Older is better?

vtdog · **Joined:** Fri Sep 30, 2005 11:27 am **Posts:** 640

I now have about 70k miles on my '05. I have to say that starting at about 60-65k it seems to me that the engine is running "better". There appears to be more power/acceleration/torque and my mpg has gone up by 1.5mpg. When I bought the Jeep new the "diesel specialist mechanic" at the dodge/jeep place told me that the car would not run really well unitl about 25k miles. He was right about that, but I have to defer to the gear heads in here about this.
Is it my imagination (hope?) that I am doing better now that the car is getting older? Do diesel engines take this long to break in? I don't remember this long a lag time for good performance in my '78 diesel rabbit and that is my only experience with diesels up to now.

geordi · **Posted:** Wed Sep 10, 2008 2:19 pm

You had a wabbit? Cool!

I'll second your experiences. My TDI Jetta had 5100 miles on it when I bought it. When I sold it, it had 150k on it. In between, up until about 50k or so, I couldn't get it to give me any more than 40mpg, and a low of 30 when I was BEATING on it for a tank. Somewhere above 50k, it started consistently returning 38-40 under normal driving (which was "sporty" for me) and a whopping 48mpg for one tank that I babied it!

This was on the AUTOMATIC transmission too, so I had one less gear and a weaker OD than the stick guys claiming 50+ mpg all the time.

I think our "light-duty" diesels DO take that long to break in, b/c the engine isn't being placed under the heavy stress all the time of a class 8 or even a 1-ton that is used for heavy hauling.

bugnout · **Posted:** Wed Sep 10, 2008 2:48 pm

I just turned over 60k and did the second transmission service. My CRD is definitely getting better as it gets older. Haven't noticed an increase in mpg yet.

moto-scoot · **Posted:** Wed Sep 10, 2008 10:33 pm

75k.... Just got in from trip pittsburgh to kill devil falls NC,
& back buy way of west virgina 32 mpg [evic]
home overnite then to phili & back pulling trailer 70 mph
on turnpike 23mpg

retmil46 · **Posted:** Thu Sep 11, 2008 3:03 am

It does seem to be the nature of the beast - I've heard this same advice about diesels in general repeated many times over the years.

Another data point - my '87 MB was rated 25/30 when new under the old EPA system. Now, 20 years old and 149K miles, it'll knock down 35 mpg combined without even thinking about it - with an old fashioned non-electronic non-lockup slushbox auto no less.

Bonehead · **Posted:** Sun Sep 21, 2008 3:22 am

97K on mine and the mileage is still getting better little by little

dgeist · **Posted:** Sun Sep 21, 2008 8:29 am

moto-scoot wrote:

75k.... Just got in from trip pittsburgh to kill devil falls NC,
& back buy way of west virgina 32 mpg [evic]
home overnite then to phili & back pulling trailer 70 mph
on turnpike 23mpg

I'm just impressed you can go 70 on the PA turnpike

Perhaps PennDOT learned how to pave since I moved south in 1990...

geordi · **Posted:** Sun Sep 21, 2008 12:03 pm

retmil46 wrote:

It does seem to be the nature of the beast - I've heard this same advice about diesels in general repeated many times over the years.

Another data point - my '87 MB was rated 25/30 when new under the old EPA system. Now, 20 years old and 149K miles, it'll knock down 35 mpg combined without even thinking about it - with an old fashioned non-electronic non-lockup slushbox auto no less.

Think about what that could do with another OD gear, and a lockup converter... :shock:

Kinda sucks all the wind out of the "heavy cars can't get good mileage" argument from the auto industry, hmm?

retmil46 · **Posted:** Sun Sep 21, 2008 7:48 pm

geordi wrote:

Think about what that could do with another OD gear, and a lockup converter... :shock:

Kinda sucks all the wind out of the "heavy cars can't get good mileage" argument from the auto industry, hmm?

Believe me, I spent some serious time looking for a tranny option with at least an OD gear. MB did put out a 5 speed version of this tranny, the 722.5, in the early 90's - basically the same tranny with an OD gear stuck on the back. But from what I've heard from my tranny guru and the MB crowd the 722.5 tended to be as mechanically reliable as a DC torque converter. :wink:

I even looked at a GearVendors remote mount unit stuck where the center bearing is for the driveshaft. But there ain't enough room to cuss a cat in that shaft tunnel.

I had to settle for overhauling the old tranny and going with a size larger tires - and even that made near a 5 mpg difference.

geordi · **Posted:** Sun Sep 21, 2008 11:48 pm

What about a lockup converter? I'm sure that someplace like SunCoast could fab something up. With all the old oil Benz cars still on the road, there is a HUGE market for a locking TC. Who knows, they might have already done it. I'm not up on the old MB line, b/c I don't own one.

retmil46 · **Posted:** Mon Sep 22, 2008 11:33 am

geordi wrote:

What about a lockup converter? I'm sure that someplace like SunCoast could fab something up. With all the old oil Benz cars still on the road, there is a HUGE market for a locking TC. Who knows, they might have already done it. I'm not up on the old MB line, b/c I don't own one.

Like I've said, I've looked high and low, but nada. You'd need a tranny (or some heavy modifications) with the hydraulic and control circuits to be able to make use of a lockup torque converter.

Some aftermarket tranny shops do offer a lockup conversion kit for the older GM autos, but that's about it.

Anything above and beyond swapping in a MB 722.5 tranny gets into some serious money - like enough to buy a second used MB diesel.

Older is better?

Who is online