? on how to keep a daily driver lasting forever
 

Hi,

my 83 300D has 189K miles, working on 190 very soon. I drive it numerous times a week on ~10 mile trips, and then every weekend on 100 mile trips, so it gets pretty good use. My question is how to get it to last as long as possible. I know that the idea is to change the oil hot and often, but this leads me to my first question:
-If I drain it hot, it takes hours for the engine to cool down to even the point in which I can place my hand on it. How cool should it be before I add new oil to it, to minimize stress on engine components and on the new oil?

-If I do a lot of highway (High speed driving), will I use more oil due o higher RPMs, and Id assume more sloppy engine operation due to this?

-I know a highway mileage engine will last longer then one driven around town usually, but for an 83 300D for example, what is the best speed to drive? Will 75 subject the engine to too much stress and cignificantly reduce life? I know there probably are lifetiem tests liek this, and if anyone knows the general trend, Id love to know it. My car has done 95 MPH for a short burst, so Id think that 75 ius within its design speed range, so the engine should last well at this condition, but Im not sure.

-does adding high detergent fuel additives (I use shell rotella DFA every tank) hard on parts? I know if provides lubrication, but I dont know what the detergency might do to injector surface metal, etc.

-What level of smoke is acceptable? I noticed last weekend while up in the montains, and the temperature was below 60 that I could see a bit of smoke or condensate, or something else. I know when I floor it from a stoplight or something, with headlights behind me at night, I can leave quite a smoke cloud. However, smoke is minimal when cruising, even when looking at night with bright headlights behind me. I think I have some issue with my heaqd gasket, as I see a few oil spots in the coolant recovery bottle, but the coolant level doesnt go down, so I dont think Im vaporizing coolant to overboard in the cylinder...

Any help on these things would be appreciated. Thanks

JMH

JMH,

I've put 20,000 miles on my '84 300D turbo in the last 6 months. It'll turn over 254,000 ths week.

You don't need to wait until the engine cools off to add more oil. Thermal shock has never been an issue on any engine in my experience. The new oil will get plenty hot as soon as you start running the engine, so there's no need to worry about stressing it- that's what it was designed to handle.

In general terms, you have the potential to use more oil at highway speeds, but this engine has 2 things going for it-

1) a well-designed blowby recovery system, and
2) a huge oil supply (7 qts) compared to other 3-liter gas engines.

These Diesels like to be driven hard, and mine seems to find itself doing 75 at cruise speed with no problems, and oil consumption is about 1 qt every 2000 miles, even at 254k.

Just keep an eye on your engine temp and oil pressure, check oil level every time you fill up, and soon you'll get a pretty good idea of what your oil consumption is. You have one of the best automtive diesels EVER designed. Enjoy it!

Regarding smoke: I've heard from several diesel vetrans that a 'light whisp of smoke from the rearview mirror on a sunny day" it optimal. Anything less is even better, I always though, but I'm not sure on that one.

Also, gauging smoke amount at night is impossible - it always looks like you're losing massive amounts of unburnt fuel when in fact you are not. I'm not sure what the phenomenon is that causes this, but if you're only smoking a little during the day you're fine.

The great thing about these cars is that literaly chaging the oil hot and often, keeping the fuel filters fresh and valves adjusted, you've got a machine easily capable of 500K. Keep it washed (and clean body drains), to keep rust in check, and you're set!

Regards,
- Ryan

If you use the car on short trips and want it to last forever, consider an aux. oil pump to pre-lube before starting. With a diesel, it adds no additional delay to your trip, as the pump can operate while the plugs are glowing. These kits can adapt to an aux. oil filter, too, to keep the oil extra clean. Here is an example from a manufacturer--no affiliation, except they have been researched by members of my other forum:
http://www.enginelube.com/

Just an idea--I plan to do this when I put a new bottom end into my W115--if that ever happens. Cheers, Andrew Seidel.

OK, I've a little different viewpoint than some on this but...

I don't push my car hard. While I might rev it up entering a freeway once in awhile, I never drive really aggressively. I try to avoid bumps/potholes and hard transmission shifts. Also try to not stand on the brakes unless its just unavoidable. My motto is "easy does it".

I have many nice machines and this policy has served me well over the years. By the way I follow the same policy with my body and never use all my strength when lifting. Old machines and oldish people need to be gentled a bit.

Of course, I also follow a strict maintenance program including preventive maintenance on major components. Using synthetic oil has the small advantage of helping from cold start as apparently the synthetic stays up in the clyinder better than natural oils do.

Nic
'85 300CD @ 153k miles

I remember when my 240D's hit 200,000 miles I started wondering what I was going to do about the engine overhaul. The first one went another 80,000 miles. Then I got my second one and was determined to take much better care of it. When I started having that worry again, it went another 180,000 miles.

Change oil hot, often and look for what might be falling off while you're underneath.

Good luck,

That pre-oil pump idea is pretty good! Has anyone used one before? Or does anyone have them on an MB? I am pretty interested. What do they run for?

I'm with Larry on this one
 

At 60kmi, I was hopeful that it would go 100kmi.

At 100kmi, I hoped to get the first badge (155kmi)

At 155kmi, I was hopeful to get to 200kmi

At 200kmi, I was hopeful to get to 250kmi

By 250kmi, I realized that if I do not &$*% it up, it is likely to get to the third badge (~620kmi).

Do not worry about longevity -- drive it and enjoy it as the car will likely outlast you.

Here is a post detailing the research:
http://db.mercedes.cx/sec/200204/03/0009.html

Basically, you replace your drain plug with the intake and send the output through an optional filter to the block. I bet it would work nicely on the older MBs where you can tap the other end into the oil-cooler network. I have yet to make this mod, as I do not want to install it on an engine whose bottem end is already worn. Cheers, Andrew Seidel.

JHZR2,

Regarding your speed, don't worry. These engines are designed such that maximum speed and constant sustained speed are the SAME. :D I believe for your example it's ~100mph. The highway runs are good. Be sure to floor it at EVERY opportunity, especially on long climbs w/ AC running under heavy load. This will serve to keep the engine free of carbon build up and associated heavier smoking than usual. Your "smoking" seems good, so keep up whatever you're doing.

JMH,

Most important thing of all is to never drive it on salt covered roads or get ocean spray on your car. What good is all the maintenance on the mechanical parts if your body rusts apart and you fall thru the floor.

I never take my good 300SD or 300SDL out of my garage in the winter. I use old junkers in the winter and all the rust accumulates on them and there is none on my good MBs.

P E H

I'm going to drive the 190 until the body rots and cannot be driven any longer. When that happens I would like to transplant the engine into something.

7 qrts?!?!?
I put 4 in from an empty engine and it looks like its going to overflow on the dipstick
out of curiosity, I dont have an owenrs manuel but what are the ratios for these cars?
how much tranny fluid does it hold with or with out torque conv. how much oil and how many gallons of fuel
i can never fit more than 12 gallons in but I'm afraid to let any car go below what always appears to be 1/4 mark
call it paranioia but you know how reliable those good old american fuel sensors are "oh I have a 1/2 tank left chug chug gurgle cluck sighhhhh" famous last words of an american car driver:D

thanks,

Jeff

Jeff,

Just exactly are you talking about I.E. ratio for these cars, ETC? What cars, ratio of what to what?

You must be more clear and specific with your questions to get answers.

P E H

oh I just wanted to know how much "juice" these 300 sd's hold

tranny fuel and oil thats all

guess I worded it wrong

my bad :)