Hi!

I searched through the old posts regarding idle shake idle shaking dampener rack, etc.

The problem is that my car shakes side to side only once the engine is warm. It was really bad one day when it was hot. I thought it was the temperature. However after two bottles of the cheap STP Diesel 'stuff' it got better.

The thing that I still hope for is well "bad fuel quality" because it didn't do this before. Only after that full tank of 'new' diesel fuel.

I ran a full bottle of RedLine DFC through it and it isn't bad now however it's still there. Strange thing is that it does it only once in five or so occasions (at traffic lights, jams, etc.)
At other times it could be silky smooth.

I have come to these conclusions...

1. It could be caused by a low compression in one of the cylinders? I do not think it is because the engine is so strong (I think at least) and I did that "diesel test" by building up the pressure and letting the engine choke and die.. - my engine died in about 10/11 seconds.

2. most people think it's rack dampener bolt. I tried to look for it. I found something near the oil filter at the back of the injector. Does it look like the drawing i attached? I tried to move it but I couldn't move it either way so I left it alone. Is it the right part?

It looked screwed in and there is a small gap (about 1 to 1.5mm between the big nut and the small nut).I'll play around with it tomorrow, but I can't do anything today.

3. Engine mounts? I tend to believe that I need to replace 'em only when the engine shuts off hard and makes 'metal-metal' sound when it shuts off (It did with the W124)

4. Engine shocks? I never heard of 'em... I'll ask this guy at an MB shop on Monday about it. See what he thinks.

5. Valve adjustments? I'm going to get this done anyway.


Am I missing anything? I'm sorry to post this again. However i think it's not too bad since I think I've summed up what most people say about "rockin' 300ds"

The fuel return lines are also leaking (I'll replace 'em on Monday), could that be it?

I'll play around with the rack dampener tomorrow and I'll update it. I figured that I need to loosen the bigger nut before I can adjust the smaller nut.. but I could barely see now.

Cheers,

Attached Thumbnails

 

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2008 BMW 335i Coupe

Does the engine tilt to a fair degree to one side when you put it in gear? If so, I'll bet money you need new engine mounts. My girlfriend has a POS '88 Ford Taurus, and whenever you put it in gear, you hear a nice loud CLUNK 'cause the engine hits and settles on the rear mounts (I'm assuming the rubber's trashed).

If the engine doesn't do that, however, I still wouldn't rule out the possibility. One thought, since you mentioned that fuel additives seem to clear the problem up some, would be to pull the injectors ans get them cleaned and tested for proper spray. Also, how are your fuel filters? The bad quality fuel is a definite possibility...maybe run the tank as empty as you're comfortable with, refuel, and change the filters just to be doubly sure.

Getting the valve job done would be a really good idea, as well...

Just some thoughts...good luck!

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2001 VW Jetta TDI, 5 speed, daily driver
1991 Ford F-350, work in progress
1984 Ford F-250 4x4, 6.9l turbo diesel, 5 speed manual
Previous oilburners: 1980 IH Scout, 1984 E-350, 1985 M-B 300D, 1979 M-B 300SD, 1983 M-B 300D
Spark-free since 1999

I would think that you could check the engine shocks by disconnecting them and see if it makes any difference. If it shakes even more they are probably ok. If it doesn't make a difference, perhaps this is your problem. They are two, no?

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Ed
1981 300CD (Benzina)
1968 250 S (Gina) 266,000 miles!
1983 Alfa Romeo GTV6 (Guido)
1976 Jaguar XJS-saved a V-12 from the chevy curse, what a great engine!
1988 Cadillac Eldorado (better car than you might think!)
1988 Yamaha Venture (better than a Wing!)
1977 Suzuki GS750B
1976 Yamaha XS 650 (sold)
1991 Suzuki GSX1100G (Shafty Gixser)
1981 Yamaha VX920RH (Euro "Virago")
Solex Moped
1975 Dodge P/U camper


"Time spent in the company of a cat, a beer, and this forum, is not time wasted!"

I bought the Haynes manual and I have not seen reference to the engine shocks, let me check again.
I'll give it a look.

