Turbo Failure/wear Verification - PeachParts Mercedes-Benz Forum

Ralph Burnette · #1 08-20-2003, 08:59 PM

I have a 1993 300SD with 214,000 miles on it.

I have a lack of power. I recently traveled to West Virginia
from Connecticut and the car could not hold road speed going
through the mountains (interstate).

I noticed a little some oil leakage at the crossover at the intake
manifold. There also appears to be some oil coming from the
turbo side of the crossover (although it is hard to tell).

Is there anyway I can inspect the turbo to determine whether
or not it is worn? Are there other things to check, too?
Are there any DIY procedures I can use?

Thanks,
-Ralph

R Leo · #2 08-21-2003, 07:22 AM

Try a search of the Diesel Discussion using these words:
'turbo check', 'turbo function', turbo operation'...lots in here about that stuff.

tjohn · #3 08-21-2003, 08:08 AM

When I hear your symptoms, the first thing that comes to mind is that you got a bad batch of fuel. I assume you've already swapped out the filters/checked for algae? Is there a particular reason you suspect the turbo?

Ralph Burnette · #4 08-21-2003, 11:24 AM

Power seems inconsistent. On long grades where I am running
at 70MPH or so, the car slows down to 60. I have to force a
downshift to keep roadspeed up to a reasonable level.

In addition on a short upgrade (starting from stop), I seem to
have no power; no real pull.

In addition, there was some oil seepage at the crossover and
the intake manifold, indicating some blowby or that the turbo
seals were leaking. It is possible that my mechanic ovefilled the
oil a little during the oil change just before I left for the trip.

I checked the turbo. There is virtually no play in the shaft and
it spins freely without any catching, etc. so I am not sure that
it is the turbo anymore.

When I was looking at the turbo, I noticed that the vacuum
line to the EGR valve wasn't down all the way on a connector
to another hose. In any case, it is fairly easy to slide in and
out.

I am looking for a pump to do some vacuum tests which is next
in the plan.

On the opposite side of the engine near the firewall there is
a sensor where a number of vacuum lines connect, including
one coming off the intake manifold. Does anyone know how
to test it?

Thanks,
-Ralph

R Leo · #5 08-21-2003, 04:21 PM

Yep, if the onset of this problem was reasonably fast it's probably fuel. Change the filters and run some Power Service or other diesel additive through.

kashbaugh · #6 08-31-2003, 11:22 PM

At the risk of asking a stupid question, what if the symptoms did not "appear suddenly"? The reason I ask is that sounds like the performance of the 300TD I just bought. I thought it was just "normal" diesel operation. No?

kma

psfred · #7 09-01-2003, 05:00 PM

Check the white plastic line from the center of the manifold (92 350 SD, 603 engine) or the rear of the intake manifold (617 engine) for leaks. The rubber bits that connect the plastic line are old and hard by now, plan on replacing all of them in the engine compartment.

Also check by blowing down the line that it holds pressure. If not, check the switchover valve on the firewall for leaks. It goes (on the 603) from manifold to switchover to ALDA (aluminum squarish box on the injection pump) to the blue vac amplifier on the driver's side fender for the tranny.

I'd bet you have a fault in the pressure sensing lines, so you don't have pressure on the ALDA and no extra fuel. That 603 shouldn't have any trouble at all holding any highway speed you want at any altitude!

Peter

Ken300D · #8 09-02-2003, 06:55 AM

93 300SD = Bent Connecting Rods.

Ken300D

tjohn · #9 09-02-2003, 07:18 AM

Quote:

Originally posted by Ken300D
93 300SD = Bent Connecting Rods.

True enough, but thankfully Ralph doesn't report those symptoms, and since he's at 214K maybe he got a good one?

Ralph - did you check along the lines Peter suggested yet?

Ken300D · #10 09-02-2003, 11:43 AM

I thought perhaps the connecting rods could bend at any time during the life of the car - depending on when it finally ingested EGR-induced chunks of carbon.

And then I thought further that bent connecting rods might result in reduced performance.

Maybe the symptoms are more quickly obvious when you have bent connecting rods.

Ken300D

#11 09-02-2003, 06:06 PM

If bent rods were the result of ingesting intake manifold carbon/sludge then 603.96 and 602.96 engines would suffer from it as well (as they carbon up JUST like the 603.97 engines) and the rebuilt 603.97 engines would be doing it by now! That's not happening. The original OM603.97 engine design was the problem. With new rods, they seem to work just fine. OM603.97 engines almost never present with low power. High oil consuption/smoke or broken rods are the usual peresenting symptoms. Most low power conditions are because there is either insufficient boost activating the ALDA (and fuel enrichment) the ALDA aneroid is broken or the overboost circuit has been activated.

Marshall

DslBnz · #12 09-02-2003, 09:07 PM

Quote:

Originally posted by Marshall Booth
If bent rods were the result of ingesting intake manifold carbon/sludge then 603.96 and 602.96 engines would suffer from it as well (as they carbon up JUST like the 603.97 engines) and the rebuilt 603.97 engines would be doing it by now! That's not happening.

Check my posts and follow my progress. Maybe I'll be the first one to have one of the new engines blow up.

Go to 350SD, burning oil SECOND STAGE ENGINE

tjohn · #13 09-02-2003, 09:41 PM

Dr. Booth - great to see you here, hope you stay awhile. Ladies and Gents, as a lurker on the MBZ.org diesel email list, let me say that we're in for a treat if Marshall is going to hang around and share his knowledge.

#14 09-02-2003, 10:01 PM

[QUOTE]Originally posted by DslBnz
[B]Check my posts and follow my progress. Maybe I'll be the first one to have one of the new engines blow up.

I'm sure it's NO consolation when your engine is drinking oil, but the failure rate for the rebuilt 603.97 engines is similar to other MB diesels (maybe 1% give or take) while the original engines had a failure rate MUCH higher than any MB engine I've ever heard of.

Marshall

DslBnz · #15 09-02-2003, 11:54 PM

Do you know of any 350's with those new engines with over 178K miles on them? That would mean you'd have to find a 350 with around 240 - 300K miles on them (how many are there, anyway?) I've seen original engined 350's go 220K miles before any rod-bending. It can happen at any time, apparently, and it evantually does. How many 350's out there in excess of 400K miles on the original engine? None I can document, yet.

I am not saying my engine has failed yet, but chances are, it will. I do not know of anybody in my area who even OWNS a 350 because they are so rare. How do you know they are lasting 3 - 400K miles, no prob(and beyond?)? The engines are just too new, and the cars are too rare. If you could tell me about somebody who actually has a 2nd 350 engine with that kind of miles, I would be extremely interested in looking at it, out of curiousity.

I've seen several 300's (OM603)with over 400K miles, and some had close to 500K miles. Still running, with the third generation heads, of course! My 300SDL doesn't burn a drop of oil!

Sorry if I sound rude; I'm upset, and am looking for a logical solution to a very challenging enigma.