Looking for my first w123 diesel coupe (C123) - PeachParts Mercedes-Benz Forum

RobertinWC · #1 04-08-2022, 04:41 PM

Hi all, I owned a w124 cabriolet years ago, and have a 1983 911sc for the last 25 years. I’ve always been intrigued and drawn to the classic lines of the w123, and in particular the coupe. I’ve decided it’s time to actually own one and have it essentially as my daily driver. Although I’m semi retired now, and won’t be putting a lot of mile on it, I am somewhat in awe of the mechanicals of these cars.

So I’m looking for one of the turbo diesel models, and based on what I’ve read here I’m thinking 1983 and later? I’m in Northern California and expect to find a rust free car. Any particular recommendations that you might have? Of course if you have a car you’re thinking about selling or know of one I’d appreciate hearing about it.
Thanks for any insights and/ or leads.
Robert

JHZR2 · #2 04-08-2022, 09:39 PM

They are nice cars with a few nuances that you need to look for.

The seals will likely need replacement and real ones are $$$. You want all the seas redone for wind noise. Sometimes getting the windows adjusted is a pain too.

The rear coupe windows often get bent regulators. Taking the rear trim panels off is a pain and has a likelihood of damage. The windows need to be well greased and often helped up and down.

I don’t recall manufacturing numbers or if they made a 1985 coupe, but if so that would be the one to avoid, because it has the Klima relay and different tachometer/computer. If it was a nice 85 vs other junk for sure I’d not be phased by the 85, but given choices I’d look for an 82-84.

They are comfortable cars, the doors are long and heavy and can sag a bit.

Like most of the MB diesel world, people lie about longevity, MPGs, etc. and often are offering overpriced junk. Being in CA you’re more likely to find a clean one though. I had to buy one in LA and drive it home across country to get an ice clean example…

Good luck!

ykobayashi · #3 04-08-2022, 11:49 PM

Quote:

Originally Posted by JHZR2

I don’t recall manufacturing numbers or if they made a 1985 coupe, but if so that would be the one to avoid, because it has the Klima relay and different tachometer/computer. If it was a nice 85 vs other junk for sure I’d not be phased by the 85, but given choices I’d look for an 82-84.

Good luck!

I picked parts off an 85 300CD turbo a couple of years ago at LKQ. It had exactly the same CA spec intake as my 300D and Klima relay and three pin tach/EGR computer. I wouldn’t be afraid of those. They were broken on my car and all the easy fixes are documented here. I resoldered my Klima relay and my AC compressor magically came to life. I also found a bad 10A fuse on my ovp relay and my 3 pin tach came to life. EGR was ripped out and blocked off using Rollguys kit. It’s easy to make an 85 look like an 82 with the exception of the 2.88 diff and CA intake. Shouldn’t be a show stopper.

What shocked me on the CD I stripped was the little differences between the four door. Many of the parts are CD specific. I have always wanted a coupe but chasing down parts for the rarer model tempers my mood. The CD had a much lower production and it was an expensive model. Parts are getting bad enough on the four doors to boot. Something like those rear window regulators would send me packing.

Maybe some of the CD owners can share their experiences.

They are beautiful cars and the ones I come across on Craigslist are tempting.

JHZR2 · #4 04-09-2022, 08:15 AM

Quote:

Originally Posted by ykobayashi

I picked parts off an 85 300CD turbo a couple of years ago at LKQ. It had exactly the same CA spec intake as my 300D and Klima relay and three pin tach/EGR computer. I wouldn’t be afraid of those. They were broken on my car and all the easy fixes are documented here. I resoldered my Klima relay and my AC compressor magically came to life. I also found a bad 10A fuse on my ovp relay and my 3 pin tach came to life. EGR was ripped out and blocked off using Rollguys kit. It’s easy to make an 85 look like an 82 with the exception of the 2.88 diff and CA intake. Shouldn’t be a show stopper.

What shocked me on the CD I stripped was the little differences between the four door. Many of the parts are CD specific. I have always wanted a coupe but chasing down parts for the rarer model tempers my mood. The CD had a much lower production and it was an expensive model. Parts are getting bad enough on the four doors to boot. Something like those rear window regulators would send me packing.

Maybe some of the CD owners can share their experiences.

They are beautiful cars and the ones I come across on Craigslist are tempting.