I'll do the valve adjustments first on Monday and ask the shop to check the engine mounts. If they look like they need to be replaced, I'll replace 'em as well. I really can't tell...
Since you mentioned that the injectors need to be cleaned, I think I'll leave that to myself and some Diesel Purge (when I have time... )

I've changed the fuel filters and it made little difference if nothing.

Right now I'm just running the car until the orange fuel warning light comes on. Then I'll make a run to the 'gas' station.. I hope it makes it :p

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2008 BMW 335i Coupe

ordered some diesel Purge, I hope that'll help.
I don't think I'll 'purge' the injectors until next week though (hopefully new tank of fuel)

It's soo hard to waste 'gas' on this car! I drove so much today, hard acceleration, city driving, etc...
If I was driving a Taurus, it'd be soo easy..

Any help on the rack dampener screw?

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2008 BMW 335i Coupe

If you have no record of when the engine mounts were last replaced, change them. The rubber gets hard as it ages and no longer absorbs the rocking motions of the engine. They are cheap - ~$15 or so each, I think - just change them! Do the tranny mount too while you're at it, it's not hard. Do NOT wait for clunking noises!

I've been told the engine shocks are there mostly to limit the shake when you shut down the engine, and that they don't really affect normal idle shaking (that's what the engine mounts are supposed to do). The shocks & shock mounts are expensive - only change them if they are bad (remove them & pull in & out to test - should give resistance.)

Valve adjust is a good idea (should be done every 15 or 30kmi, I think). May not help the idle though. Diesel Purge will only help if injectors aren't clean. If they are worn (nozzle needles) then all the cleaner in the world won't help, you'll need to have a shop rebuild your injectors ($100-250 per set). No, the leaking return lines won't have any effect on idle quality. The rack damper bolt wouldn't hurt to repace with the updated style (yes, it's the thingy you're looking at by the oil filter can), however be warned that getting it adjusted properly can be VERY tricky! And even then it may not cure your problem.

I still think motor mounts are the first thing to do...


Regards,

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The guy at the shop that I go to told me that someone did the Valve adjustment already so he didn't touch it.

Instead the engine mounts and tranny mount were replaced (they were worn out)

I read somewhere that someone replaced his engine mounts and forgot that he was driving a diesel. I'd say the same...
except for the clatter when it comes to a stop. It's soo o smooth now....

the rack damper screw has also been upgraded according to him..

What started as an engine shake problem lead to him finding a leaking brake line or something like that. That got taken care of too...

just an update.

so if you're ever in doubt and the car vibrates too much then replace the mounts...

It even shuts off differently now...

cheers,
-Holson-

Thanks for all the suggestions though.

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2008 BMW 335i Coupe

an update...

The engine mounts made the car nicer as it doesn't shake as badly as it did before, but it does shake horizontally still.

It bothers me a lot in traffic. However today I played w/ the STOP lever on the engine. When I pushed the STOP lever by just a bit,

I could easily see that the amplitude of the engine's vibration was lower.

Not to mention that it's smoother in gear than in Neutral/Park (before the mounts, filter, rack damper, it was the other way around)

I decided to lower the idle.

In case you're wondering how to do that... There is this flat head screw on the diesel injector secured by a 14mm lock nut at the base of the screw. If you use a deep socket and an extension you should be able to unscrew it.

I lowered the idle by more than a full turn. I also realized that other diesels (300SD, 300D,etc.) that I've seen seem to idle at a lower engine speed than mine.

The idle was sooo smooth! I took it out for a drive and I couldn't believe it! I thought my compression, etc was bad. However, I ruled it out because the engine starts so easily.

The only problem now is that if I rev the engine (in neutral) and release it, the idle seems to dip enough to make the air filter cover vibrate (metal rattling). I played around with the linkage just to find that the linkage has so much play.

Is there anything that I can do to reduce the play? As in make it tighter? If I could do that then I'm going to reduce the idle back to where it was so smooth that I couldn't believe it. (I raised the idle a lil bit because of the rattling)

BTW, the throttle linkage is soo complicated...

I hope that helps some people too!

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2008 BMW 335i Coupe

I'll bet you a dollar that one of your air cleaner mounts is broken!! Take a 10mm socket and remove the entire air cleaner and check each rubber mount. They are very cheap. I thought all mine were good until I took the whole thing off for another job.

