of course we all hate the 603, but why do you hate it the most?
 

Is it because of the crap design of the head?
The cracks in it?
The breaking headgaskets?
the clearly dumb designed and malfunctioning cooling system?
The lack of torque for such a huge engine?
The breaking turbo's?
The leaks all over the engine?
The fan that will never come on when it has to?
The way it starts like it is on the verge of dying, even after 20 seconds glow?

or all of the above?

why o why does no 124 603 ever have the cooling fan come on. why??? what is so hard?
god I hate them.
who needs a wagon???

If that's been your experience with the 603, it seems clear you've never owned a good one.

I hate how crowded it is to work on the glowplugs thanks to the charge pipe. I hate removing that crossover section EVERYTIME I want to get into the injector area to perform whatever needs to be performed (compression test, washers, leaks, spray pattern, or whatnot).

That's it I suppose. I've never had any serious problems WITH THE 3.0 liter. The 3.5 however belongs in a dumpster.

ill take it off your hands :D

We don't
 

You don't know the joys of a 6 cylinder diesel when that turbo comes to life.
No torque? Absurd.
Sounds like you have no compression.
Put it all in order and then complain.

this is my 3rd 603. they have all been slow. but maybe that's fast to others, who knows. compression is fine. turbo as well.
the only decent 603 I ever had was a 350sd. that had torque! wow.

If its the one in your sig for $700... got pictures anywhere? I could use a spare wagon ;)

I love mine! 265k miles, and I have the original head and head gasket, turbo, and IP. My cooling system works perfectly and has been totaly trouble free.(because I replaced every last cooling system part 3 years ago, nothing lasts forever!:D) I don't really have any oil leaks, doesn't burn any oil, always starts regardless of temp.

On top of that its pretty smooth, has decent power, and returns 21mpg-23mpg around town. Considering that a 560SEL in similer use would return about 12mpg, its a very good car for its day.

The 603 is a great engine, I have had mine for almost five years now, I'm never going to get rid of it. I have put a lot of work in my car, but most of that was into the car itself. The engine has been damn near trouble free. Actualy other than a few accesory problems when I first got the car, I don't beleive I have ever had an engine problem. Its been the most trouble free part of the whole car!:D

Pretty much all MB diesels are slow.:D

300SD/L, 350SD/L=SLOW W126
560SEC AMG Hammer Wide Body with a 6.0L V8=Fast:D

If I could easily swap my 617 for a 603, I would.

If I could swap my 603 for a 606 I would!:D

I'll agree with the lack of power and torque 100%. There's some hills where I'm at, sort of the foothills of the mountains, not even seriously in the mountains... there's some hills that from a dead stop, I put my foot on the floor and I'm almost afraid it won't even climb it. I thought diesels were supposed to be able to tug anything... but I've seriously thought I was going to end up not making it up a moderate climb before, not even a serious mountain road.

Changed all the fuel filters until I'm blue in the face. Removed EGR, etc. Nothing helps. It's just weak.

Turbo seems about useless. Don't know how you tell if it's "working" or not. You can easily feel a blast of air from the crossover pipe when you rev the engine, but I have no idea if it's enough pressure or not. Turbo leaks oil worse than the rest of the engine.

Trying as hard as I can but I'm starting to wonder if I've even got enough to work with or not.

That's the 98-99 e300 turbodiesel, right? If I had the funds, I wouldn't even worry about a swap. I'd just flat out sell and buy. Same with a 300sd though.. .but I've got so much in this SDL at this point that I literally can't afford to sell it. not yet anyway. If I do anything I'll just keep saving and add to the collection. The 98-99 is out of my price range until pretty much post-college -but if the next two or three summers yielded enough savings to start out with a mid-range 300SD and work with it for a while, I think at this point I'd do it, even if it meant taking the SDL off the insurance for a while.

My 603 is the love of my life ... so don't ask me to commisserate. :D It isn't perfect ... my god, the thing throws a new challenge at me every week it seems. But most of them are small challenges, and because of the car, I've learned (or tried) a lot of things I never would have even been aware of otherwise. Whether you have a 603, a 617, a 606, it's all going to come down to how you deal with the imperfections ... and luck. You may just be unlucky enough to have had a string of lousy cars. A 603 should not be "slow." They aren't going to toast most cars off the line, and they feel heavier than a gasser, but if it's slow, something's wrong.

