Destroyed the Engine in my Daughter's 300D - PeachParts Mercedes-Benz Forum

#1 03-01-2003, 12:31 PM

Well, I'm embarrassed to tell this, but maybe it will help others to keep from doing the same thing.

I started the engine on my daughters 300D this morning. I had just put a used IP on it and charged the battery over night. I bled a few lines and it wasn't too hard to get started.

When it started, it went to maximum RPM. I turned off the key, but it didn't shut down. I pulled the linkage all the way to stop, but it kept going wide open. I knocked the link from the upper linkage to the pump loose from the upper linkage and pulled the link as far as it would go, still nothing.

I then pulled off the intake hose from the air cleaner and put my hand over the intake. It took the RPM down to about a third of max, but refused to shut down. It was getting VERY hot, so I abandoned it and called the volunteer fire department to get them rolling in case it blew and started a diesel fuel fire inside my shop building.

From the time it started until it finally siezed was about four or five minutes I would guess. In that mental state, it's hard to estimate time. I never looked at a watch or clock. It took about another five minutes for the steam to stop blowing from the radiator.

The engine that came out so good after the rebuild is now scrap iron. I will now have to decide whether to use it for parts, sell parts from it, or just sell it for a parts car to someone.

This is all very sickening. The car wasn't really worth putting a rebuilt IP on, but hindsight is always 20/20. I would at least have something that runs had I done that. I gave $150 for the IP.

The next time I do something like this, I will remove the air cleaner before I start it up. That way I can seal off the intake completely if something like this happens.

I guess things happen.

Have a great weekend,

engatwork · #2 03-01-2003, 12:37 PM

durn - hate to hear that for you Larry.

84300DT · #3 03-01-2003, 12:37 PM

i feel your pain - sorry to hear about it.

psfred · #4 03-01-2003, 12:38 PM

Larry:

Very sorry to hear that. Terrible experience!

The shutoff wasn't connected to the internal linkage, and the governor fell to wide open.

For what it's worth, the ONLY way to get one to stop under these conditions is to open the injector lines. Makes a mess, but that is better than a thrown rod or seized engine.

I ALWAYS keep an appropriate sized wrench handy (as in my hand) when starting up after doing any IP work. Never had to use it yet, but there is always a first time. You have 30 sec or so to get the first line off -- disconnecting the fuel won't work, there is enough in the pump to throw a rod. Plugging the intake only works if you can completely seal it off.

ALWAYS, ALWAYS verify that the shutoff works (as in pulls the stop lever down) before starting an MB deisel after doing any IP work. On the vac governors, keep that wrench handy, no way to check!

Peter

diesel don · #5 03-01-2003, 12:39 PM

Larry,

That is terrible. I still don't understand why it went to wide open. I've re-read this a couple of times and still don't get it. Seems like you did everything well.
Makes me feel rotten for you.

Don

#6 03-01-2003, 12:49 PM

psfred,

I'm pretty sure I understand what you're saying. If I had put my handheld vacuum pump on the shut off, I should have seen the linkage move. This verifies shut off operation.

I did think about loosening the injector lines, but I was afraid it would be dangerous to have fuel spraying all over.

Thanks for the critique. Life is about learning. Some lessons are cheap and easy, and others aren't.

Have a great day,

leathermang · #7 03-01-2003, 01:18 PM

That really is sickening. And can happen to anyone easily... TCane was setting the ip on my 240 and told me to start the engine... it went way up in rpm and I shut it off with the key... it did shut off...

I do think your story indicates that you need a CO2 extingusher in your shop building... they are clean, unlike other types, and reusable until they are empty.... I too rely on volunteer fire depts and it sure can take a while for them to get to your location....

I too am a little fuzzy on exactly what happened and how to avoid it for sure in the future... in case anyone is willing to start at a more basic level describing what happened.... Thanks....

psfred · #8 03-01-2003, 01:38 PM

Larry:

It's messy -- Hans told me his father got a new suit once from MB for doing this. He was driving a brand new 190 (sometime in the late 50s, I think), and when they came down off the Autobahn, the engine was stuck at full throttle and wouldn't shut off. Since they owned a taxi company, he knew what to do and had the tools with him, but got well splattered with diesel fuel while loosening the cap nuts.

The problem turned out to be a failure in the IP, and I guess MB thought a new suit was much cheaper than a new engine!

Sometimes you can kill them with the clutch in high gear with a manual, but with an auto you will still probably just blow the engine (and tranny, for that matter) by putting it in gear.

Sad.

Peter

#9 03-01-2003, 02:18 PM

Yes, that's another score against automatic transmissions. Everyone here probably knows by now how much I like my sticks. Had it been a stick, I think I could've killed it pretty easy.

Thanks for all the responses,

Bill DeWitt · #10 03-01-2003, 02:22 PM

Larry, as indicated with all the posts, we all feel
your pain. Bill

#11 03-01-2003, 02:25 PM

Man that sucks. At least we all learn something from the misfortunes of others here. Now I know that if I ever have to do anything to my IP pump that I need to be ready in case of a runaway diesel.
As far as my stupid mistake of the week which could have cost me big time I dropped a 13mm socket that ended up on top of my harmonic balancer. My magnet could not reach it so I said to myself "I will get it with a coat hanger when I get back from the parts house" Guess who forgot about the socket until I turned the engine over and locked it up.

Palangi · #12 03-01-2003, 02:28 PM

Sorry to hear about your misfortune Larry. Hell of a way to start the weekend.

mechmagcn · #13 03-01-2003, 02:35 PM

After having several Detroit engines '' run away" I know how it feels. Most of them have emergency shut down systems which shut off air intake. I have knocked the fuel filter off of one with a hammer

. A customer last year had a Mack engine run away, and then called me. When I pulled up the driver started it. Couldn't get a hammer fast enough, it threw # 6 rod, knocking the starter completely off

. We were dodging flying pieces!
Again, sorry to hear this, Jeff
If you decide to sell the car, let me know.

joshhol · #14 03-01-2003, 02:38 PM

My condolances. Seems like your taking it really well.

#15 03-01-2003, 02:45 PM

josh,

It may seem like I'm taking it well, but you're not here to see me. Things have been going pretty bad for me for quite some time. The company I work for is almost broke and I've had two pay cuts in the last two years.

mechnagcn,

I just put a post in the parts section notifying that I am parting it out. If you are interested in the whole car, contact me soon. I will be checking my email Monday morning. I'm sure I won't pull any parts before then.

Thanks everyone,