Buying a 1984 300CD that has been parked for over 20 years
 

Hi all,
It's been awhile. I haven't had a running 123/126/116 diesel in almost 10 years. I've always regretted selling my 79 300TD. I really loved that car, but I was mid engine swap (and other stuff) when we decided to move cross country. It wasn't worth it to bring it with at the time. I've always wanted a coupe and stumbled across one.

Grandson is selling it on behalf of the family. Grandfather, parked it in the garage over 20 years ago and it hasn't ran since. No one knows why it was parked. Grandfather passed away 3 years ago after battling dementia. Grandson tried to get it running about 2 years ago. Drained fuel, put a gallon of fresh fuel in. New battery. No starter engagement. Explored ignition swith to make sure wires were hooked up then gave up.

Cosmetically, it is in brilliant shape. I couldn't find any rust. Some scratches on top near the sunroof and may be a bit starting. Couldn't tell if it was dust/dirt from sitting or starting rust. One tiny dent in front right fender.

Looks to be custom wheels. Owner was an engineer for Boeing. My guess is he fabricated the Mercedes emblems on these rims. They look cool from afar, but on closer inspection they are flaking. They will need to be refinished or replaced. I like the way they look, so will likely explore refinishing.

Oil cooler line was wrapped. Must have been leaking or possibly had a motor mount failure and rubbed on belt.

I'm setting up a time to tow it home with owner's family. Then will get to work.

First plan is to get it on jacks and pull the wheels and bring them somewhere to see if they are salvageable. Then get new tires mounted. Then explore power to starter. May be a bad solenoid as to why it was parked? Or that could have happened during storage. Then dive in to what needs replacing and get it road worthy again.

Everything is there. Has original first aid kit and full tools. 1 small crack in dash above side of gauge cluster. Orignal carpet pads inngood shape. 194,000 miles on odometer.

First thing I did after my first move from eastern U.S. to SoCal in 1991 was buy a 1965 Chrysler. Lived its life from San Luis Obispo to Edwards AFB. Not a spot of rust, even behind the rear bumpers. Like finding gold to someone from the east. You quickly learn to first touch water fountains with your knuckles in the Mojave Desert, even in Summer. Glasses of ice water don't even need a coaster. No need to have drained the diesel fuel, unless it sat right by ocean fog. It can sit 10 years in SoCal without getting enough moisture to grow black-slime. Otherwise, diesel doesn't evaporate appreciably like gasoline does. Only problem buying a car from an engineer is that it may have improvements, using say parts from the McMaster-Carr catalog (or Boeing stock?) that would likely confuse a gomer dealer mechanic, even if a smart fix or upgrade. Those guys will prove useless anyway, just stating, "can't get that part".

Diagnosing "no crank" should be easy. Step one is verify the engine isn't seized. You should be able to turn it over by hand. I use the hex nut on the power steering pulley atop the engine, using a long 22 mm box wrench. Might need to tighten the V-belt or at least push on its side to keep it from slipping on the pulley. Otherwise, fuss with socket extensions to get at the crank bolt with just enough room for a wrench to the radiator shroud (or pull it up, just 2 top clips). There is no starter relay that I know of, just direct from key switch to contactor on side of the starter via NSS and little screw terminal in front of the battery. You can jumper the contactor there. It is the smaller wire going to the starter, so just jumper to one of the other two screws (both are BATT+, one feeds the starter motor cable). Even with an auto transmission, your year can actually be push-started if you get it rolling up to ~35 mph and shift from N to 2nd (read manual). That is because is has a rear pump, as does my 1965 Dodge Dart automatic (dropped soon after).

If the engine then turns over but doesn't start, insure the glow plugs are getting power. You should hear the GP relay clunk off after 20 sec. On cold days, you can cycle it again w/ the key switch. The dash light going out just predicts "glowed long enough for a new engine", based on underhood temperature, but glowing longer never hurts and can be required for a worn engine to start. I once rigged 3 glow plugs to BATT+ w/ jumpers when I had the GP relay out for repairs and needed to move the car. It wouldn't start without some heated up, even on a 70 F day. If it still won't start, verify the lift pump inlet filter isn't clogged (clear, or just change it since cheap). Might need to crack the top tube nut on each injector to let any trapped air out as you crank, especially if someone ran the fuel tank dry to get air into the IP. Before that, pump the hand pump on the lift pump to flow air bubbles out of the IP inlet supply. Any air will be compressible to perhaps keep the injectors from popping open.

I didn't drain the tank. It is the current owner years ago. The car is stock except the wheels. No 'engineered' parts. I have lived in CA for almost a decade now.

I was going to bring a wrench to spin the engine, but figured that may hurt my negotiations. So I chose not to. My initial thought is the starter solenoid, but like you said will be easy to diagnose once it is in my garage. Its possible the engine is seized, but seems like a low likelihood. Hopefully picking it up Friday.

Thanks for the tips. This will be the 5th 617 I've owned. I was the only person that worked on them. Never needed to bring it to a shop. I learned so much from this site starting nearly 2 decades ago.

Check the rear window glass for de-lamination on the bottom edge. A common problem on coupes and finding a new/used decent rear glass is almost impossible. Good luck. Looks like a nice car.

it's a center hit or a big miss opportunity without knowing WHY it was parked

carefully inspect for wire damage from rats.

the 123 coupes are awesome.

Yes, it could be a ton of work including drivetrain. The trans oil was super clean with no smell. The engine appeared normal. Definitely no visible wire damage.

The price I got it for, I'm minimal risk in to it. Could obviously cost a ton to refurb, but it doesn't need any cosmetic refurb, which is the part I would have to pay someone to do.

There had to be a mechanical reason why it was parked. Hoping it is simply the starter solenoid or a fuse/relay. We'll find out. I'll post progress.

Glass looks good. I didn't specifically look for this, but I don't recall seeing any issues onnthe glass other than a rock chip on windshield.

See if the engine turns before using the starter. Soaking the cylinders with Marvel Mystery or the like would be good for an engine sitting that long.

Sounds like a nice find, good luck!

Yep, good plan.

I just picked up a 240D that had sat for 15 years.
As you may expect, all mounts were shot, and all clutch hydraulic components too.
Also, there was a TON of diesel algae. Way too much to clean the easy way, I had to pull the tank and clean it manually. Not a big deal. I assume yours will be in similarly bad condition.

Good luck! Looks like a fun project.

The side rear window mechanisms can also be a problem on coupes. Also the sunvisors are coupe specific. Sedan/wagon sunvisors will not fit a coupe.

Check the hand primer pump as well. The seals will dry out and let the IP lose prime. Also, check the spin on filter. Some forget to refill the filter with diesel after replacing it and try to start the engine.

What’s the story here?

Thanks,

Luckily, I just went through some of my parts. Found 2 new Lemdorfer motor mounts and a new trans mount and filter kit.

Was yours sitting inside or out? Mine was mostly in a garage. Recently came outside under a cover.

Thanks, I will. Hand primer was old clear style. Fuel looked clear. Didn't try to pump it yet.