so? My brother did tow with a new Chevy couple years ago with only 200 miles on it. When truck had less than 3000 miles, had to take it back for new seals in the rear axle. Mechanic said you towed when truck was new didn't you. If course he said "no way".
Chad

My understanding of the no towing for 500 miles is more for allowing the brakes to seat into the rotors. Never heard of breaking in a rear end (especially the seals) and it seems more of an old wifes tale. When new brakes are installed, they should be seated in before towing first.