Hi.
I'm very new to diesel. Thinking to buy one soon.
Questions:
Will it be a problem to start diesel in Chicago winter?
Is 5 cylinder better or 6?
What is difference between 300 D and 300 SD (1985)?
Sorry for easy questions?
Thank you for your time.

Sekal.
Volvo 960

Welcome to the crazy club.

To answer your questions:

-No. Though on the really cold nights you'd have to plug it in so that the engine block heater can keep it warm to allow easier starting in the morning.

-No correct answer to that one. Each of the two models has its own advantages and disadvantages. My guess is that you're referring to the diesels of the '80s, in which case the five cylinder engine is generally considered to be as durable and bullet-proof as they get, indestructible in many ways but also not very refined as its design dates back to 1936. The six cylinder engine has an aluminum head that is prone to cracking if overheated - something you can get away with on the five cylinder engine, not regularly though - but then is more powerful, more quiet, has cleaner exhaust and overall, is more refined that the five cylinder engine it replaced.

- 300D = midsize Mercedes-Benz sedan based on what is called the W123 chassis. 300SD = full size, flagship Mercedes-Benz diesel sedan, based on what is called the W126 chassis. Both cars for the 1985 model year had the same engine.

Hope this helps,

Richard

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver

It helps.
Thank you.
Sekal.

A good diesel should start without the block heater down to 0. The newer ones do much better, 606's seem to be able to go much lower. One member did -25 this winter!

But if the compression is good they will start to 0, below that and you need a block heater.

__________________
1999 SL500
1969 280SE
2023 Ram 1500
2007 Tiara 3200

And now from the 124 model group, 1986 through 1995, 300 D / 300 E / E 300 D and E 320 sedan models and wagon group 300 TD / 300 TE An ever more refined group of Mercedes Benz automobiles, I did own a 123 model 300 DT once

Many diesel diehards here, many love their older 123 models as much as I do my 124 model, but secretly, the 123 guys and gals here would die to have a 124!

As much as I do like and apprieciate the older 5 cylinder, 617's they are called, I prefer the 6 cylinder 603 engine more simply because I know this engine better than the 617. and gets better fuel economy, more power, smoother and quiet too! Both are bullet proof, and if maintained and operated properly, both can achieve 400K and some have gone more miles.

A small percentage of the 603's (1986-87 300SDL) (1987 300D) originally equipped aluminum heads did suffer cracked heads cheifly as a result from trap oxidizers and subjection to an overheat situation generally brought on by poor maintenance. Later the trap oxidizers were removed by MB and new and improved aluminum heads were offered that would eliminate head crack issues. However, most original heads installed in these cars have never suffered the cracks and likely never will unless overheated due again to poor maitenance such as old radiator hoses, bad thermostats, poor flowing radiator due generally to age.

You should check the many threads here in the search section on both these engine types and weigh your opinion. Both are very good, probably the best automobile diesel engines ever built. BB

If you are comparing the 6 cylinder diesel engine to the 5 cylinder engine, that is a difficult decision. On one hand you have more power with the 6, but you also encounter more problems. As far as a w126 300sd vs. a w126 300sdl, the 300sd with the 5 cylinder engine and the 300sdl with the 6 cylinder, I would have to go with the 5 cylinder engine. Even though it is obviously less powerful, it has been my experience that the 5 cylinders are much cheaper to maintain as far as the cost of parts, and much more reliable. But like I said the 6 cylinder is much more powerful, so it is a difficult choice. Having a 300sdl and a 300sd I would say go for a w124 e-class utilizing the 6 cylinder engine.


Knight Rider521
______________________
1985 300sd 315 xxx
1986 300sdl 285 xx

I'll carry the flag for the 95 E300D (W124) These cars have the OM606 engine. 24 valve non-turbo 6 cylinder. These sell for $8K and up.

For me all W124 cars are too small. Even the later E-Class diesels are barely adequate in interior space for me. The W140 diesels, while being very large and very refined, have their own well known issues and the chassis itself is the ultimate in complexity and high maintenance costs. As a result, the only diesels I'd ever consider owning would be the W126s. Among them, the stories I've heard from the 300SDL and 350SD/SDL will keep me away from them for a while. I know, I know, the 603 engine is very good and the head only cracks when so, so and so happens. But that head cracking stuff is rarely ever mentioned in line with the 617, so I'll play it safe for now and stick to it. But still, I'd like to get the new E-Class diesel in 2006 just as my hot rod. 221 HP and 376 ft-lbs of torque and still getting 30mpg/city and 39mpg/hwy : tough to beat. Dump that sucka once the warranty expires.

__________________
1999 Mercedes-Benz S600, 103K miles - garage queen
1988 Mercedes-Benz 560SEL, 89K miles - daily driver
2007 Hyundai Sonata Limited, 31K - daily driver