123 300D turbo purchase advice, please? - PeachParts Mercedes-Benz Forum

dbn1066 · #1 03-12-2007, 01:42 PM

I'm going to look at a 1982 300D turbo later and would like some quick advice as to what to definitely check out on these models. I have ownly owned 115 diesels and am pondering a 123 for the first time. Here's what I know so far: Georgia car till recently (i'm in Pittsburgh), no rust (supposedly), no winters, garage kept always, interior no cracks or fading except for dash, present owner bought it from elderly second (or third) owner and knows nothing about Mercedes but thinks it will need a timing chain (what are the symptems?), no real maintenance records, 226k, no known rebuilds, etc. ivory ext., blue int. Fellow says it runs great, but doesn't want to use it as far out in the country as he lives- horrible roads, etc (mile long mud-n-rut driveway). Can a car this old be carfaxed? Any advice would be greatly appreciated!!!

bgkast · #2 03-12-2007, 01:59 PM

Carfax should work. Rust is the big thing to look for. 226K is about the time you consider replacing the chain, but the only way to know is to check the stretch, and that is not a real fast thing.

winmutt · #3 03-12-2007, 02:57 PM

Jack points at the easiest way to spot the rust issue. I have never seen a car with good jack points and lots of body rust. Also if you can take a look at all the rubber bushings in the tire well. Also make sure you get it on the highway and that it is shifting thru all gears without flaring etc.

hitwtom · #4 03-12-2007, 03:12 PM

I recently bought an '82 300D Turbo. No problem getting a report from Carfax. Like everyone else has said, check around the jack points for signs of rust. If you can, pull up the floor mats and check the floors for rust. Check after a rain if possible to see if anything inside is wet (could be anything from a clogged drain to a leaking sunroof. Vacuum system

Do the doors lock, engine shut off etc. Heater controls(CCU) does everything work? Hope this helps some.

patbob · #5 03-12-2007, 04:07 PM

Drive it down his mud-n-rut driverway if you can.. check that it steers OK and doesn't pull in strange ways, especially over sharp-edged bumps that affect one side but not the other. Do some fast cornering and see how it feels. My car doesn't do well on these sorts of things, and all I have to go by is a general gut feeling that it should do better... with your experience, you probably know what it should feel like.

Check the tires for wear. It's an oldie, but a goodie. If none, check they are all the same kind/size :0 (size? Yeah, seriously). Worn suspension parts cause uneven tire wear, and sometimes POs put any old tire on to hide the problem.

Check for fuel leaks under the hood. With the ULSD and people trying bioD in these cars, there's been a lot of leaks reported on these older cars. Injector line seals, primer pump and returns lines have been typical problem areas. My return lines leaked so bad I trailered mine home.. amazingly, commonly available vacuum line doesn't hold up to the heat & diesel too well.. the PO kept trying to replace them to fix the problem and it never worked for any length of time.

Check that the climate control system works. Not just that the AC gets cold, but that the air comes out of proper vents on the appropriate settings, and that you actually get hot air out. ACC system failures are a pretty common problem.

From what I've read, I'd also check for leaking oil cooler lines. Apparently, they can suddenly let go and kill the engine ultra fast.

If you get the chance, hire someone to do a compression check. My indie claimed it was fairly common to have low compression on cylinders 4 & 5 (ones nearest the firewall) because the engine overheated at some point. His claim was that 4 & 5 get the least slipstream cooling and get cooked.

And there's the ever popular blowby test too.

And it'd be nice to know that you'll be geting both the master & valet keys with it

Preferably in steel and not brass (although I have had no problems with my brass key).

If you can, have the PO explain the operation of the door lock and ACC systems. I've had to read the FSM to understand mine because the owners manual is a bit too vague and I didn't think to do this. Of course, if you don't know how they are supposed to work, you'll probably be unable to evaluate whether they are working perfectly or not.

Incidently, I find it interesting that the owner is getting rid of the car because of mud & ruts. My 300d, even with all its faults, is the best vehicle I have for going over ruts and bumps (although it does tend to slip and slide in the mud a lot). That awsome w123 suspension allows it to cruise over speed bumps and potholes smoother than any other car I own. I'm comparing it to an 84 volvo and a 2000 expedition.

Hope this helps, but if you check everything everybody suggests, it'll take you all day

dbn1066 · #6 03-12-2007, 04:35 PM

Thanks guys, I'm off to look at it now and will let you know....BTW he's asking $1500...

dbn1066 · #7 03-12-2007, 09:05 PM

The car has NO rust. Almost unheard of around here. It came to Pa from Georgia in 2000 and never saw a winter or sat out- i.e. no salt. jack points are perfect as are all areas of the rockers, wheel well flares, etc. Floors and trunk are bone dry and solid as the day it was born. Interior is dirty but in very good condition, as if no seat but the driver's was ever used. Dash has cracks and some of the wood pieces are cracked, piece above center of console has fallen out but is present. Sunroof works and does not leak, windows work fine except pass. rear. Door locks work. Heat works but a/c doesn't kick on and blower seems to only have one speed-low (but niether myself or PO now how to work them exactly- do you push the on fan button more than once for higher speed?).