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Orland Park, IL
1985 300SD 215,000 miles

Bad motor mounts will break your air cleaner mount. I made some notes when I replaced the motor mounts in my 82 300d.
It has been some time since I did this, coments welcome.

The 300d has 3 mounts. 2 located on each side slightly back from the front of the engine and a single rear mount at the aft end of the transmission.

Front motor mount replacement:

Each mount is secured from the bottom by a single 10 mm threaded allen head bolt (8mm head) located in a recess.

Removal and installation:
Raise the car for access. From under the car, remove the allen head bolt with a 8mm wrench. Using a jack, lift that side of the engine several inches. That will raise the mount arm off of the mount. From under the hood, remove the mount shield by working it out. Note the orientation of the shield. If the shield is hard to move, lift the engine with the jack a little more. Once the shield is removed it will allow access to 2 small allen head bolts that retain the mount. Remove these with a 4mm wrench. Remove the mount, noting the orientation and replace it with a new one. Reinstall the small allen bolts and the shield. Lower the jack, being sure the shield is aligned. From the bottom of the car, reinstall the allen bolt (t may be necessary to lever the engine slightly to align the holes.) Repeat the process for the other side.



Rear motor (transmission) mount replacement:

The single rear motor mount is located at the aft end of the transmission. It is supported by a brace that is held by 4 bolts (17mm heads) to the chassis. The brace has 2 bolts (13mm) heads that attach the mount to the brace at the bottom.

Removal:
To replace, lift the car for access and support the transmission at the aft end with a jack. Loosen the 4 (17mm) bolts and the 2 (13mm) bolts slightly, then remove the 2 (13mm) bolts that attach the support to the mount. Then remove the 4 (17mm) bolts, and remove the brace. Lower the transmission slightly (careful not to lower too much) to access the 1 (19mm) nut that retains the top of the mount. A 19mm box end wrench will work well here. Remove the nut and the mount will fall off.

Installation:
Install the mount using the 19mm nut at the top first and tighten securely paying attention to the alignment. Raise the transmission slightly with the jack. Start all of the bolts holding the brace to the chassis and the mount to the brace then tighten securely.

82 300d 194k

This problem is long gone!
Thanks for all the input, I did check the air cleaner. It's allright now, tightened bolts here and there... :p

The engine is very smooth now, well not LS400 smooth... but very nice for an old diesel I think. I also ran a can of diesel purge yesterday.

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2008 BMW 335i Coupe

Sainttammany,

I was changing my transmission and differential fluid last night and noticed one of my engine mounts has started to deteriorate. I found your nice write up on changing the mounts. Thanks. What type of jack did you use and where did you jack it from? I didn't have time to look at it long, but the mount arm didn't seem to have enough room to jack from and maneuver new mounting hardware in place.

1983 240D 150K 4sp manual

John M,

I recommend you put a couple of pieces of 2x4 on top of a hydraulic jack and place it under the oil pan, favoring the side you are removing, and jack the engine up. If you only do one side at a time it is easier to get the new mount in and line up the threaded hole in the aluminum strut with the through hole in the mount so you can get the screw back in from below.

When you jack the engine up, remember the suspension will move up as you take the weight off the springs. So, to get an inch or more clearance you need to jack the engine up quite a bit. I did the job last summer and found it was easier if you got the metal shield out of the way so you could get a wrench on the driver's side screws you get at from the top. To get the shield out of the way you need to unscrew the single screw from the bottom and jack up the engine until the aluminum strut to the engine clears the shield enough so you can pull it out.

Edit: There is also a snubber mount at the back of the engine/front of the transmission that has to be removed to allow the engine to move enough. My 240D is a manual transmission and I suspect your car will have the same thing. It is a pretty simple mount, just a couple of large (19 or 17 mm bolts) fasteners. I replaced mine as the rubber in it was mostly the consistency of tar. It was less than $20.

Good luck, Jim

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Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)

Jim,

Thanks. I'll be a few weeks before I tackle this. I can't say I have any vibration yet but after seeing the tear in the rubber it can't be too far away. BTW, I took your advice and installed Redline MT90 in the manual transmission. I can detect a tiny improvement in operation over the ATF even though it operated fine previously. Thanks for the tip.

1983 240D 150K 4sp manual