The best car in the world - $5,000
 

I have been driving my 1983 300SD for 14 years, owned it for 17 years. Three of those were with my mum.

I remain satisfied that this is not only one of the best cars ever made, it is a superb value on today's used market, if you do your own work. I prefer the W126 S Class to the W123, as you get more luxury for your dollar, though some might argue that all those seat motors etc. are another thing to go wrong. That is not my experience. I also have a strong preference for the aesthetics of the W126 over all the other big Mercedes sedans, but that's just my opinion.

A quick perusal of Autotrader.com for 1983-1985 300 SD cars discloses 37 US listings between $2,500 and $5,000, with mileages of 150,000-300,000, where disclosed. Stated differently, these cars are abundantly available and cheap.

If you can handle a diesel's leisurely acceleration, can live without air bags and ABS, and are willing to catch up on the deferred maintenance that many second and third owner cars suffer from, here are the economics.

You need a pre-purchase inspection - the mechanic checks compression and the transmission, you check all the accoutrements, not least the body (body work is expensive) and the interior (leather is also expensive). My inclination is to try to get a car with no more than 200,000 miles on it, giving you a good chance of another 150,000 before top end work is called for. Focus on one with all service records, with an emphasis on regular fluid changes. $200 for a thorough PPI.

When the 300SD returned to me three months ago, it had only had basic oil changes performed. Diesels are not low maintenance cars if they are to run properly. Their best (and worst) feature is that they will run horribly out of tune, but the goal is to have a car that runs perfectly. Mine, then, was a victim of deferred maintenance. Fluid leaks were abundant, rubber was shot and the transmission shifted horribly. Here's what I had to do to make it perfect, with parts costs estimated:

Start with a maintenance service - filters and fluids $150.

Worn discs dictated a brake job, $70 for the discs and $40 for pads.

A rough idle can be cured by new engine mounts , call it $30, and a good injector overhaul followed by Diesel Purge. That lot adds $15.

The oft neglected sliding roof costs pennies for the grease.

A suspect charging system is frequently fixed with nothing more than a new alternator regulator for all of $25.

Fix that broken window for all of $2 and some labor.

A bad fuel sender replacement is expensive at $80, but essential, as is a new tachometer amplifier at $70, the latter nice to have.

If the timing chain is stretched much over 7 degrees, replace it or risk a top end rebuild. Nice to have this checked at the PPI - the illustrations are for a V8, the I5 is even easier to do. $150 in parts for the chain and tensioner.

The bypass hoses probably leak, and that's an easy fix for $30 or less.

There's a good chance the cruise control is faulty - a $150 fix.

A leaking differential is an easy fix, if messy, costing some $5 in RTV silicone and $7 in gear oil.

While you are at it, do a transmission service as it's probably way overdue, then follow up with a thorough transmission tuning and make it shift like it did when it left Stuttgart 20 years ago. $35 for the filter kit, $15 for the ATF.

Finally, if your shifter goes click-click, replace the shift linkage bushing and things will feel right - $3.

While you are spending wildly, $15 or so will replace those sway bar links.

Now you get to the cosmetic stuff.

Some cracks and discoloration in the seats are fine, fix them with ColorPlus poducts available in the tint to match the originals - $200 if you go crazy and redo the whole interior. Major tears and dog marks are not fine - find another car.

Leaking seals must be replaced immediately, or you will get rot. A tricky job - reckon on $80 for a door, $40 for the trunk, and don't sniff the glue.

Now that you are almost done, and given that you share my insanity, do your baby a favor and add keyless entry, keeping costs down to $125 by learning from my mistakes. That is, of course, a needless luxury, but you owe it to the car and yourself.

Oh! but all those special tools I will need, you say. Well, the bent valve wrenches can be made at home or bought for $60, the crowsfoot injection line and deep 27mm socket add another $100, a vacuum gauge for the tranny work $35, an Eezibleed for the brakes $40. Tools that will outlast the car.

Let's see. That lot adds up to some $1,500 on top of the cost of your car. Then, enjoy the lower vehicle license fees the state will charge you and drive the best car in the world for another 150,000 miles. But most importantly, enjoy your ride in the Best Car in the World. Just remember to keep the maintenance up.

And, if you are really good, take pictures of all of this as you do it so you will remember how to do it next time....

And here....
 

....is the result.

Excellent, excellent Tom, I have greatly benefited from your generousity. I will be folowing your fuel return lines, ATF change and engine mounts guides next. I had recently paid $4200 for a 85 300SD with 117K miles on it with all the service records. I have changed air, 2 fuel, and oil filters and have adjusted the valves and replaced the hood pad. Thanks you.

Nice car!! You have a kick-ass website too. RT

I'm about 1/3 third of the way through your list. I don't know how you work so fast but I can't argue with the results. She's a beauty!

Thomas, you are a very generous guy to share and document all that information for us.