Steering and handling seem fine- no noises or pulls. Brakes will need attention but care stops fine, good pressure. Shocks will need replaced but the car handled the 'country roads' just fine, I was impressed. Rubber suspension bushings looked ok but it was hard to get a good look.

Auto transmission seemed to shift fine: 1-2nd around 15mph, 2-3rd around 30-35, and 3-4th around 40-45. My research says this is normal? Shift linkage may need adjusted as the shift lever doesn't stay on the D- falls down one.

Engine: Started and shut off as requested although a noticeable knock and rough idle when warm (engine shakes @ idle but not violently)- worries me a little as I don't know enough to diagnose this. However, there is no knowledge of the last valve adjustment and the timing chain is due to be changed; don't know about the IP but oil level in it was good- timing may be off? A good tune-up and thorough fluids/filters change + fresh diesel are in order. (Car has not been inspected or driven since '02). There was no evidence of fuel leaks. IP was dry and bloc, head, and rest of the engine bay was clean except for oil residue from oil fill cap (looked like an after market replacement with bad seal). Compression seemed fine as engine had plenty of power. How do I check for blowby? And what exactly is blowby? Some have told me its a non-issue, I don't believe it is. Please forgive my ignorance on this issue...

Also, I am not familiar with turbos but I know enough to tell that this one's seemed to kick in just fine!

Well, thats the gist of it. I think it seems like a good deal @ 1500. Thoughts? Answers? Thanks for your time.

Sbean · #8 03-12-2007, 10:09 PM

Blowby is pressure from the combustion leaking past worn piston rings and escaping into the crankcase and valve cover. From there it is carried through a hose to the air cleaner and sucked into the intake manifold. The quick test is to loosen the oil filler cap with engine idling and watch what happens. The more the cap jiggles and bounces around, the more blowby you have. Try plugging the hose to the air cleaner and see how it affects the cap jiggling. Steve

winmutt · #9 03-12-2007, 11:03 PM

Quote:

Originally Posted by dbn1066

Heat works but a/c doesn't kick on and blower seems to only have one speed-low (but niether myself or PO now how to work them exactly- do you push the on fan button more than once for higher speed?).

Heat works in defrost mode only? only ran at high? Did the ac kick on when the defrost was running?

dbn1066 · #10 03-13-2007, 06:26 AM

Basically it seemed that heat came out thru def, vent, and floor, but fan speed was low- only, unless I didn't know how to work it. a/c compressor wouldn't kick on at all.

I can figure out more if/ when I get the car home soon. I've convinced myself to buy the car. I don't want to pass on a rust free car with good interior and that runs decently!

cessna5354 · #11 03-13-2007, 06:55 AM

Fresh Diesel will be in order as you said, however you may have to clean the tank strainer. I had one sit for 5+ years, and it ran for 2-300 miles until the tank strainer plugged. The power of the engine deminish till you just barely crawl. New filters, hoses, and clean strainer and you could be good to go.
Best of luck,
Gary

toomany MBZ · #12 03-13-2007, 07:18 AM

The CCU is a common failure. Heat, fan speeds erratic. The fan has three settings, high, automatic and low. Checking compression, will also give you a clue to cylinder leak down. Follow cessna's advice on fuel filters. Strainer can be a bear to deal with, but if ya gotta, ya gotta. Valve adjust good move. Shift lever not staying in place is something I have not come across. IP timing failure, rare. You will need to check timing chain stretch. Symptoms include sluggishness low power, overall poor performance. Sometimes difficult to tell on 25 year old diesels, yeah, I know.

bgkast · #13 03-13-2007, 01:24 PM

Sounds like a good buy.

patbob · #14 03-13-2007, 03:42 PM

sounds like a good buy to me too... better condition than mine was in when I bought it.

ACC sounds typical from what I've heard. Top fan button is high, bottom is low, middle is auto. Rough idle could just be lack of use or something easy to fix, or could be more serious. Blowby is an opinion -- none (is that even possible?) is best, some is OK, so much you can't start or run the car or it runs away burning motor oil is bad -- as you can see, "some" leaves a lot of ground for interpretation on whether any given car is closer to best or bad

Sorry for droning on earlier.. didn't realize how much I had typed.

dbn1066 · #15 03-14-2007, 07:11 AM

Thanks all for the input! Should have her here next week or so. my first 123....