300SDL 1987

Kelley Blue Book for that car (private party) is $4300 in good condition, or $4800 in "perfect" condition (this means there is absolutley nothing significantly wrong with it, no scratches, dings, quarks, anything... it's in new condition). Dealer bluebook is $6475.

I paid $6600 for my 170k 87 300D from a dealership, which was just barely reasonable in my eyes. I ended up getting a new radiator and a transmission rebuild too, so I'm happy.

In my honest opinion, $6,000 is a fair price for an OM603 car -- but I see their immense value. They only came to the USA for one year in two platforms, and they are said to be the best Merc engine/chassis combos ever made (both the '87 300D W124 and '87 300SDL W126). You've got more power than stink but they sip diesel (I've gotten 30mpg at 70mph), wonderful sound that's pretty reasonable on the freeway, nice to work on, fast (129mph on the 300D) and they'll last a lifetime so long as you don't overheat them.

What to watch out for -- the normal diesel things. Check the oil, see if it's got any water in it (and check the coolant for oil), this would mean a warped/cracked head or a bad head gasket due to overheating. Make sure it doesn't use water or much oil (IE very little, if any oil and no coolant should be gone after a 100 mile test drive). Check the upper radiator hose in the morning when the car has not been started -- it should squeeze squishy, if it's hard (like there's pressure) walk away, bad head (or headgasket). Start the car cold, make sure the glow plug system works and the car should idle very nicely after only 2-3 seconds of slightly rough cold idle. Pull the oil cap and see if you get any puffs of smoke (blowby = bad rings). Make sure the transmission shifts nicely but doesn't slip or flare. Floor it and make sure you don't get gobs of smoke (bad rings). The car SHOULD snap off the line like petrol engines, if it doesn't absolutley LEAP don't worry (just need to adjust the ALDA, e-mail me for more instructions). Turbo should come on at around 2100rpm and pull hard until the shift, which should happen at around 4900rpm. Once the car is warm, put your hand behind the exhaust while the car is idling... you should feel no moisture (bad head) and no irregular exhaust pulses.

Here's a scary one -- once the car is warm, put it in neutral and pin the throttle for a few seconds. The tach should climb to 5250rpm (+/- 250rpm) and stay there, that's the fuel pump governor. If it's any lower or higher than merc spec, you might need a new fuel pump... not good.

Check the normal body stuff -- look for signs of major damage (bondo on the fenders), turn the wheel all the way to each side and measure from the fender to the outside of the wheel on both sides, shouldn't differ more than

1/4-1/2 an inch. Make sure the tread on the tires is wearing evenly. Make sure all the electric goodies work, climate control, etc. Check the alarm -- roll down the window, lock the car, then unlock the door with your hand and open it... horn should go ape. Make sure the car tracks straight, if it pulls very slightly to the right that's normal. Brakes should stop the car on a dime (they are EXCELLENT brakes), ABS should make sure there is no lock up and the car should not pull to one side under hard braking. Of course no vibration or abnormal noises, brakes should be linear, no uneven surges (warped rotors). Did I forget anything?

Good luck, hopefully things work out and you can get yourself a OM603 engine. They truly are blissful!

Mike

These fine cars come with one caution: that the engine's cooling system be kept in top condition. The engine has a cast iron block and an aluminum cylinder head; these dissimilar metals expand and contract at different rates and the engine tolerates this so long as it isn't overheated. Overheating will cause the headgasket to break and may also crack the (expensive) aluminum cylinder head.

So, if you proceed, you'll have a fine car, but don't speed up long steep grades on very hot days with the A/C on full blast and the engine's temperature gauge bumping the RED mark for it may be an expensive drive. Be aggressive about the engine's fan clutch and keeping the radiator clean, both inside and outside and have it rebuilt if there's any doubt. With these actions the car should perform well.

$6,000 for a car in perfect condition seems reasonable, if YOU really like the car. Edmunds.com has an older car pricing database that may help you with the price.

Mike:

Thank you very much for your very detailed and knowledgeable message. The owner of the SDL did mention that during a cold start the engine is rough for a minute or so, not the 2-3 seconds you mention. He also said that he sees white exaust smoke for a short while which dissappears once the engine warms up. Are these symptoms of great concern? (I am yet to drive the car).

Best Regards, Raj

transmission

TGL:

Thanks very much for your very helpful message. Does this car have an effective A/C? I live in Gainesville, FL where summers are hot and muggy and an effective AC is a must. Best Regards, Raj

Raj,

The stuff you stated sounds like the car is due for some new glow plugs. If the car runs fine once it's warm, I'd say it's a safe bet the GPs are the only problem -- try to barter him down a few hundred dollars because of this "flaw", or get him to replace the GPs until the car truly is in "perfect" mechanical condition. There's always the chance that something in the system isn't quite right, so check to make sure the glow plug light stays on for 3-6 seconds (IIRC) when starting cold.