The car looks great. I'm actually not a big fan of the color brown, but it looks great on the 300SD. There are not many cars that can wear brown respectably. Another car that looks good in brown is a 1976 Cadillac Sedan de Ville or Fleetwood Brougham d'Elegance.

this is the car!!!

I have set my mind on 300SD. I am looking at an 84 and an 85 with 240K km on them for I think very resanable price ofr $3900 canadian.

I cant wait to get it to my driveway.

Mslipac - One note of caution on the 1985
 

The CA models (maybe others, maybe Canadian?) used a ceramic trap oxidizer to filter exhaust and meet tightening pollution laws. This wretched device would, with age, shed sand like particles into the turbo, destroying it and resulted in a retro-fit by the factory of an exhaust catalyst replacing the trap. No charge, but you may have to fight them.

Something to check.

Also, while I make light of the labor, take a look at those pictorials - it's a lot of work to make it really good, though it can be awfully good if you are prepared to pace yourself and do it gradually.

What these neat pictorials never show, and what every mechanic knows, is that nothing ever goes by the book. Parts break, bolts bind, you hurt yourself, spares are back ordered, you are fighting a deadline all the time if it's your daily driver, and on and on. Just go in with your eyes open, be patient, get the very best car you can, then fix it. Patiently.

It's worth it. And I'm quite serious - as long term, economical transportation, I do believe this is The Best Car in the World. But then, again, I am a confirmed Luddite.

Why an old 1983 car? Today's WSJ published the J D Power list of new car faults. Predictably, Lexus was way first. Hummer and Land Rover (the latter, equally predictably) were dead last. MB was exactly in the middle of the pack. A mediocre product for consumers with mediocre expectations.

thanks for the tip!
 

ill be sure to check as much as I can

You guys think I should check for turbo shaft play while I am there?

Frank King, the long time technical editor of the Star Magazine, wrote a long two page article on this Trap Oxidizer.

He basically says that it was introduced in 1985 on California versions of models with 617.592 and 617.591 diesel engines, and was also done in 1986 to California cars with 603.961 engines. In 1987, use of trap oxidizers was extended to cars with diesel engines 603.960 and 603.961 in all 50 states.

"The component was a filter known as a trap oxidizer, designed to meet California emission standards. Located between the exhaust manifold and the turbocharger, the trap oxidizer is a monolithic labyrinth of ceramic rods housed in a steel cylinder.

Due to the extreme range of temperatures to which the trap oxidizer was subjected and the vibration inherent in the application, the ceramic monolith did not have the expected service life. Sometimes pieces of the ceramic, ranging in size from dust to chunks, broke off and were blown into the turbocharger. The abrasive ceramic particles could damage the turbo blades. As a result, Mercedes-Benz instituted an extended exchange or warranty policy. Owners of affected cars were protected from repair expense due to trap oxidizer failures.

Mercedes Benz developed a new device called an oxidation catalyst with sufficient durability to replace the trap oxidizer.

Owners who have had the job done report a noticeable performance improvement after installation of the oxidation catalyst, probably due to the decrease in exhaust back pressure."

I hve read that....
 

....in extreme cases, the particles would blow hrough the turbo and go on to destroy the engine too.

Re: I hve read that....
 

How could this possibly happen if, as was posted, the unit was located between the exhaust manifold and turbo? Yes, I can envision material damaging the turbine section of the turbo, but no making it into the intake side.

I would think that anyone with one of these would be searching the junkyards for a "normal" exhaust setup. I know I would be.

WAGONPILOT

wow!
 

thanks for putting that site together - it has just about every little tweak / maintenance item that I'm currently buying parts for!

1984 300SD 180K-ish miles
2001 CLK55 6500 miles

~shell
dallas

productive three day weekend
 

With a lot of print outs off the http://www.pindelski.com/ website, I accomplished quite a bit on the 84 diesel. The car has been in our family since new and was recently passed on to me by my mother (who now drives a minivan - go figure!). Current odo reading - 181K.

*The following is the list of repairs / maintenance completed:

2 cans of diesel purge
fuel pre filter, fuel filter
new oil cap, oil and filter
power steering fluid and filter
new radiator hoses, thermostat and coolant flush
new sway bar links
new exhaust hangers
new rear brake lines and brake fluid
new motor mounts
new air assembly mounts, braket, filter and just a thourough cleaning of the air assembly
transimission service (fluid and filter)
and a lot of brake cleaner used to clean up whatever part of the car I was dealing with at the time

*probably next on the list:

new belts
maybe a water pump for good measure
flex disk for good measure
leaking rear diff

*If I get the courage:

valve clearance, valve cover gasket
timing chain

*parts on the way:

new improved fuel handpump
new improved air filter / valve cover breather tube
**************.com dash light upgrade kit and tools

Is it just my car or do these things just always seem to have a leak?

Now I wish I'd gotten a diesel... sigh