Different people prefer different cars. I can see why some guys like 617/616s better, but I love the 603. My personal approach is figure out what you like, stick with that, and don't waste time complaining about or bashing the other (well ... there's nothing wrong with some good-spirited ranting now and then :D ). Maybe you've gotten bad 603s, or maybe you're just not a 603 guy ... but, as others have suggested, if you want to pawn off your 603s, many of us would be glad to give them a loving home ... :kiss:

ok I drove it home just now and realized the ac relay isn't hooked up. maybe that's why the front fan won't come on. and thus it overheats.
and yes it is fast enough, you just gotto floor it and keep the rpm's high. that wasn't the case with my 350. that had a turbo that spooled very early in RPM's. double blade. that had torque like a V8.

but still. I will not buy a 603 engine benz ever again. They are junk compared to their older stuff. and any mechanic will tell you the same thing.
squeeky 124, eating tires, needing shocks etc etc.
stick to your 126 gentlemen!

I think this pretty much says it ... a 603 is fast for a 20yo diesel. But folks who think it's going to be really FAST are of course going to be left scratching their heads. 0-60 is nine-point is nothing to be ashamed of, but it's not going to plaster you to the back window. Now a new E350 BLUETEC ... that's fast ... But I still wouldn't trade Bodhi for one!

I admit the 603 has some good features. But... I just don't have a nice fuzzy feeling about mine the way I do the 617. The 603 seems so much harder to work on... crowded engine compartment comparatively... seems to me anyway... even if the 617 is smaller under the hood, more of what you actually need to DO to it can be done without so many scraped knuckles. Everything we have tried to do on the 603 that was a major repair has been a fight due to breaking/broken plastic pieces EVERYWHERE, no hand space, having to remove four things just to get to piece number 5... that darn crossover pipe... stuff like that. It's not that it's a terrible engine it's just... it seems more difficult to work on, more electronic (bad thing), and more finicky. Most of my problems (over 50% anyway) have been electronic, and the 617 has less electronics. The 606 is a lot more electronic, I realize that... but it's ten years younger too, which has to make it a LITTLE bit less problematic.

I'm not criticizing the 603 by design, necessarily. My personal example seems pretty unreliable and working on it is very frustrating because it's hard to get to what I need to get to, and it's so electronified that it's nearly impossible to trace some problems. (like my shutting off in traffic)

If you think your 603 is slow, your going to hate the 617!

If you want a fast car buy a gas MB. MB is good about that, if the diesel is to slow they make a number of 300hp+ V8's and V12's to chose from.;):D

I will say the new CDI's are pretty quick, lots of torque.

The turbo should spool at just over 2,000 rpm if under load. I haven't floored my car anytime within the past few months, and that includes hill climbs and merging onto the interstate from the onramps. Again I'm not saying my car is a dragstrip stud ... I'm just saying something sounds amiss with your experiences.

I've spoken to more than one mechanic who say the 87 300D is a really nice car. My regular mechanic has a fabulous reputation, he has been working on these cars for decades ... and he's never told me the 124 is "junk." He has said the 126 is certainly a better suspension ... much more robust and easier to work on. But he also said the 126 is better than the 123. And he's never said the 123 or 124 are by any means "junk." A 124 is a different style car ... it's a little more sporty and it's not as high-end as the S class. What do you expect? And if you want to talk about mechanics bashing cars ... ummm ... 350 engine ain't the princess in the royal court of MB motors. Personally I don't think that means it isn't worth having, if you like it. Like I said in my previous post ... it comes down to tolerating imperfections and working through the shortfalls, whether it's the prospect of a cracked head or the prospect of a bent rod. Any of these cars, when you buy one, you take a chance at certain flaws biting you in the behind. Find one where the good outweighs the bad, in your mind, and go with that. If that's the 350L for you, get one and enjoy it ... but I don't think there's a need to go quite so berserk on the 603/124.

I don't need top speed at all. I just need a little torque boost. If nothing else, the 617 will feel better to me because the turbo will actually work a little sooner. The best friend I keep quoting her 300SD in every post... I've been following her to places for years with the rest of the crowd. We both put our foot on the floor and she leaves me in the dust.

Attraction of the diesel was the racks-up-the-miles feature that the gassers can be made to display - but only some of them. That's part of why my 300SDL is such a disappointment.

In that case I've got low compression, blown turbo, or some other serious problem. If I didn't hit the floor on every on-ramp - even the downhill ones - I would get killed at the other end. Don't have to drive it that way in-town, but pretty much I live on country roads, and I go 2/3 of the way to full pedal just to get moving from a general old stop sign, no matter where I am. Not a fuel delivery/filter problem, that's about all I know.


