Sirs: Have an '85, 2.2L, diesel with multiple failures, probably instigated by the failure of the roller in the vacuum pump...the bearings sprayed to the four winds in that section of the engine, and these, interjecting themselves between gears and the chain, causing the alignment pin between the camshaft and camshaft gear to shear, and the rest is a diatribe of metal talking to metal in the worst way.
The ball bearing[one] that I recovered looked as if it had been on the bottom of the Colorado river for awhile...
Have any of you had a similar misfortune?
This trail of discovery has taken me some time to unravel.
A caveat...if any of your '84-'89 vintage 4,5,or 6 cylinder diesels sound a little rough...something that sounds to be in the chain drive, and that turns up negative, also inspect the pump.
Makes me wish the pump were electric, or driven by the fan belt!

My vaccum pump went in my '87 300SDL. My mechanic said I was lucky as sometimes the vacuum pump innards can derail the timing chain, get stuck in between moving parts and do all kinds of damage. But mine suffered no ill effects.

Lucky, indeed...
There are two races in the follower-roller in the pump...maybe 24 balls total. Only recovered one! I suspect one or more got between gears and the chain and, well...that's why I'm asking in another thread about a salvage motor I was holding in reserve.
I am not impressed with the engineering, or the longevity of this highly pampered engine of mine.
I am considering an Isuzu npr diesel...anyone out there have experience with Mercedes vis a vis Isuzu?
I have been reluctant to invest in Japanese motors, but the reliability has been legendary. My aversion starts with the bolts...I don't like the looks or feel of the bolts. Crazy, yes?

A minor follow-up...the element that retains the ball bearing cluster is some sort of plastic/nylon...there is sufficient room for roller bearings...or needle bearings, either one retained in metal keepers. This part, when one thinks of the strange service stresses, should be of higher quality.
I have owned five Mercedes machines, two of which I currently own- both broken! I think I will look elsewhere for reliability.
Any opinions as to the most reliable machine? I am not a performance driver, but I do appreciate safe handling and sure tracking.

I would not consider a failed vacuum pump bearing indicitive of poor engineering. Infact, I believe that in the long-run, a properly maintained German car will outlast any Japanese car (though the Jap cars are less maint intensive for their life) and with more style; especiall a w123 with a 617 engine.

As you can see, a vacuum pump failure is neither common, or rountinely catastrophic to the engine on average. It seems to me that you just got a hint of bad luck.


By the way, how many miles are on your now broken MB?

ATLD

Dear ATLD,
Thanks for the reply.
The beast has 175k miles,98%of which is highway, under 60mph, oil changed every 2500 miles since new.
The engineering is not fail-safe. As I stated, roller bearings would give better service under these conditions: additionally, the "cage" that isolates the pump from the timing gear could be screened or designed to hold the ball bearing in the eventuality of a bearing failure. This failure has probably destroyed my engine.
Why not run the pump off of the fan belt, for example? Sticking the vacuum pump where it is makes access to the injection pump all the more difficult...speaking of which, to change the oil seal at the anterior of the injection pump, one is almost forced to remove the oil filter housing...real smart.
As I stated in another thread, engineers in my day were required to take shop/practical classes to better understand the logistics of repairing and servicing what they'd just designed.

This happened to a friends' '85 190D. He bought the car at auction for $600, with a perfect body and interior but the broken vacuum pump was laying in the trunk. He brought me a used pump to install but he didn't want to do any major engine dissassembly. I told him he was taking a gamble if the P O didn't get all the old fragments out. The car ran flawlessly for 3 weeks until something wedged between the gear / chain and timing cover, breaking out the chunk that holds the serpentine fanbelt tensioner. The car still runs but can't be driven. I agree that a belt driven pump would have been better. I've gone over 160,000 miles in my '87 Isuzu pickup with very few problems but it's gas, not diesel. Isuzu sold far fewer small diesels here than Mercedes so parts may be a problem. Also, I believe, the small Isuzu diesel (like my gasser) uses a timing belt which must be changed regularly or bad things will happen!

Happy Motoring, Mark

__________________
DrDKW

I understand,
Maybe it was a bit stupid to power the vacuum pump off the timing chain, considering that is a bearing failed, they would migrate to the chain and gears. But understand, how many other cars can even get to 175,000 mi period. I have several MBs (1 diesel), a BMW (maintenance nightmare), several Chrysler products and a Honda. The other cars are no competition for the MBs in reliability. One of my Chryslers has 70k and is on its 3rd transmission, 4th starter, 2nd head gasket, 2nd water pump, 2nd belt idler... and so forth. My MB diesel required no engine or accessory work until it hit 185,000mi (and that was a water-pump that cost $27) other than standard maint and wear parts. Thats a record that I cherish. If something happened to my diesel now, I'd still say I got my $ out of it. Nothing ages like a Mercedes.

As for my Honda, being the 2nd Honda I've owned, all I can say is that they are good reliable cars, and probally a steal if you can find a decent one used. They age gracefully and usually not problematically for the first 100k or so. However after this, I found so amny failing components that I had to junk it. The Honda I have now has about 50k and has had no major problems as of yet. I won't EVER buy a Lexus.

What other Mercedes do you have that's broken?

Anyway, good luck car shopping!

ATLD


By the way, as an Engineering, I can tell you we do require future engineers to get actual shop time. It's required in the curriculum.

Thank you gentlemen...atld and Dr? Silvestro...
Actually, I have a love/hate relationship with this machine...I vascillate between rage and mourning.
We also own an '85 190e, which had lingered for weeks before dying...a proper death.This needs a new/salvage engine. I purchased it with 140k, and it now has 170k. The 170's are not good at our house. I don't enjoy pulling motors...not my line of work.
I don't care for the new models, and, yes, atld, I agree with you that these hold up very well, generally. Whenever I take my wife to test drive a new car, she states that she prefers her old car!
Glad to hear that some schools, at least, are still requiring shop time. The two closest to me do not,
Still, in terms of reliability, the '64 122s Volvo was remarkable...gear driven,push rod, cast iron. Easy access. This machine I definitely did not pamper. Perhaps a lesson there?