Don't flog me hard-core sdl guys....I'm just seeking some knowledge from anyone that has been there and done that.
After all the money and time spent on my wife's 86 300sdl, only to have continuing problems with exhaust in the cooling system, I am considering ALL my options. This car is WAY too nice to part out although that will be a last resort...tons of new parts, like new tires, near perfect interior. Tearing the engine down again is NOT an option - I have spent way too many hours and found and read too much about constant issues and just don't have it in me to go through this again.
What I was wondering, and again, this is just a trying to consider all my options question: Has anyone ever replaced the engine in this car with a gasoline engine? Maybe a 4.3L? I know the resell value will be gone, but it is already at this point. But would it be possible to do and come out with a really dependable ride that is the master of comfort?
Any input? Thanks!

Most people go the other way.

I understand the not wanting to tear down the engine again. I'm betting that somewhere out there is a rusty hulk of a SDL that's not worth fixing that still has a fine, low mileage, good running engine somewhere in the rust belt just itching for a new home in a pristine chassis.

If you're going to all the trouble to do a swap, why not eliminate all the hook up problems that exist with going to a gasser from a diesel?

Just a thought, since you're considering all your options...

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

[QUOTE=mach4;3141127]Most people go the other way.

Yea, I have discovered that in my search for knowledge and experience on the issue...I own a Dodge Diesel truck...have for years....sold on it! BUT....for every account of how reliable this engine is, there seems to be at least a hundred expressing spending all your free time and life savings keeping the thing going. I have never bought new vehicles so figuring purchase price and interest VS. parts, time and repair cost is not an effective arguement for me. I am a family man, construction worker and livestock owner who loves classic cars but they are not my life. My wife needed a dependable daily driver and after being sold that this was the car, I made the purchase. We enjoyed it for two whole weeks before the gasket blew. Love the way the car drives and handles but don't have the resources or time to keep this diesel engine going....can't afford to sink more money into like engine and still face potentially the same problems. Just hoping to salvage SOMETHING because right now this whole experience has left a bad taste in my mouth and set me back several grand. As much as a love my diesel, we have owned some really dependable gas engines that were VERY dependable, MUCH easier to work on, and just required general maintenance....don't know exactly what all would be involved in a swap, but right now ANYTHING but a 603 turbo sounds like more of a long term possiblity. Thanks for taking time to offer your opinion...much appreciated!

The general rule is that the time lost in details and aggravation on a motor crossover transplant is going to exceed the time and money needed to find a good used motor. Also the car will be worth less afterwards as it's a frankencar.

Try putting a WTB (want to buy) ad in our mercedes used parts for sale and wanted section. Someone may have a motor. Or want to take on your car.

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Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

W126 diesel cars originally came with OM617 engines. If you can't stand the OM603, I'd put a OM617 in it before I'd try to convert it to a gasser. I would think it would be a far easier swap.

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-Louis

'87 300D Anthracite

That's an excellent point. There are lots of 126 S-Class cars out there with the 617 engine that should be pretty much a bolt in affair.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

Yep, I'd put a 617 in there, would be quite easy. Putting in a V8 or I6 gasser would be a near-impossible nightmare unless you had a full donor car....even then, nightmare. Computers, wiring....

Keeping an originally-gasser one going is hard enough as it is!

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Thanks guys for your input - In your opinion, what is the honest comparison between the 617 engine and the 603 engine as far as beyond maintenance issues/failures?
Thanks!

You'll find lots of opinion, but let me see if I can summarize what I believe to be the case.

First, let me state that my only first-hand experience is with the 617 engine so statements about the 603 and 606 engines are based on perusing the forums and generalizing from group experience.

The 617 is generally considered to be pretty much "bulletproof". It's major problems are the timing chain which can let loose and take out the entire engine, a vacuum pump failure that can take out the entire engine, it's inability to survive a catastrophic oil loss (e.g. cooling line failure) for more than a few seconds, and its extreme cost to rebuild with an associated lack of parts, like pistons. The 617 is a completely mechanical engine so the lack of computers is generally seen as a positive. When a 617 engine fails a different engine is almost always sourced and installed. (I keep a spare engine around for just such an eventuality - cost: $400)

The 603 engine is a more refined engine, providing smoother power and a quieter ride. The 603 3.5 liter, known as the "rod bender" engine is to be avoided unless the engine has been replaced by MB or rebuilt with the new connecting rods and other components. The 3.0 engine was beset with head issues that produced a number of versions with improvements that helped to prevent the issue. Even with the "14" head, if the engine is carefully monitored and never overheated, it can give very long service, but this is a weak point. The engine also has an even bigger vacuum pump issue than the 617. This engine saw the introduction of some electronics, mainly idle control that can be problematic. A huge problem for 603 and 606 engines are the glow plugs that can get stuck and require major head work to get out. Careful maintenance is required.

The 606 engine is even more refined and considered a very desirable engine, however it is almost never swapped into another vehicle because of a complex electronic setup that controls not only the IP but also the transmission. To successfully swap the engine you would need the engine, IP, key, switch unit, ECU and transmission all from the same vehicle. Most people that swap this engine, replace the IP with one from a 603 to get around the ECU issues.

The 617s are very prevalent while the 603 and 606 are considerably more scarce, at least in the US.

Hope this helps.

Others will chime in if I've inadvertently misstated something.