I should mention that although it's a dog on most days, for some reason it does have the occasional good day when it feels almost like everybody else says it should. But then, the next day it's back to being almost dangerous. Some days I feel like (although I've never driven one) I could do better with a 240d 5 spd.

Have you worked on the overboost protection circuitry any? What it sounds like is 99% of the time you aren't getting any boost, and then every so often you are.

I couldn't even FIND the overboost stuff for the most part. My searches tend to just confuse me. If somebody knows where to start looking, and can say "put your finger on this hole and see if something reaches out and grabs it" then I can start diagnosing. I don't understand how half of it works. The oil leak concerns me more... it doesn't just pour oil out the turbo but it might as well. It comes out the crossover pipe... it tries to come out at the block off plate... it just drips and drizzles majorly out... I can't remember exactly. Somewhere on the pipes coming out of the turbo headed toward the engine. The piece of pipe that the EGR used to sit sort of over, is covered in oil now. Does this mean the turbo is shot? Seals or something?

How to rebuild?

Something is wrong with your car, because a properly tuned stock 603 is at least two seconds faster to 60 than a properly tuned 617. On a straight up race between a 300SD and an SDL the SDL should pull on the SD.

It sounds like your overboost line is plugged, or just no there. This is not the original engine right? So the whole system has probably been hacked by a third rate mechanic.

Buy the CD if you don't already have it and go through the whole system.

I have to admit the 87 300D I had was a blast to drive. It had lots of power and got good mpg's as well. The only other good things about it was the cruise and A/C worked. Everything else about it was a POS. It wasn't a good example and was pretty much falling apart when I got it. It probably wasn't very well maintained in its late life.
It was a PITA to work on. It sounded terrible when starting it up after it sat a few hours. It ran hot in traffic or going up hills.It's electronics were a nightmare. Maybe if I had a better example to start with I would have a better opinion of it.

Would pay my weight in gold for factory paper service manuals. Have the CDs but the pdfs are so blurry and so generic that I can't do much with it. Haven't found a vacuum diagram that matches my car yet. You are absolutely right about its being mechanic-ed on by someone who knows a lot about Benzes, to judge by his inventory.. but who doesn't even hesitate to cut corners.

Which line is the overboost line? That SD (stock) definitely outruns me. I don't top out as fast as she does but she can beat me to 60 with no trouble. Nice little cloud to enjoy, though, so it's worth it :D

It's not the original engine, when the car had 285,000 on it, the engine was put in that SUPPOSEDLY had 160 or 170 thousand on it, nobody really knows and I should have red-flagged that lack of records when I bought it. Oh well... but anyway, I have no idea the true mileage of the engine, but it's definitely not original and it definitely had some corners cut.

The 603 we had had plenty of torque. Floor the accelerator at low speed and i'd get a good shove to the back of my seat.

Handled better than the W123 too despite the extra weight. A bit more stiffly sprung perhaps.

The overboost stuff is somewhat easy to find, if it's actual there. Look at the ALDA, and look for a tube running over to the drivers side firewall, just in front of the wiper fluid resevoir ... the tube goes into the top of a boxy little thing affixed to the firewall (there's a photo of it in post #13 of the thread here ... http://www.peachparts.com/shopforum/showthread.php?t=174798 ) ... coming out of the bottom of the boxy thing (the overboost protection switch) is another tube that connects to the intake manifold. If none of that is there, that's a good starting place for what your problem is. If it is there, look at the lines ... if they're black, that's blocking your boost from signaling the ALDA to jack up the fuel to meet the increased air induction. If I had my camera I'd take some nice pics for you ... but it's with my dad on vacation, while I house-sit ...

I don't mean to hijack the thread here ... if you want more info, PM me and I'll do what I can (the overboost circuit is one of the few jobs I've done!).

Your oil leak ... wow, I'd say that's a much bigger problem ... and out of my league at this point ...

Actually I'm the original hijacker of this one, sorry :behead:

Will make a new list of problems and post it or PM a few of the 603 folks.

Can't get out to the car for a day or two probably, depends on what's going on around here. Will re-evaluate after I find that stuff.

Out of this hijack for the moment.

One thing to consider about the 603 is that it starts in 2nd gear. I may be wrong, but I believe the SD starts in 1st ... is that right? You can pop the 603 to first via either the kickdown switch OR you can put the shifter to "2" as you leave the line, then to 3, then back to 2, then to 3 and into drive (think that's the right pattern ... I never need to do it, so I'm not positive). Again, though, I almost never need the kickdown switch and I never put it in first manually. You should get decent torque without it.