Yes, as noted I wouldn’t be afraid of it at all if an 85 was found and nice. It’s just another set of tings to look at if/when things fail.

I am a cd owner, so am pretty familiar with the differences. The rear regulators are imo the biggest deal if one actually cared about their operation. It’s near to have the quarter windows down, but not everyone cares.

OP will need to determine how perfect an example they are looking for.

There is a lot of overrated junk out there that is misrepresented too…

vwnate1 · #5 04-10-2022, 11:37 PM

I have a tatty 1984 300CD for sale, ping me off line .

I'd think it'll easily drive to Nor Cal., the manifold to head gasket has a leak so I smell exhaust fumes now .

AC inop, front end rebuilt with M-B factory parts, tranny rebuilt less than 40,000 miles ago .

Not over priced but has -one- rust hole at the lower right corner of the backlight , dings and scratches all over the original paint .

Cracks in dash, tired seats but still comfy .

Maybe I'll drive it to Geo's M-B meet & Greet in La Canada this coming Saturday .

Euro bumpers and headlights,

65 ampere alternator, brand new 900CCA battery, on and on .

NOT a show and shine car but very reliable over the decade or two I've owned it .

I had the engine rebuilt some years back, turbo oo but there's some blue exhaust smoke, might be engine, might be turbo, I don't know nor care anymore .

I had the injection pump and injectors redone by that place in San Fransisco everyone raves about, that alone was $2,000 .

Come look Saturday and tell everyone else how bad or good you think it is, at that place I won't mind tire - kicking .

Clear California title in my na,e with original license tags .

Custom metal European front license tag with the correct Ca. numbers and symbols .

About 500,000 miles .

Maybe someone can take and post images, I'm not allowed to do that here .

t walgamuth · #6 04-12-2022, 08:17 AM

Just use the windows sparingly. The front is too big the rear too small. Figure out where to lubricate them and don't use them any more than necessary.

indybenz · #7 04-13-2022, 06:12 AM

I'll throw in, from my own experience of NON California cars, that even if everything looks pristine, you may find the front and rear window seals (and where they attach to the body) are perished even if you can't see it.

It's really hard to know 100% for sure whether they leak or not, but as you probably know look for the telltale signs of water ingress in the trunk, battery tray, etc.

Just go for it. The W123 is just a fantastic car...even the rusted out ones.

My $.02.

JHZR2 · #8 04-13-2022, 08:08 AM

Quote:

Originally Posted by indybenz

I'll throw in, from my own experience of NON California cars, that even if everything looks pristine, you may find the front and rear window seals (and where they attach to the body) are perished even if you can't see it.

It's really hard to know 100% for sure whether they leak or not, but as you probably know look for the telltale signs of water ingress in the trunk, battery tray, etc.

Just go for it. The W123 is just a fantastic car...even the rusted out ones.

My $.02.

California cars may be worse off because of poor air quality in many areas. Those chemicals can damage rubber.

But in general, these cars are old at this point. Rubber naturally degrades. It’s good practice to pull the glass and replace the seals anyway if the car is going to see a lot of rain or live outside.

my83300cd · #9 04-14-2022, 10:14 PM

I'd go for an '85, last year made.
CD roof line is lower, so windshield and rear glass is something to consider. Rear windows working is a pita to deal with. I kept the replacement lifts when the 83 went away, as I'd like to have another one day.
Lots of parts specific to CD, like the passenger side mirror, vacuum seat locks, interior trim,
Had the front end rebuilt at 255k miles, and it was like driving a new car, tight, responsive and clean thru the curves. Put an '85 rear axel/diff in from a parts car.
Just thinking about it makes me want to sell the fleet to get another one.

