I'm sure that there are countless threads like this that have been posted previously, but I just had a "Am I really this stupid" moment that I had to share, and I'm hoping to hear some other stories to help me cope.

I've been working on my instrument cluster the past couple of days and my car was due for an oil change. I get home, park the car and drain the oil pan. I usually let the pan drain for about 15 minutes before screwing the drain plug back in. While the oil is draining I figure that I might as well replace that bad bulb in the instrument cluster. My steering wheel was about 35* off center, so I'm like, okay let's just turn the engine over and turn the wheel to center. It took me 3 seconds to realize that THERE'S NO OIL IN THE ENGINE!

I'm praying that I didn't just take about 50K miles worth of life off of this incredible 617 that I dropped into my 300SD two years ago.

__________________
'81 300SD

3 seconds? That's no big deal. You might have taken off 50 miles or something, but I wouldn't sweat it.

I'd be hard-pressed to say the dumbest thing I ever did. There's lots of them, and for a few of them I wouldn't be here, but for the Grace of God.

One habit I got into at one point many years back (if I had done something that would keep me from trying to start the car until I was sure I wanted to) was to put the key inside the house in a drawer or something. More than once that has proved useful as I'd think "Oh I want to do this" or something and then grab for the key, only to go "wait, where's the key" and then "Hey, stupid, you want to reconnect the fuel line first!"

At any rate, good luck, and seriously, stand down. That's not going to have any consequences.

Let's see...

Started an oil change but realized that I didn't have a good way to get the oil filter off. I drove back to my house in another car to get lunch, had to run some errands, went and got what seemed to be the correct size wrench. So about 5 hours after starting the change I come back, try to use the oil filter wrench, it slips off so I just go get a screwdriver and a hammer to remove it. Got it removed then started pouring oil in then realized at 4.5 quarts in that I forgot to put the drain plug back in. That was a mess.

I also late one night finished on a car and took it out for a test drive cause the next morning I was going to pick up a girl for a day long date. Got out on the highway and noticed a terrible shake. I quickly realized that I had only hand tightened the lug bolts so I dropped down to 40 and put my hazards on and got off at the next exit, pulled into a well lit parking lot and used the tool kit to tighten them down. A few of them had worked their way out 3-4 turns.

I also once was doing a coolant flush. Idrained the block and the radiator, and ran tap water through. I put in a new thermostat, then hooked everything back up and poured in coolant into the expansion tank. We then started it up to purge the system and the temp quickly shot up to 120. At that point we realized that we were supposed to fill the engine before reattaching the upper radiator hose. That incident may have some to do with why the head gasket is seeping oil.

Yeah, I forgot to put the drain plug in during an oil change years ago. Seeing fresh oil near my foot kept me from starting the engine

__________________
'81 300SD

Otto I seriously doubt you did any damage at all. I'bet with no load it would be
minutes before damage occurred.

My stupid mistake HURT. I built a 400SBC powered Jaguar XJ12. I was in my
Dads garage setting up the jetting. At one point I put it in gear to see if the idle
was OK. I forgot. I was leaning over the engine bay and blipped the throttle
the car jumped right onto my foot and right against the garage wall I could not
go further forward. I hurt so bad I started yelling. MY Dad ran out and couldn't
figure out what to do. I yelled at him to put it in reverse, he did so but got freaked that it moved a foot and put it in drive and ran over just the tip of my foot again, saw what he had done and corrected. Cripes he felt SO bad. I couldn't
walk right for a couple weeks but nothing broken.

__________________
85 300TD FED-Daily
84 300SD-Wife's
86 XJS-Sunday
66 GMC-Work- Given to my stepson
83 BMW Airhead- Given to my stepson

@Otto
If it makes you feel any better, I fired the Om617 up after I had disconnected/replaced the oil cooler line and she was way (too) low on oil, since quite a lot had come out of the oil filter housing etc. Anyway, I start the engine, realize there's barely any oil pressure (the gauge starting climbing very slow), I turn the key to turn her off and realize we had knocked of a vacuum line, so she kept running. I was a little panicky as I I run out of the car to open the hood and shut her off. She probably ran for 15-20 seconds with too low oil pressure.

She's fine.