It goes manually into first if you put the selector in "2" before you start moving. I do this just to GET it moving sometimes. Kickdown is used frequently as well.

Some days it drives almost like a normal car. That's the frustrating thing. But on its worst day at its worst moment, I have to do all these things just to get it to pull the "fairly steep" hill out of the parking lot. Esp. when the engine is not up to temp. It just almost won't even take itself up that hill if it's not happy.

Seems to be maybe getting a little worse. Think it's related to the ever-increasing oil leak through the turbo. Have gone from 1 quart in 5000 miles to at least two. Sometimes the low oil light is coming on after that 2nd quart at about 3 or 4 hundred miles before the next change, so I ignore it. (Check the stick)

Man, I hate removing the intake just to get at the injectors. It wouldn't even be that bad if the bolts were half way accessible. I have to use a wobble fitting, a universal joint, and ball hex socket to get at one or two of them, and often times the bolt heads become stripped and I come very close to crying.


Also, the 124 body is kind of ugly.

Mine was really slow when I bought it, and I remember just living with it and telling myself that all was alright because diesels are notoriously slow and this diesel was just another example. But one day, I cleaned out the pressure line from the intake to the ALDA and I had a different car!

When I tried changing the glow plugs in the 87 I had w/o removing the intake, I managed to break two 1/4" swivels since they were the only ones that would fit. I started with #6. I actually got it out. Threading it back in was even harder. It didn't quite go back like it did and I probably cross threaded it.:eek::mad:
Anyway I took the manifold off after that to avoid any more potential disasters. With the manifold off I finished sinking the GP in #6.
It was a tough last few threads.
With the manifold off the rest weren't too tough to replace.

I don't think anyone has mentioned the injection system or injectors....are those all in good shape? Hows the timing and such....if its off a lot its going to not perform too well. My dad's 617 is a beast like no other, it will absolutely shove you into your seat from a standstill...and has incredible power....feels very much like a 603 SDL I rode in a while ago. Meanwhile....my car is quite a bit more sluggish off the line, smokes quite a bit more....not as much passing power/torque....but I still have my original injectors. They will be re-built within a week, then we'll see how its doing. His car was lethargic, smoked, and started/idled rough on a regular basis. Had the injectors rebuilt with bosio nozzles, it was a new car. Amazing difference. I just did a valve adjustment on it today too....first one in nearly 30k! :eek: I thought it idled smooth and had power before....now its just ridiculous, super quiet, smooth and powerful... We need to do a 0-60 timing of it.

Next week I will have my injectors done and then I will do a valve adjustment....hopefully it improves mine as well.

Anyways....on the topic of the 603...I think they sound nice, and have great power...judging by the ones I've ridden in.

We got 235,000 miles out of our OM603 in our SDL. I didn't even know about the #14 head until after we sold it. We did have other ancilliary problems such as the trap oxidizer plugging up in 2000, exploding and sending everything through the intake tract. And the radiator blew up once. :D

Recently I was able to get a copy of MB's "Introduction into Service" for Model Year 1987 300TD & 300D. A really useful book. The order # is 6510 1052 13. I don't know if this is the same book as the reprint that MB Classic sells as 6510 1052 02... Anyway, I only mention this because on page 89, in the beginning of the tranny section, it says, "Transmission starts in 1st gear when the selector lever is engaged in any of the forward speeds."

So in July of 1986 when this book was published and sent to dealerships around the US the MB engineers were of the impression that the W124 diesels were going to start in 1st. Is there a general consensus that the book was in error? You would think that it would be easy enough to check, but at the same time I am not sure my transmission is at its operational best.

This book, by the way, has excellent vacuum and wiring diagrams. The intent of this book was to provide the dealerships with a service cheatsheet, if you will, in advance of the release of the full service manuals. It focuses on new aspects of the two models compared to previous models. For some items it will say "this is similar to ..." and other items it will highlight the differences from previous years.

i allways thought it was fun working on my 240d when it broke down, a 5cylinder would be even more fun (wich im going to be swapping into my 240d 4speed here soon im looking for a longblock 617) 603 and 606 would be plenty of fun to work with. (no sarcasm)

It seems to me, they ALL start in first gear by default. At least all the ones I've driven. The gasser W124's start in 2nd gear up until model year 1990. Its annoying, but the early W124's had shorter second gears (2.41:1 vs 2.27:1), and a higher (numerical) rear-end (3.07 vs 2.88).