I have a 1990 300D that has no oil pressure at all. My dad was driving the car one day, and he called me to tell me that the engine shut off at highway speeds. I went out to help resucue the car, and found that it would not turn over. After a while, it started to turn over to the point it would idle on its own but with no oil pressure. I pulled the filter with it running, and no oil was being delivered, as well no oil to the cam. There are no external leaks, so I think it must be the pump, oil pressure valve, or the pump drive chain.

I am going to replace the motor with a used one that I have yet to purchase. I am not sure what caused the failure, but was interested in finding out if the oil pump can be pulled and replaced without removing the engine from the car. If it is possible, I was thinking about puting a new pump on it and seeing if the thing will come back to life. If it does not work, I would still be able to put the pump into the used engine.

I noticed the oil pan is not like that of the om617. It does have a side cover though. Is it possible to check anything from that, or am I just wasting my time?

If the engine shut down at highway speed as a result of losing oil pressure it is HIGHLY likely that the engine is toast and you would be wasting your time by replacing the oil pump.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I took off the side cover on the oil pan and found the pump chain in the pan. Anyone have any ideas why the chain would fail? The pump seems to turn fine.

I also found huge amounts of metal flakes in the pan. I suppose it is time for that used engine.

As we go down this road , I am hearing of more failures.
The chain is "rinkey dink" compared to 617 O.P. chains.
The Mantra "Lack of Maintainence" will be the first "Smoke + Mirrors"
approach.
At some future point (Who am I kidding, vehicles out of warranty in
the Decade[s]) I envision the chain + sprocket being declared
"Maintainence Items" by the "Gnomes of Sindelfingen"

Mine quit on the P.O. @ 167,000 miles.

My car had 280,000 when the op chain let go. It ran like new, never leaking or burning any oil. It is a shame, since the chasis is like a new car. I may have found a source for the engine, but if anyone has one I may be interested still. I am in the Atlanta area.

Thanks.

I have a 1987 2.5 Turbo engine w/ about 200Kmi on it. This is similar to your early 90's engine but without the computer controlled boost. I consider it a better engine because there a fewer electronics to go wrong.

Its currently sitting in a parts car I have that is towable (you can buy the entire car) or I can remove the engine.

I'm in Nashville which is pretty "local" for this kind of deal.

Email me at md21722@yahoo.com if interested.

Thanks,

__________________
Brian Toscano

If you replace the chain + sprocket(s) [as a diagnostic tool, depends on the
R.P.M.s the engine was turning when the O.P. quit...If the motor was at idle
there is a chance of no damage from lack of oil pressure]

In any case you're looking @ a "rebuild" opportunity (D.I.Y. , Metric , Noels)
(2k-3k , 6k-7k , 5k) to do the job right and motor on for another 200k.Or the
used engine route [Yes! I would replace both Timing and Oil Pump Chain(s),
guides , tensioners and sprockets....cheap insurance].Or a "short block" from
Mercedes (5k)

Has anyone here ever installed a warning buzzer to alert you at the moment the engine drops pressure say below 1 bar?

It may be possible if warned just in time, that you may be able to shut the engine down to save it!

I'm scared enough now after reading about several pump chain failures to seriously consider installing a low oil pressure warning buzzer system in my 87 300d, heck they are available for most commercial applications, why not my Benz too?

Do a search. It's been discussed in the past and a number of forum members have installed warning buzzers. One of the threads had a lists of parts and numbers. I think the buzzer came from Radio Shack.

__________________
1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

Has anyone as a pre-emptive move replaced the chain and pump, how difficult, how expensive, mine just ate a vacumme pump at 175k, I wished I had replaced it prior to the failure.
Ron

C.R.,

P.O. ("trusted Indie") replaced both on mine [unfortunately other damage
was done , yet to be repaired :Which is why I got the 124 so cheap)
If I recall correctly you must loosen motor mounts and raise engine to get
bottom oilpan off to gain access.
I've never heard of an oil pump failure , it's always been the sprocket and/or
chain.
If you've got a 2.5 with over 100K, I would surely consider replacing chain +
sprocket(s) cheap insurance.

The vaccum pump is a whole 'nother issue.[must be solid titanium with
hand cut natural diamond bearings] (Price).

C.R.,



When your vacuum pump failed was there any warning or ancillary damage?

No warning, I was driving down the highway and the brakes became very firm and almost completly ineffective, trans shifted harshly. There was no noises no warning.
I believe I was lucky on the colateral damage. Pulled the oil pan side cover and found ball bearings and lots of metal shavings, the pump suffered a catastrophic failure, the roller and cam were broken.
Fortunetly none of the material found its way into the timing chain. All material was recovered in the oil pan. Flushed engine with oil, changed filters, using a magnetic oil drain plug. Car still runs excellent.
Ron

Original vacuum pumps (those WITHOUT screws on the cover) were known to catastrophically fail. The revised model, with screws on the cover redesigned the bearing so it would NOT drop ball bearings into the motor.

Brian

__________________
Brian Toscano

md21722,

feedback:
old style pump (without screws on cover) may fail horribly.

new style pump(with screws incover) fails, but drops bearings into motor.

Please help me understand the benefit of new style (amplify).

Thanks