Today I drove 150 miles each way to Harrisburg, PA and every time I looked my speedo was at 85 or so.. and let me tell you the car never ran better!!

I did about 410 miles today (still have about 2 gallons of fuel left in the tank) and the car feels like a new one! These cars LOVE highways at high speeds. I'm not sure what it does, but it is definately good!!

My transmission is like 100% now since a fluid and filter change and about 2000 miles. Every trip it gets better and better.. AMAZING!!

John

How true John!

These cars really like to WORK! Ive never owned a car that just loves to be worked so hard, and it just seems to love a nice hard highway trip.
They hate to be started in the cold, but run so nice and steady when warmed up to operating temp.
This most certainly will not be my last MB diesel, love it when one of my friends gets in for the 1st time and says, "Is this a diesel?", and "i love these!"

Keep those MB diesels goin!!!!

Throughout the nineties I was traveling four states, and driving 60,000 to 70,000 miles per year. Much of that time was spent in my 240D. It was very common to crank it up in wee hours and drive 4 or 5 hours for an 8:30 or 9:00AM meeting. It was not uncommon to drive it 7 or 8 hours and stopping for nothing but fuel and a sandwich. Even though it was not a turbo five cylinder, it still cruised at 75 or 80 like there was nothing to it.

At that time my livelihood depended upon being where I said I was going to be and I can remember only once not being there because of the trusty old 123.

Even though I feel that all the later C and E Class cars; the 124, 210 and 203 are much better driving and handling cars, there is still something about a 123 that makes you feel good when driving it.

High mileage does not make these cars drive any differently. The last time I drove my 240D, it felt just like it did the first time I drove it some half million miles earlier. IMHO, the 123 MUST be one of the very best cars for it's time ever built.

Have a great day,

OK, I agree with the general idea but I share the opinion of John Wrizley (who buys/fixes/sells quality used mercedes autuomobiles and has his own web-site) that the life of any car is greatly impacted by the manner in which it is driven. Going fast on the interstate may be a good thing....for sure once in awhile.... but city driving is another matter. Hard, short accelleration followed by hard stops just punishes machinery.

I try to not get in peoples way but I also try to treat my car gently. Sometimes I have to push it but that is the exception, not the rule. I don't stand on the brakes and I don't max out shift points without a good reason. I do wind the engine up in smooth accelerations runs regularly (like on-ramps) but never go to the redline.

I apply this theory to all my many machines (boats, lawnmowers, motorcycles, etc.) and it works for me.

Nic
'85 300CD @ 145k miles

I agree with you all, especially Nic. I believe in easy warm ups, them put em to work. What amazes me is how these cars stay so tight. I believe in american products, but we still dont match german durability and longivity with automobiles.
I maintain a fleet of four military style SUS VEE's which use the 952 mercedes diesels with their 4speed automatics. They are a track machine with two drive units in tandem that articulate in the center for steering. These engines run in the 4800-5200 rpm range all day and just keep coming back for more. The transmissions are excellent. These babies work hard. Only enemy is heat. Overheat em and you have cracked heads.

The weekend is here!!!!!!!!!!

I agree with NIC in general regarding high RPM's ruining engines. There is a huge difference in running often at the red line vs. only rarely running the engine to the red line, even stopping 10% short of the red line will have a significant difference in engine life.

With the little diesels, there is another element involved. The engines make a limited amount of power while being built as strong or stronger than other more powerful engines. This, I believe, adds greatly to the longevity of the engines.

Have a great day,

Diesels tend to collect soot in the internals when driven at low load because the fuel won't burn well -- the fuel delivery is short, so the temp in the cylinder drops fast. Notorious for all sorts of ills at idle that dissappear as soon as you get some rpms.

Turbos are especially bad, as the turbine gets coated with soot and loses speed. Get it good and hot, and it cleans up, the valves polish a bit, the deposits in the cylindes go away, the carbon gets flushed out of the rings so they spin again, the compression comes up, etc.

Soot collection can be collosal -- my Volvo had IP problems, turbo problems, and EGR problems when I got it, so when I fixed the IP and took a long trip at night, I blew big chunks of burning carbon out the tailpipe on downgrades. Very impressive (ruined the exhaust, though) -- I guess the heat on the upgrades set the carbon deposits (about half an inch thick in the mufflers) on fire, and when I topped a hill and the fuel dropped off, the deposits burned enough to lift off and fly. Quite a sight!

Critical linear velocity for cylinder wear it 2500 ft/sec, when the oil film will break down. Rpm and stroke determine when this speed is reached. Otherwise, bearings never get going this fast in diesels, so won't wear as long as there is sufficient oil pressure. MB does a great job of matching materials, and you can drive them hard at high rpm forever so long as they run at normal engine temps and have good oil. Oil is critical....

