I recently purchased an '85 300D and have a few questions. BTW been a long time diesel owner had an '82 Audi 4000 diesel as my daily driver until a pickup totaled it end of last year. The 300D needs a few things, turbo drain seals, Valve Cover Gasket, A/C not working, shocks, vacuum leaks holds just enough for the door locks to lock once maybe. So far this site has been a great learning experience. So to the experts here.

The engine has a pretty good shake at idle, I've read about the rack damper adjustment and have not done that yet. I have cracked the injector lines at the injectors and cylinders 2 and 3 seem to have less an effect on idle speed than the rest. I've done the starter current draw compression test, amp draw looks to be +/- 10% on all cylinders. I have slowed the idle speed down by slowly pushing on the stop lever, as the engine slows the shake diminishes. I can get the engine running slow enough where you can distinctly feel the individual cylinders fire and they all feel about the same. There is a louder diesel ignition knock on cylinder 2 and it goes away when you crack the injector line. From the tests I've done I feel the engine is in pretty good mechanical shape. Once off idle the engine doesn't sound like it has a dead cylinder. Seems to have pretty good power, but my Audi had the VW 1.6 N.A. in it. Doesn't feel as quick as my '96 F250 with the Powerstroke but not bad.
Questions:
1. How are the Bosch injectors in these engines current mileage estimate is 240K - 260K. Should I consider changing them all.
2. How much of an effect will adjusting the rack damper make. I've read that these engines aren't the smoothest at idle speed. Right now the shake is bad enough to shake the car at idle in drive.
3. There is also a high pitched whistle from the turbo just before it starts to build boost, primarily happens between 1700 and 2200 rpm. Best way to describe it is: When accelerating the transmission will shift and the rpm drops, I will get the whistle until the rpm build and turbo speed increases. If I get on the go pedal and add fuel the turbo will spool up quickly and the whistle goes away. Am I looking at a turbo failure soon?

About to start the repair process, before I start putting money into parts, what do y'all think.

TIA

Charlie

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85 300D, 96 F-250 CC PSD, Farmall 656 D and other assorted gas powered stuff

Hi Charlie,

I'm pretty new here too, but I would suggest looking at the condition of your motor mounts and the little shock absorbers that are attached next to the mounts. My 82 300D had exactly the same symptoms as those that you are describing. Bad mounts will be pretty obvious if you take a good close look at them. Probably flattened out and greasy, the shocks can be disconnected at one end and worked back and forth. No resistance equals a bad shock. If this is your problem, the job of changing everything that I mentioned is not a big deal and has been documented here on the website.

Tom

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1993 300TE
1984 300D
1984 300SD
1976 BMW R90S

I wouldn't change out any parts until I did a valve adjustment. It's free, and if you are not the anal type you can reuse the gasket if it's not toast just remember to replace it outright next time you do the valves. But a new gasket is only around 10 bucks or so. Your turbo acts just like mine- I believe there is a leaking gasket or hose somewhere. It's not supposed to whistle like that from what I've read here. Don't worry about it yet, if it's boosting you're OK for now. Check boost pressure by teeing into hose from firewall to ALDA and running the hose to a pressure gauge. Run the hose through the engine compartment drains, outside the car, and into the driver's side window. Go find a hill, go WOT @ 4000rpm, see what the gauge says. Should be around 12 psi. Check the ALDA line and banjo bolt for obstruction, check the switchover valve at the firewall for correct operation. My car's switchover valve at firewall was dead and my manifold boost pressure sensor was also dead when I first got it leaving me with no fuel enrichment and wondering what the hell was wrong but this site got me on track. If the ALDA has not been molested, don't molest it. Try to recover your power through other means first. Injectors are widely considered to be ready for replacement at 100k but a lot of people get more miles out of them. Just depends on PO maintenance habits. Since you have over 200k you should go ahead and replace them if at all possible. May want to try rebuilds from TomJ. I did and my car runs really good. Also got an extra set for ten years from now!
Rack dampers are around what, $50? Change it out, along with the motor mounts if they have not been changed. Your ACC belts get closer and closer to the oil cooler hoses as the mounts flatten out and you know what that means. A lot of people report a huge difference when the motor mounts are replaced, I didn't notice much in my case. Mine were definitely toast though.
Do a purge too. Might help might not but it's easy and cheap.
New injectors, new mounts, valve adjustment and lastly a new rack damper would be I would prescribe for your car.

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'02 BMW 325i
'85 300D 450k
'93 190E 2.6 170k(killed by tree)
'08 Ducati Hypermotard 1100S 6k
'06 Ducati S2R800 14k(sold)

i would not change injectors blindly. good chance with that mileage theyve been changed already. if you think you have a problem with them pull them and get them tested. i have changed a lot of injectors through the years chasing various problems. they seldom are actually bad. also find someone who is experienced with 300s and have them observe the idle, they bounce quite a bit with an automatic tranny. wont hurt to check the mounts etc as noted above. if they havent been changed the're prob ready.

good luck benz diesels are the best.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

I almost bought an "H" about 4 years ago, but ended up with an 8N instead. Best little tractor I've ever had, and my most beloved mechanical device. Sold it a couple of years ago. The "H" was propane, by the way.....

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Jimmy L.
'05 Acura TL 6MT
2001 ML430 My Spare

Gone:
'95 E300 188K "Batmobile" Texas Unfriendly Black
'85 300TD 235K "The Wagon" Texas Friendly White
'80 240D 154K "China" Scar engine installed
'81 300TD 240K "Smash"
'80 240D 230K "The Squash"
'81 240D 293K"Scar" Rear ended harder than Elton John

Jimmy,
Operating a propane (LP) powered tractor can be a real PIA, but the propane burns so clean I've opened up old LP fueled engines and they are real clean inside. Buy an old LP fueled tractor and convert it to gas, pretty easy. BTW I have 2 H's (1 apart), F12 in restoration, and a Cub 154 Lo Boy.

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85 300D, 96 F-250 CC PSD, Farmall 656 D and other assorted gas powered stuff