My problem is that I suck at mechanics and have two left hands, but I keep working on my cars, and thereby make stupid mistake after stupid mistake. Here, to help you cope better are two stories:

Not on a Mercedes, but back when I lived in The Netherlands I had this tiny little French hatch-back. A Citroen AX. Me and my brother were changing out the front wheel bearing, since I'd had a stuck brake caliper a week or so prior, and it had cooked the bearing when the hub assembly got super hot.
Because we didn't have a press we removed the whole strut, so we could drop it off at a shop to have the new bearing pressed in.
Anyway, got the new bearing in, went to mount everything back and put the car back on its wheels and went to take a little break before the test drive. A cup of coffee later we walk back outside, and realize the whole front wheel had moved several inches forward and was actually starting to hit the fender and pushing it out.

Reason? Forgot to put the bolt in that holds the ball joint that connects the wish bone to the hub assembly. So basically the lower part of the strut was not attached to anything, and so everything could move freely about. Oh boy, if we hadn't taken a little break but would've jumped right into the car and backed out of the drive way, we'd have a lot of damage to deal with. Felt SO STUPID. Luckily nothing important got damaged.

Also on the same car a year later.... I was helping my best buddy move to his new place, and had parked my little French car in front of somebody's garage. The wheels were turned, and as I get in the car to drive away late at night the key breaks off in the ignition. Should've seen that coming, the lock had been sticking for months, but alas: It was low on the priority list. Anyway, buddy drives me home to get a new key, but the lock is now completely broken and won't turn at all. It seems W123's suffer from the EXACT same thing, but anyway: I now have a problem since I am blocking someones garage, and I can't push my car away since the steering isn't straight, so it's important to get at least the steering to unlock so I can move the car away and deal with the rest later.
So, with our sleepy heads (it was late) we grab a metal drift punch and a big-ass hammer and I start pounding that drift punch into the ignition lock to attempt to break all of it. I had a spare ignition tumbler, so I couldn't care less about breaking out the old one.
But.... I forgot to disconnect the battery. And so the moment the metal drift goes through the ignition there is smoke everywhere and the wiring harness behind the dashboard catches on fire. Literally, fire. The battery is cooking, smoke everywhere while the engine wiring harness is also going up in smoke. It was terrible. I got a little bout of super human strength as I run out of my car in a panic (crying, actually, kid you not, because that old hatch-back was my one and only car and daily driver) and I rip open the hood (without having popped it first) and yank off the negative battery lead. Burned my fingers in the process.

Long story short: it took a month, a month(!) to get her back on the road. We had to re-solder pretty much the whole wiring harness, which thank God is pretty small on an old '80's hatch back and had to remove the whole dashboard. The only original wiring left is what ran to the rear lights, everything else had to be replaced. I had never soldered once before in my life, so it was a good experience I guess.

The first time that engine fired up again and everything worked and had proper electric power felt like one of my biggest mechanical accomplishments ever... . Everything worked, except for the rear window wiper which never worked again after that.

Anyway, that must have been the STUPIDEST mistake I ever made. Had I just disconnected the battery, I would have been done with changing the ignition.

To this day I disconnect the battery to my car every single time I need a wrench for anything. Call it overkill, but I NEVER EVER want to risk setting my car on fire ever again...I still have nightmares, and I still have the pictures of when we worked on the car and took the dash out to remind me to always disconnect a battery...

@NoSparkNeeded
Yikes! That must have been terrifying...

__________________
"The MB W123 is so bulletproof, you can drive them forever. Which is a good thing as it takes that long to get anywhere."
Betsie: 1984 W123 300D (hobby, 280k miles)
Myrla: 2001 Mazda Protege 2.0 ES 5spd (daily driver, 130k miles)
The Turd: 2007 Toyota Camry (wife's car, 118k miles)

Three:

Nearly lost a pinky trying to torque down the massive bolt on the VW flywheel, was holding the FW with a large screw driver, things slipped and my pinky got caught between the housing and starter ring. Not even really clear how it happened, I would have been 18ish.

When I got my current DD, I did an oil change and took it off the ramps and left it there. I got the oil and was walking away from the car, carrying it to dump back into the containers, when I heard a twig snap. Turned around just in time to see the car rolling in my direction and managed to back up a few feet before it rolled into my benz motorohome. Put a dent in the front quarter that is still there, mostly to remind me about safety. This happened within the first hour of ownership of that car.