__________________
Current Stable

• 380SL (diesel)
• Corvette C5
• Manx
• Baja Bug
• F350 Powerstroke
• Auburn Boattail Speedster replica

It will be way harder to swap a diesel engine to a gas one.. Way too much stuff to convert. Unless you really know about electronic wiring & all those other complicated stuff.
Why not get a gas car & swap the interior instead. It will be an easier job.
I will be doing a gas to diesel swap soon on a 560. Most of the time thats what people do gas to diesels. 617 would be an easier swap.. :-)

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'76 300D
'82 230CE
'84 300DT
'91 300D 2.5
'86 300D 5 speed
'86 250D 5 speed
'90 300E 24v
'88 560SEC
300TE euro 5 speed
91 350SD
http://i75.photobucket.com/albums/i3...d6605222-1.jpg

(More advice from someone who hasn't done it!) The easiest will be to replace with the same type; then engines that have been factory fitted in the same / similar chassis - the OM617 falls into this category but it is the little things that will bite you in the arse...

...an alternative that hasn't been mentioned in this thread at least is to replace the engine and transmission with something that is locally available and considered to be reliable => in your case that might be an American V6 or V8?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

x2

But if you do go gas a Ford DOHC 4.6L V8 would be an excellent choice. If speed isn't your thing a mildly cammed 2.3L lima would move it around, but only at 140hp or so.

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

what's wrong with the SDL now?

it likely has good resale value even with engine problems.

Gasoline SEL's are prevalent and cheap...
I'm just sayn...

the 617 is noisy, less powerful, and less smooth an operating motor. also, it requires 15K valve adjustments.

the 603 is a better engine in every way. yes, it can be expensive to repair when catastrophic damage is done, but avoiding damage is simple. just keep the oil changed regularly, and with the proper type, and flush the cooling system every 2 years, and maintain the belt system.

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Yes, I have done this conversion in 2004.
It is not a simple engine R&R...

Buying the rusted out donor car + labor $8,800.00 ..
90% of the vehicle wire harness must be replaced + you need all of the modules, brackets, heat shields, exhaust system, etc.
Special Note: The diesel fuel tank and level sensor must be removed, to be cleaned / or replaced.

Would I do it again, yes, today $22,000.00.

The owner kept it four years, as a summer toy.
Lost, due to an unrelated garage AC electrical fire.

.

__________________
ASE Master Mechanic
asemastermechanic@juno.com

Prototype R&D/testing:
Thermal & Aerodynamic System Engineering (TASE) Senior vehicle instrumentation technician.
Noise Vibration and Harshness (NVH).
Dynamometer.
Heat exchanger durability.
HV-A/C Climate Control.
Vehicle build.
Fleet Durability
Technical Quality Auditor.
Automotive Technical Writer

1985 300SD
1983 300D
1984 190D
2003 Volvo V70
2002 Honda Civic

https://www.boldegoist.com/

I wish I knew exactly without having to tear it all down...
Here is the scoop on the car: I bought it in October from a guy who has owned Benz and MANY of them since he was 16; he was in his 40s.
He was VERY knowledge and was sold on this car and bragged and bragged about it's durability and knew every detail about the car.

It had 168,000 miles on it.
He did meticulous maintenance on the car and had any 'bigger jobs' done by a mechanic he had used for years.

Knowing NOTHING about Benz, I listened and studied, and asked questions and read reviews and researched parts and costs...the whole nine yards.
Finally, assured that this was going to be the best car I would ever own, I purchased the car...What I dream to drive!!!Just loved it! Even told my wife that if she tired of it, I would keep it and get her something else. The car ran like a top!

After two weeks of ownership, we drove into the drive after a 30 mile trip and white smoke started billowing out of the tailpipe.
I knew what that meant.
My father in law is a 50+ year diesel mechanic (farm and big equipment), and encouraged me to tear it down.
We both marveled at the exceptional condition of the interior of the engine....clean as a pin.
The head gasket was blown and there was a small crack on the head.
I had it resurfaced to specs, and pressure tested.
Everything looked good...there was a surface crack, like the size of a hair, on the surface of the head between cylinder 2 and 3 that did not involve the water jacket...
I was told that shouldn't be an issue and didn't see how it could be either.
I purchased all new required parts, got a manual and put everything back together exactly according to specs.
I felt like I had conquered Mt. Everest!

I might mention that when I bought the car the owner had replaced the radiator, thermostat and fan belt a couple of weeks prior..he said it was maintenance and he DID replace things on a regular basis, not because they were worn, but because there were X number of miles on them..you can obviously see this was done.

In the meantime, my wife and I set out to fix every little thing that was not working perfectly - switches, headlight covers, mats, a new condenser (because a long ago encounter with a deer and bent the fins pretty bad.)...even purchased a compatible Crutchfield radio/CD player...we had big plans for a great ride.

After the rebuild, I started her up and she ran perfect.
Took her down the road and the temp hand moved pretty fast.
So I came back and re-burped her twice to get all the air out.....temp better but still goes to 100. Never overheated though.
A mile from home the white smoke appears out the tailpipe again.
Don't guess I have ever been so discouraged in my life....I took soooo many pains and went right by the book.

Don't know why car is running too hot.
I parked her for 4 months and pulled her back out Sat.
Man, what a beautiful car!
I just cannot part it out...there are already too many old classics victim to junkyard demise and this is not a junkyard car!

I just don't know where to start and don't have the resources to go through round two and again end up in the same place.

I WANT to fix the car and drive it for life...but I am no expert and there is no one (that I have found) in rural West TN that I trust enough to not send me on another dead end wild goose chase that cost several K and leave me no better off.

Why is it that I continue to read praises on this 603 engine and it seems to me a dead end money pit.
Man, I had to buy my wife a 99 Ford Escort for 1200.00 because all my money is in this Benz.
That old cracker box has 169,000 miles on it, runs like a dream, and is as dependable as it gets....what is wrong with this picture???

If you have any step by step suggestions or opinions, I am feeling encouraged with the help, interest and comments ..just need to know where to start.

.