By the way, I finally got a big Group 49 battery (really big battery, in the

1000cca range, the right battery for the car) for my car, and the thing doesn't skip a beat on idle even when started cold in 50deg ambient temperatures. Idles very well within literally a second after starting. Even with my old 690cca little battery, idle would be bad for only a few seconds.

You asked about the air conditioning -- I have a 134a converted system, and the cooling isn't really very good. On 95-100 deg ambient days, the car will NOT cool down unless it's moving at 30mph or more. In heavy traffic, it keeps the car tolerable... barely. With recirculation on going 70mph on the freeway, it's cold as ICE. Very odd... apparently non-converted R22 systems fare MUCH better.

If you do decide to get the car, drop me a line at snipped-for-privacy@cox.net -- I've got some OM603 tips and a good friend who knows quite a bit about the engine. There's even an intercooler kit that's out there that can boost power from

148hp-200ft/lbs to a whopping 178hp-250ft/lbs, but it's for euro cars (no EGR) and we're still waiting to see if the company will make a modified kit for US cars. Imagine a 8 second 0-60 car that still gets 30+mpg!

Good luck! Mike

Mike:

Thanks again for your insightful comments. The car is in Washington DC and I might go over there and drive it back to Gainesville. I wish the car was here so I could get it check with the local mercedes mechanic. Perhaps I should take it to a reputable mechanic in WDC and get it checked out before buying it.

Reg. the a/c, doesn't the car have a fan blowing on the condenser, to cool it at slow speeds? I take it at freeway speeds the there is enough flow to cool the condenser effectively. My Saab behaves very much the same way with the coverted 134a system.

I have never owned a diesel. So I am a little weary of them. I hope the car isn't too sluggish . My Saab has terrific throttle response. A friend of mine send me some articles from a book called "Diesel's Engines". Fascinating book on the evolution of diesel engines.

The 300SD and SDL (81-87) are rated rather highly. It mentions that the trap oxidiser in these cars ban be troublesome. I understand MB offered to replace all trap oxidisers at no cost in 1996 with a newly developed "oxidation catalyst". The article suggests to ask for proof that the necessary work has been done, and if not to avoid the car. The article says these trap oxidisers can be a lot of trouble. Do you know anything about this?

The highest rated car in the article is the 1998 E300 turbodiesel with 176 Hp and 244 ft-lb of torque and the worlds most fuel efficient luxury sedan. Does 0-60 in 8.5 secs and gives 34 mpg! Boy, that is the car to have, it seems.

Best Regards, Raj

got

NADA rates the 87 with 172k at: low retail $5350 avg retail $6750 high retail $7900

Low Retail Value A low retail vehicle may have extensively visible wear and tear. The body may have dents and other blemishes. The buyer can expect to invest in bodywork and/or mechanical work. It is likely that the seats and carpets will have visible wear. The vehicle should be able to pass local inspection standards and be in safe running condition. Low retail vehicles usually are not found on dealer lots.

Average Retail Value An average retail vehicle should be clean and without glaring defects. Tires and glass should be in good condition. The paint should match and have a good finish. The interior should have wear in relation to the age of the vehicle. Carpet and seat upholstery should be clean, and all power options should work. The mileage should be within the acceptable range for the model year."

High Retail Value A high retail vehicle should be in flawless condition. All power equipment should be functional. The paint should match and have a high gloss finish. The carpet and seat upholstery should be clean and have minimal wear. The engine should start quickly and run smoothly. The tires should be like new with a spare and jack. The mileage should be significantly below the acceptable mileage range for the model year.

I am somewhat suspect of the NADA values, as there is no milage adjustment. My car, a 1987 300SDL with 132,000 miles, is valued at exactly the same as one with 172,000 miles. Great cars, but certainly there would be a difference in value on like condition vehicles, where the milage spread was

40,000 miles.

Any thoughts?

TGL:

I read in an article that that the trap oxidiser in the 300 SD and SDL's can be troublesome. I understand MB offered to replace all trap oxidisers at no cost in 1996 with a newly developed "oxidation catalyst". The article suggests to ask for proof that the necessary work has been done, and if not to avoid the car. Do you know anything about this?

thanks-Raj

Paul:

I agree that NADA values do not reflect mileage properly.

I read in an article that the trap oxidiser in the 300 SD and SDL's ban be troublesome. These oxidisers are used for emissions control. I understand MB offered to replace all trap oxidisers at no cost in 1996 with a newly developed "oxidation catalyst". The article suggests to ask for proof that the necessary work has been done, and if not to avoid the car. Do you know anything about this?

Best Regards, Raj

adjustment.