carock · #10 04-15-2022, 03:28 AM

I bought an 85 300 CD California car three years ago with 245k on the clock. I bought the car because it was a single owner car, always garaged, and never hit, all in for $5500. The car's top speed was 75 mph and the steering had four inches of play. The windshield was sand blasted so bad it was difficult to drive at night.
I fixed the car up replacing everything in the suspension and steering. I paid to have most of that done as I did not want to mess with it after a nasty accident with a spring compressor on a Lotus Esprit years ago. Every bit of rubber in the engine compartment was replaced. The exterior seals were in decent shape and I am successfully preserving them with regular applications of Aero Protectant 303.
The biggest bummer has been the need to replace the engine. I did quite a bit of work to the original engine like replacing the front crank seal, the valve seals, and the injectors. It ran great for a few thousand miles. The engine developed a terminal head gasket leak due to corrosion on the block's deck surface. Had to pull the engine out and get it rebuilt by Metric Motors. This sort of head gasket failure is common on these cars at this age. Same is true for the V-8 gasoline cars. Every gasket is shot. Fortunately for me the tranny was rebuilt 12 years ago and it has given me no problems.
I have had terrible trouble with the new engine running hot. I tried every known coolant bleeding technique known to mankind on the internet. After two weeks and 9 separate experiments I finally got the temperature to behave by using a vacuum coolant filler and a drilled thermostat. I was just about ready to drive the car off a pier with that fiasco.

When looking for a 300CD I would purchase one based entirely on cosmetics. The mechanical bits can be bought, but all the cosmetic bits are NLA. Most of the mechanicals are in poor shape on these cars. You can rebuild them bit by bit and sort of perform a 'driving restoration" while you fiddle with it. It is important to rebuild the entire suspension and much cheaper if you do everything in the front or rear suspension at once as you don't want to be compressing those springs any more than you absolutely have to.
The one thing I am proud of on my 300CD is that everything works! The AC, the defroster, the sunroof, and even the power antenna. I t takes a while to sort out and restore each system but great fun to get it all working properly.

JHZR2 · #11 04-15-2022, 09:12 AM

Quote:

Originally Posted by carock

I bought an 85 300 CD California car three years ago with 245k on the clock. I bought the car because it was a single owner car, always garaged, and never hit, all in for $5500. The car's top speed was 75 mph and the steering had four inches of play. The windshield was sand blasted so bad it was difficult to drive at night.
I fixed the car up replacing everything in the suspension and steering. I paid to have most of that done as I did not want to mess with it after a nasty accident with a spring compressor on a Lotus Esprit years ago. Every bit of rubber in the engine compartment was replaced. The exterior seals were in decent shape and I am successfully preserving them with regular applications of Aero Protectant 303.
The biggest bummer has been the need to replace the engine. I did quite a bit of work to the original engine like replacing the front crank seal, the valve seals, and the injectors. It ran great for a few thousand miles. The engine developed a terminal head gasket leak due to corrosion on the block's deck surface. Had to pull the engine out and get it rebuilt by Metric Motors. This sort of head gasket failure is common on these cars at this age. Same is true for the V-8 gasoline cars. Every gasket is shot. Fortunately for me the tranny was rebuilt 12 years ago and it has given me no problems.
I have had terrible trouble with the new engine running hot. I tried every known coolant bleeding technique known to mankind on the internet. After two weeks and 9 separate experiments I finally got the temperature to behave by using a vacuum coolant filler and a drilled thermostat. I was just about ready to drive the car off a pier with that fiasco.

When looking for a 300CD I would purchase one based entirely on cosmetics. The mechanical bits can be bought, but all the cosmetic bits are NLA. Most of the mechanicals are in poor shape on these cars. You can rebuild them bit by bit and sort of perform a 'driving restoration" while you fiddle with it. It is important to rebuild the entire suspension and much cheaper if you do everything in the front or rear suspension at once as you don't want to be compressing those springs any more than you absolutely have to.
The one thing I am proud of on my 300CD is that everything works! The AC, the defroster, the sunroof, and even the power antenna. I t takes a while to sort out and restore each system but great fun to get it all working properly.

Agree with buying cosmetics on these old cars, the main reason actually being rust, then paint, and interiors.

I won’t touch a car with dash cracks. Plenty out there that are crack free, but lots of junk out there.

Agree that mechanical stuff can be replaced while other elements are either compromised or unavailable to replace. It’s a judgement call if compromised mechanicals, like your head gasket, which didn’t fail overnight, are worth the effort and money. For a rust free coupe, they’re rare enough that it’s the case. For sedans and w126 cars maybe not so much.

Finding a car with lower mileage helps a lot. And ones with records or one that looks well kept, not one that some dealer has sprayed all the oil off the engine, and shined everything up. Most folks don’t keep their cars like that. It can be a decent sign of hidden issues…

Everything on my car works too. Pretty neat to have a working survivor.