Motors, MPG, and Reliability

Vinnie T · Apr 2, 2010

I've been looking at buying a Semi

Things have changed since I did this a few years ago, before all we had were mostly Detroits, CATS, and Cummins. All motors hovered around 5-7 MPG I would say on average. Some better then other for some things, Detroits get better MPG but leak oil..Cummins drink the fuel a bit more..CATS seem like they cost a little more to fix when they goto the mechanic. Of course these are generalities. Now I read about these newer motors that get better MPG, but I wonder with all these computers in them now a days they must be a fortune to fix at the mechanic and you need to be a rocket scientist to fix them.

So with all that said, what modern motors are reliable, get good MPG, have good power and hopefully are not too difficult and expensive to fix IYO?

greg334 · Apr 2, 2010

If I was going to get a new truck today, I would get a Detroit Diesel in it.

The computer systems are actually better than the mechanical pumps. There is a lot more that can be done with the newer engines that were impossible to do with the old ones. Even the one I am driving, with the older technology, it is easier to drive then the older mechanical system trucks.

The repairs are easier, the tech now can see what's going on easier than before but again it always depends on the skills of the guy with that shiny wrench.

Vinnie T · Apr 2, 2010

Any idea what the MPG is with the newer Detroits? And you say newer..Im looking at 05's right now. You are correct that they can just plug these trucks into the computers now a days and find out whats wrong. My last truck had a N14 Redtop, just about anyone could work on that motor. Seems the newer motors you are stuck paying 100.00 an hour at the big dealers to get your stuff fixed.

greg334 · Apr 2, 2010

I know one guy who had a DD60 in his 06 truck, he was hauling a reefer behind it and I remember he was telling me once he had it all figured out (sweet spot, etc... ), he averaged 7 to 7.3

highway star · Apr 3, 2010

I'm with Greg. The Series 60 has earned an awesome reputation. Fuel mileage, reasonable price on parts, and from what I've heard I think they don't leak oil more often than any of the others. Detroits were terrible for oil leaks back in the 2-stroke days and that reputation seems to hang on.

Vinnie T · Apr 8, 2010

How are they 12.7 liter 60 series? I heard they get a little better MPG

timexlgx · Apr 15, 2010

DDC60 is no longer produced, it has been replaced with new Mercedes/Detroit version DD15.
None of the new "bluetek" engines are worth discussion. They all suck. SCR, EGR or whatever is plain wrong for any internal combustion engine. Forcing exhaust, thus junk, back into cylinders makes no sense. It is plain wrong, thus SCR/EGR frequent failures, bad fuel consumption, injectors failures, engine temp, ........
We have tried all of them, none is working!!!
ISX seems to be up there, DD15 behind it.
Volvo engines are plain waist of money!!!!
With CAT out there are two more choices. Navistar and Mack.
Mack is 70% Volvo, and Navistar put together an engine from CAT, MAN and DAF. CAT engine block with european components. Who is going to fix that!?!?!??!? No one can fix Volvo engines, nevertheless CAT/MAN,DAF marriage.
So the obvious choice is Cummins ISX.
On ISX one can expect EGR valve failures every 150k, some injector replacement and turbos failing @/about 250k. MPG on 500-530HP engines 5.6-6MPG.
It is not true that these new engines get better MPG. Plain wrong.

layoutshooter · Apr 15, 2010

What do you really think?

We average 10.5mpg and have got as high as 12.7 MBE 450hp

Vinnie T · Apr 15, 2010

timexlgx said:
DDC60 is no longer produced, it has been replaced with new Mercedes/Detroit version DD15.
None of the new "bluetek" engines are worth discussion. They all suck. SCR, EGR or whatever is plain wrong for any internal combustion engine. Forcing exhaust, thus junk, back into cylinders makes no sense. It is plain wrong, thus SCR/EGR frequent failures, bad fuel consumption, injectors failures, engine temp, ........
We have tried all of them, none is working!!!
ISX seems to be up there, DD15 behind it.
Volvo engines are plain waist of money!!!!
With CAT out there are two more choices. Navistar and Mack.
Mack is 70% Volvo, and Navistar put together an engine from CAT, MAN and DAF. CAT engine block with european components. Who is going to fix that!?!?!??!? No one can fix Volvo engines, nevertheless CAT/MAN,DAF marriage.
So the obvious choice is Cummins ISX.
On ISX one can expect EGR valve failures every 150k, some injector replacement and turbos failing @/about 250k. MPG on 500-530HP engines 5.6-6MPG.
It is not true that these new engines get better MPG. Plain wrong.

Appreciate your input

I found out it is not manufactured, but heard it gets slight better MPG then the 14 liter Detroits, reliable, easy to fix too from what I understand.

bayouhotshot · Apr 19, 2010

layoutshooter said:
What do you really think? We average 10.5mpg and have got as high as 12.7 MBE 450hp

what

i have never seen anything over 8mpg................... my truck has the 425hp 10speed 373 rear on 22.5s at 65mpg it turns 1,500rpm this last IFTA report was 6.7mpg and thats being grossed at 54,999

layoutshooter · Apr 19, 2010

bayouhotshot said:
whati have never seen anything over 8mpg................... my truck has the 425hp 10speed 373 rear on 22.5s at 65mpg it turns 1,500rpm this last IFTA report was 6.7mpg and thats being grossed at 54,999

We have a MBE450hp, 3:58 rear end, 22.5s. We seldom run as fast as 65. We tend to run in the 57-62mph range. We are grossed at 48,000. We have an EatonFuller 10sp auto-shift, 3 pedal model. We like to keep the rpm range between 1200-1400, no higher. 1375 or so is 62mph for our truck.

Refer Hauler · Apr 21, 2010

I have had both the ISX and the DD60's. both performed very well and fuel mileage was above 6.4 on both engines at all times. What ever you buy make sure it is pre 07 engine the new emissions that took effect on 08 engines have affected reliability and fuel mileage. I would not buy a Cat for a number of reasons too numerous to mention here.

LDB · Apr 21, 2010

My last truck had the MBE450, also geared for about 1375rpm at 62-63mph. It had the 2 pedal autoshift 10 speed. I put the slotted mudflaps on the truck. I removed the windshield visor. I never floored it even though it was a really slow accelerating truck. I would easily get 10-10.2mpg empty and 9.x depending on load weight.