seized engine on my SDL ? - PeachParts Mercedes-Benz Forum

surfblau · #1 06-10-2003, 11:02 AM

I am not happy this morning.

Over the past 3 days, my SDL been making a louder and louder clanking noise from the front of the engine. I usually pay really close attention, but I ignored it the first day (it was really minor, and only noticeable at idle). The past two days, the noise had gotten louder, and I initially thought that it was something with the serpentine belt, but pushing the shock/tensioner/pulley did nothing when I checked last night when the engine was hot.

When I was checking the belt, it seemed like the clanking was coming from the front of the engine. Just for good measure, I added some oil before some more observation prior to my morning commute.

I started the car, it ran for 20 seconds, clanking right away, then missing or studdering once and then died (while I was watching it from the front bumper). It kicked slightly more than normal when it shut down and maybe made a bit of a click. I attempted to restart, but I can't tell if it is turning over- though it sounds very strange when cranking and will not fire. I didn't try hard to restart, clearly it wasn't going to work.

Does anyone have some specific recommendations for what to do next?

I have never checked the chain on this car, but I guess I will tonight. Based on other threads, it sounds like the chain and tensioner are suspect, which sounds like it has grave implications for the engine as a whole. Anything else that I should check first? Can anyone recommend a troubleshooting proceedure for the 90 minutes that I will have to work on the car this evening?

Fortunately, it is resting in my paved carport under a nice big oak tree.

Crossing my fingers that the engine in not toast...

(some other facts, the car has a new head and radiator - not put in by me, I put in the new vac pump, oil pressure was allways at 3 when in drive).

alec

rickg · #2 06-10-2003, 11:11 AM

Eewww! Sorry to hear about his Alec. Hope it isn't TOO serious!

surfblau · #3 06-10-2003, 12:29 PM

Six cylinder, OM603. When it died, it was idling slow, so I am cautiously optomistic....

rickg · #4 06-10-2003, 12:33 PM

Sorry to get off topic here for a bit, but I have to chuckle everytime I see Virginia Dudes past car list. The '73 Honet wagon. I had a '73 Hornet some 20 years ago. Was a real mixed bag, some of it was a great car, some of it was a real POS!

Ok. Back to the program.

JimSmith · #5 06-10-2003, 02:01 PM

Surfblau,

From your description it seems the problem will not be trivial. You might consider removing the valve cover and doing a good visual inspection of the top end working parts to see if you have any broken parts in the valve train, including the chain. If that looks ok, you might try turning it over in the normal operating direction by hand. If it turns look, listen and feel for any abnormal aspects, like scraping, or being frozen, or being too easy to turn. Observe the valve train response also.

Unfortunately your description sounds ominous. Let us know what you find when you get the valve cover off. Good luck, Jim

#6 06-10-2003, 02:38 PM

Sorry to hear, sounds like you're in a bit of trouble. I wish you luck.

JPL · #7 06-10-2003, 03:00 PM

OUCH !
and i was gonna complain about getting a front quarter panel replaced and painted. Watch that Depford , NJ Sam's Club Parking Lot ! theres someone there that hits and runs. Had to be one of those 4x4s based on the impact.

I hope the engine isnt too much.

rickg · #8 06-10-2003, 03:18 PM

Quote:

Originally posted by TheVirginiaDude
Back to topic, I am no OM603 expert but isn't that the one with the suspect connecting rods? The ones apparently made of the same material Twizzlers are made from? Well maybe you will get lucky and it will be an easy fix, But I wouldn't hold my breath.

No that was the later 350SDL engine in the 90's. Worst I've heard of the 3liter 6cyl was warping & cracking cylinder head. But what he has sounds like something different.

surfblau · #9 06-10-2003, 03:22 PM

The 300SDL is known for cracked heads, which was replaced on mine a couple of years ago.

sixto · #10 06-10-2003, 05:08 PM

Alec, pull the vacuum pump to see if it's intact. With the 603.96x, unlike the 603.97x, my first suspicion would be that the vacuum pump spat out something that wound it's way down the timing chain.

If that's the case, thank goodness for the separate side chamber for the sump.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

P.E.Haiges · #11 06-10-2003, 07:57 PM

Sixto,

I saw that side pan in a parts book. Do you know why its made that way. Is it for more road clearance or what?

If the main oil pan is damaged from hitting something, it looks like the bottom steel pan can't be R&R like the 615 engines. Looks like the entire pan would have to R&R. Is that correct?

P E H

sixto · #12 06-10-2003, 08:22 PM

My guess is that they can configure the sump for a variety of capacities and/or there are some 603.96x applications that require installation of the side chamber after the engine is installed.

There is only one main section of pan in the 603.96x and it's an aluminum piece. Not like the 617 that has an aluminum skirt and an iron sump.

The 603.97x supposedly doesn't have the removeable side chamber.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD

tjohn · #13 06-10-2003, 10:41 PM

Just to be absolutely clear, since it sounded like there might be some confusion earlier in the thread, the OM603.961 is a 3 liter 6 cylinder engine that , at least in the U.S., was found in the 86-87 300SDLs and the 1987 300D. The OM603.970 is a 3.5 liter 6 cylinder engine that in the U.S. was found in the 1990-1995 300SD/S300. The former - Surf's version - was prone to cracked heads, the latter was the rod bender.

Surf - I wish you luck, please keep us posted.

gsxr · #14 06-11-2003, 05:49 PM

To pick nits:

603.960 - 3.0L, 1987 300D/TD
603.961 - 3.0L, 1986/87 300SDL

603.970 - 3.5L, 1990-91 350SDL (all W126 diesel)
603.971 - 3.5L, 1992-95 300SD, S350 (all W140 diesels)

tjohn · #15 06-12-2003, 12:55 AM

You nit-picker you...

Thanks for the clarification; the point I wanted to make clear is that there are "good" 603s and "bad" ones so people don't get confused.

Surf, Surf, how goes it???