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I agree with Peter. High temps and heavy load are critical to keep the engine clean - a clean engine is a happy one.

MB diesels are engineered such that their maximum speed IS their maximum sustainable speed. The governor will not allow the rpms to get to a level that would cause significant damage.

I have similar conversations with inexperienced MB owners who express concern over the engine temp exceeding 100 degrees C. As long as you don't get to the red zone, you are safe - the engine is designed to operate in the broad temp range.

This methodology is very different than other auto manufacturers.

__________________
Chris

'04 ML500 - 53k, Inspiration Edition, Desert Silver
'11 Audi A4 Avant - Brilliant Black
'87 300SDL sold
'99 C280 Sport sold
'85 190E 2.3 sold

psfred makes a great point regarding soot. This is why Universal grade oils, which are designed for diesels do a much better job of helping these engines live a long life.

The additive package is designed to disperse the soot and minimize it's ill effects. I'm not trying to sell any one brand, there are many that will help your diesel live a long life. The most common are: Chevron Delo 400, Mobil Delvac, Mobil Delvac One and Shell Rotella T. Any of these oils will do a better job in your diesel to combat the problems psfred describes, better than a regular oil with a "C" rating.

Have a great day,

Larry

What did you do for a living that you did 60-70K/yr?

John

John,

All through the nineties I was a Regional Manager for one automation software company, then Area Manager for a competing company covering the same four states. Many of the places I had to visit in Arkansas, Oklahoma, Louisiana and West Texas were not near airports, it was more efficient to drive the territory.

The size and type territory, coupled with the fact that I live in the boondocks, 117 miles from DFW airport makes for lots of driving.

Many people thought of this as something akin to a prison sentence, but for someone who likes to drive, like myself, coupled with having a pleasant car to do the driving in, made this an advantage, not a prison sentence.

In early '96 I gave my 240D to my son to drive (he had just turned 16) and bought myself a new E300, w210 car. I drove it a few years then found my five speed 300E. Once my son went off to the University of Texas, I reclaimed the 240D. When I started back in engineering in November '99, I drove it daily until the engine gave out. I got the parts car at that time and put the engine from it into the 240D. It laid down a little later and I went back to the 300E for a daily driver. I hope to put the 240D back on the road in the coming months and give the 300E a rest for a while.

Our company is on the edge, and the attack on the WTC hasn't helped us any. We are taking a pay cut and possibly will even go down the tube, so I may end up selling the new car and be left with the 240D and 300E for transportation.

I know this was more than an answer to your question, but once I get started I can't stop. Sorry.

Have a great day,

Following this thread waiting to see my question pop up, but it hasn't. My 82 300 td goes great on the highway, all day long 75-85. Loves it. But when I get off into town, it suddenly goes dead. it barely idles, foot to the floor, and the solution that works is to pull into a parking lot, shut it off for 5 minutes and then start it again. It then runs a little rough, but will accelerate and drive okay. It's like it's either starving for fuel (but how did it go 75-80 if that's the case?) or somebody unhooked the accelerator linkage. Really weird. Doesn't happen if I drive under 55 or just a short distance at any speed. Only after prolonged high speed cruising. Any ideas? I've changed all filters, new injector nozzles. Car has 450k on it, always MB serviced until last year. Thanks!
-pyro

Pyro:

Maybe a plugged tank vent? Algae? Usually algae will cause a serious loss of power, but vacuum in the tank (or possibly bad suction side hoses) can result in fuel starvation at idle, when the feed pump isn't going very fast. Try taking the fuel tank cap off after a hard run and see if air sucks into the tank. If so, the vent line is plugged -- hard to find, it's under the car somewhere near the rear suspension.

It is also possible that you have a bunch of junk in the tank that packs down on the "sock" filter in the tank at speed, and falls back off when you shut the car off.

Peter

__________________
1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

There is another active thread that I am repeating this from - it is someone else's idea, but it sounds like it could possibly be your problem, and its easy to test.

Perhaps your fuel tank cap is not vented properly - that is, the vent hole is plugged. Should be easy to test. Next time you pull off the highway from a high-speed run, jump out and take off the "gas" cap. If it runs properly immediately after taking off the tank cap, the vent must really be blocked.

Would be interested to know if this turns out to be your problem.

Ken300D

I think Peter's comment is more accurate than mine. I doubt if the cap itself is vented. I think there is a vent tube in the top of the tank that runs down under the car. It might be pinched or blocked.

However, the test of removing the fuel tank cap will quickly vent the tank and allow you to observe the results. A very cheap test to run first.....

Ken300D