Compare 123 vs. 124 Diesels - PeachParts Mercedes-Benz Forum

jjalex · #1 05-15-2003, 11:06 PM

I am interested in a comparison of the 123 and 124 diesels. I understand that the 124s are more of a pain if you have to work under the dash, but what about the rest of the car, under the hood work, reliability etc.

I am new to diesel mechanics, and most auto mechanics in general, but I think its great stuff. I just did my first valve adjustment this past weekend and now she purrs like mountain lion on the road.

Is the routine maintenance on a 124 much different from the 123s?

I would like a better ride and maybe better economy for my daily driver, and am thinking about a 90-93 300D 2.5T, but what do you folks think?

Thanks

sixto · #2 05-16-2003, 02:48 AM

Newbie or not, there should be a penalty for asking such questions. Brings out the animal in some of us

Short answer -- it's a matter of taste. Try some of each and decide for yourself.

Sixto
91 300SE
87 300SDL
83 300SD ... any takers at $1100?

Dana B. · #3 05-16-2003, 02:50 AM

Check this recent thread, towards the bottom:
http://www.peachparts.com./shopforum/showthread.php3?threadid=64685

jfikentscher · #4 05-16-2003, 09:13 AM

I have a 1987 300D Turbo. As far as any diesels that I have driven this is by far the fastest!

I have had some minor problems such as glow plugs, blower motor, and sunroof. I bought the car with 136,000 miles on it and now have about 204,000 after about two years.

I would recomend this car highly.

Joe.

slowmoe · #5 05-16-2003, 02:42 PM

I have owned my 92 for about 60K now and have been very pleased. Having owned both the 123 and 124, there is no constest in my mind. But, it depends on you taste.

I think you get more out of the newer cars: antilock brakes, airbags, more comfortable seats, better ride, and 30+ mpg on the 2.5 turbo etc. What has struck me the most about the 124 is that I have had to do so few repairs on it as compared the the 123. The car is just newer and less things go wrong - my experience anyway.

In a large part it depends on what you are looking for, how much you want to spend, how many miles you are willing to have on the car...

The only repair I have not been able to do on the 124 were the balljoints

BTW the only thing I have had to do under my dash is replace a light bulb.

#6 05-16-2003, 02:48 PM

"Mature technology," no embedded electronics, final MB's built to last forever...also think the styling will wear better over time.

lrg · #7 05-17-2003, 02:15 AM

Want anvil like reliability and easy to work on...take the 123.
More refined and powerful but also more complex and, while not hard to work on not as simple either, take the 124.

For me I'll take the 123 for around town safety and reliability. For high speed cruising and comfort, I'll take the 124. The 123 vs 124 debate is the embodiment of the expression, "there is no such thing as a free lunch."

rickjordan · #8 05-17-2003, 09:37 PM

I now own both a W123 and W124 300TD. I am still getting familar with the '87 TD, but so far, Damn!. When that car's turbo kicks in, you can feel yourself being pushed into the seat a bit. The car drives more like a gasser than a diesel. The steering is so much tighter as is the whole body. Despite the fact that the 124 is 50 lbs. lighter than the 123, it feels much heavier. The engine compartment definetly has more electronics to it. The one thing, at this point, that I have found to be a poor design from a maintenance standpoint, is the main fuel filter. There is no room to remove the main fuel filter. I have been told that you have to remove the filter and the mount together, then spin off the filter. With 3 fuel lines going to the filter housing, even that seems cumbersome. I like the set up on the 617 engine better. The oil filter on the 603 engine is even closer to the firewall than on the 617 eng. What I can't figure out is what is the center bolt is for, in the filter cover. All it does is screw into the center stem. Changing glowplugs looks to be a real pain since they are located under the plenum (sp). MB placed aerodynamic plastic shields under the engine and tranny. So any oil changes will requiring removing these.

Ken300D · #9 05-18-2003, 12:01 AM

Rick:

The story I got from the manual on the 1987 300D oil filter change is that the center bolt is designed to come off and release the center post. The cover and center post together are too long to clear the firewall.

However, the center bolt on my filter cover was stuck tight. Rather than take it apart, I found out that the top of the firewall (actually, its a plastic divider) is easily disassembled. You pull off the two long rubber gaskets that fit against the hood, and then the top firewall piece is held on with four clips. Remove the clips, pick up the firewall top piece, and the oil filter housing top clears.

Ken300D

rickjordan · #10 05-18-2003, 12:32 PM

That's exactly what I ended up doing. Now that you explain the reason for the center bolt, that makes sense. I'll try that next time.

#11 05-18-2003, 02:18 PM

Looking at the classified ads, I've found more "new engine, rebuilt engine, etc." on relatively low mileage 124 and 126 diesels with the aluminum heads. The W123's are all iron, which is a stronger combination, that lends to a longer lived engine. I also like the simplicity of the older cars. It makes a klutz like me able to work on 'em. I also like the classic lines of the older cars.

Ultimately, the overall reliability of either model depends on the care given to them. Inspect carefully.

jjalex · #12 05-19-2003, 09:41 AM

This forum is a fantastic resource. You folks are great!

I think I will finish the remaining minor bodywork on my '84 123 to save for my daughter and look for a 124 for myself. The comments about highway driving rang true to me since 85% of my driving is on the interstate.

I realize there are probably a bunch of threads on what to look for when buying a used diesel in general, but is there anything specific when looking at the 300D 2.5T 1990-'93 124's?

Thanks again.