Taking head off 603, had the sprocket off the cam and needed to turn it a wee bit. Decided the centering ping on the cam to sprocket surface would be a great place to stick the screw driver to get some leverage. That cam sits on the wall in the garage right in front of the car to remind me about thinking things through.

__________________
http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

To the OP, I've done the oil fill with no drain plug too. It was the first and last time i've done it, now I always double check

I've only had my w123 for about a year, the only thing I've done so far (because of many thanks to this forum) is while wrapping up changing my heater hoses, I leaned over the passenger side of the radiator to admire my work and promptly set my elbow on the overflow nipple, snapping it clean off..

Got the steel tire valve stem in as a temp fix

__________________
'82 300TD
'84 300D OM617
Auto to 4spd Manual Swap 716.210
'85 300SD 2.88 Diff (Direct Swap)
W140 HD Rear Springs w/ bilstein shocks (SLS Delete)
'83 300SD Big Brake Booster Swap
Late model 240D Manual HVAC Swap
W124 Outside Temp Gauge
Aftermarket Keyless Entry

'84 300D RIP

In the 80s I worked on cars for spending money when i was a teenager. I did thing like changing trannys, alternators, brakes, etc. mostly GMs, cutlasses and the like. My own car was a 79 Cutlass with a stone chip in the windsheild.

Once I was doing a tranny on a 78 cutlass. tons of rust underneath and I kept getting it in my eye, well i got pissed and i chucked a socket at the ground, and it bounced off something and hit his windsheild.

Well, i had finally found a windsheild at the junkyard for my car, one that was tinted, that had the radio antenna built into the windsheild that some cars had back then. Well, it ended up having to go in the customers car. I never found one like that and i dealt with the chip for all the years I had the car.

a month after I see the guy with the 78, and he mentions that he had the car 4 years and he cant figure out how his windsheild suddenly became tinted.

__________________
1959 Gravely LI, 1963 Gravely L8, 1973 Gravely C12
1982 380SL
1978 450 SEL 6.9 euro restoration at 63% and climbing
1987 300 D
2005 CDI European Delivery
2006 CDI Handed down to daughter
2007 GL CDI. Wifes

I had an old w115 240D. I was working on some item that I can't remember now but decided that it was necessary to crank the engine. Instead of getting in the car to do so I decided to just "arch" the starter. Well, the car was not in park or neutral. It was in drive. Thankfully I had a large back yard. It took me a little while to chase it down.

I have done all of these and more... Working on cars since I was 5 years old... Literally... Fondly remember working on VW beetles and things in the early 70's in ... Iceland...

Try setting the dwell and checking the spark output while leaning on the fender of a 57 thunderbird... I think my ears are still ringing from the yelling...

__________________
John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Now that's funny!

Two boners:

1) Didn't read the FSM when removing and replacing the chain tensioner. Just took it out and put it back without re-setting the plunger. Burnt the banana rail down to the metal before I figured out what was wrong.

2) Grabbed a jug of oil and began pouring it in the valve cover. About 1/2 quart later, I noticed it seemed a bit thick. Turns out it was 80/90wt gear oil. The jugs were identical with same color label, but still pretty stupid.

I have learned the hard way to take my time as I get older.

__________________
1981 300TD 310k miles
1970 280sel 172k miles
1966 230 Fintail 162k miles

"Where are we going? And why am I in this hand basket?"

I used to live in a townhouse where I wasnt supposed to be working on cars... so Im doing an on the DL brake job on my 300e with the garage door closed (the door to my practically non existent yard was open). About a half can of brake cleaner later Im high as a kite and torque down the calipers bolts... at least they seemed tight in my altered state... go to drive the car around the block to test and hear a clunk.. thwack, thwack, thwack, thwack... luckily the car stops. I look and one bolt is about half a block back on the road and the caliper is hitting the inside of the wheel only held on by one of the two bolts. Moral of the story.. don't huff brake cleaner.

__________________
1990 300e 230k (old reliable) sold
1987 300D 230K sold
1987 300D 232K 5 speed
1998 E300 140K

I cut the cruise control cable in my 240D. It didn't work anyway but it was pretty dumb to cut it.