OM603 300SDL
 

Ive been doing some reading about the OM603 with the #14 head, what Ive read is that in 86 and 87 the only head that came on the 300sdl was the #14, so if a car has a different head that means it was changed either by the owner or mb warranty, correct? So, there are a couple sdl's that i am looking into and have not confirmed with the seller that they have a #14, but I am going to assume they do for now. If this head fails is there anyplace to buy a brand new head, if so where? Or is my only option getting a #22 from a 3.5 engine? Also what do you think about this car, price is steep but seems to be in good shape with low miles and he is negotiable.
1986 Mercedes-Benz 300SDL for sale #1801625 | Hemmings Motor News

I noticed something that looked odd, in the picture of the engine the intake pipe was a tan color instead of silvery aluminum like the rest of the intake, is that anything to worry about?

That car is really pretty. The crossover is just dirty, it doesn't mean anything. It may even be the remains of the preservative that was sprayed on at the factory.

I wouldn't get too crazy about the head. Problems with these heads was associated with the original particulate filter, which is not present on this car (see photo). If the head fails, fix it or replace it.

http://www.westnet.com/%7Emfrank/trapoxidizer.jpg

we let Metric engines in Los Angeles, rebuild some Mercedes cars for a collection,

good work, and so is the price,

Crossover Pipe...
 

That just the old cosmoline on the crossover pipe. Nice car. Still pretty steep price, even with low miles.

Comments on the car.

1) Never trust low mileage on an old car unless it is verified, it is so easy to turn the ODO back. The first digit '0' should be moved a bit up if the second digit is '7'. The '0' is too 'centered' IMO.

2) Engine bay look pristine. If they have spent so much time and effort to clean it up then why not the cross pipe.

3) Price is too steep.

I can sell you one of my SDL at 1/3 the price. But they have 'real' verified mileage at 315K and 365K.

The odometer looks legit to me, but I agree that without documentation it could easily be a replacement or altered, unlikely that this era odometer would fail before 80k miles. Steering wheel wear is a little high IMO for these miles, but probably about right if it is mostly in-town miles.

Either way, I agree that the price is way too high, even though it is a nice car they don't have much collector value and those of us who just enjoy driving them aren't willing to pay that, insurance probably wouldn't reimburse, ... just high.

Looked at the advertisement photos and noticed:

• green coolant in the reservoir which I understand is not the best idea.
• Sunroof wind diverter is laying flat...should be tilted upward when the unit is open.

Re: #14 Head....I've been worried about all the reports for 15 years as my SDL has the #14...Well it now has 422,500 or so miles and runs just fine. Just got back from an overnight San Diego / Phoenix round trip running 75-80 mph for hours. 28 mpg. Daily driver that loves the highway.

Best car I've ever had and there have been many old & new. Easy to work on...Just maintain it! (this site helps big time lol)

P.S. My intake crossover is the same color

Fun old SDL Write Up: "Never buy a 300SDL"
 

Never Buy A 300SDL

"Under no circumstance should you ever consider approaching one of these vehicles. You would be a fool to even waste your time looking or test driving/riding one!!!

The combination of engineering excellence, power plant capability, and the epitome of timeless styling will forever ruin you for the rest of your motoring life! You will spend an eternity searching to achieve that state of motive bliss that only this car can attain. The rush of endorphins that accompany such an experience has yet to be equaled buy modern pharmacopoeia! A fatal flaw is the feeling of fainting/vertigo that will often times overwhelm you on those days when your vision captures the exquisite silhouette as you approach these vehicles in a parking lot! You are much more likely to be struck by a Ford or Honda in this state of euphoria than at any other time, (unless you are blind, deaf, and dumb traversing a mall parking lot on December 23).

Do not! I repeat. Do not! Get behind the wheel of an SDL on an interstate highway and drive above 75, 80, or even 130 MPH! Unless you possess superhuman self control, the family and friends you've will have left behind will wind up posting your missing / wanted poster on milk cartons and diesel pumps across the nation for years to come!

Seriously though, if you like Mercedes Benz and you like diesel you’re going to love this / lust for, these vehicles. Every moment behind the wheel is indescribably delicious. The real deal - 86/87 300SDL 3.0 L six cylinder turbocharged diesel! 25+MPG at 75+ MPH all day and all night, 500+ miles between 20 gal fill-ups.
Yeah Baby… Highway Supernova! One of the finest automobiles ever made!

Good Luck!"

... until you buy a W140. Heavy? Yea, underpowered? Certainly, ... but the high-water mark for M-B Engineering in the 20th century.

OTOH, the 126 is so much sexier to look at.

Do not fear the 14 head.

IIRC some '86s didn't come with a trap. If the exhaust flange behind the transmission has a 3-bolt flange, it probably never had a trap.

The #22 head is the 'official' replacement head for the 603.96 (3.0) and 603.97 (3.5) turbo engines. AFAIK, the #22 head wasn't OE on any US passenger car engine. All the 3.5s with original head that I've seen have #17 heads. A new #22 head with valve seats and guides was about $2500 last year. I don't know if/how the price changed this for this year.

Sixto
83 300SD

If you replace a #14 with a later head, you will need new injectors, injector hard-lines, and new glow-plugs IIRC. A longer bolt in the chain cavity too, head gasket set, probably a good time for a timing chain, guides, and tensioner also. Does that head come with pre-chambers installed Sixto?

Left off updated timing cover. :) Only hard part remaining for me to purchase to do the top end on my SDL.

Those timing covers come on the same engine that has your later head (fully loaded), ...

I know where there's a '91 SD West of Cleveland.

No prechambers included when you buy a new head from MB. Check the archives how to trim vertical prechambers to fit a later head. If you go inclined, that's prechambers *and* lockrings.

Sixto
83 300SD