Question of the Week: What’s the dumbest mistake you’ve made working on your car?


Bought a1968 Fury green on green 4 door sedan with a 318 and a white old folks garage door frame racing stripe down the passenger side for $125. The owner said it just kept running worse and worse until it wouldn’t even start. Towed it home and proceeded to replace EVERY part in the ignition system including the starter due to 3 days of cranking on it and barely got it to fire. Went to the carb next with still no luck. After 4 days my dad comes over, pops the cap off the distributor and puts a socket on a breaker bar on the crankshaft and rocks it back and forth about 3 inches and the distributor never moved…after all that work it turned out to be a shot to hell timing chain and gears…ran like a charm after that and dad has never let me forget that one!


Been there, fortunately didn’t loose all the oil but enough to create a mess in the drive.
Always check now before I put the new filter on.


There have been a few, forgetting to tighten lug nuts, not putting the oil filler cap back on, not disconnecting the battery before working on electrical… but the worst would be after freshening up he 455 in my Buick GS. My first major engine teardown and it went back together well. Unfortunately I didn’t prime the oil pump before trying to start it. Only ran less than a minute before I noticed no oil pressure but the damage was done. Lesson learned and the next engine I tore down and put back together ran well for years.
If only I had a ‘do over’ on the first one.


Mistake was a Major one was replaceing motor in my 70 chevelle as I need the car for the weekend .I was working on it late into the evening out side in yard . I had driven the car onto ramps to get to all the bolts needed to remove engine headers wireing and transmission had everything ready to except to remove drive shaft you can guess where this is going being too tired and late in the evening I did everything right except for two things didnt set parking brake and didnt block wheels.The car rolled off the ramps backward with me on my belly pinned under car looking at wheel of car in panic mode ended up doing push ups to get out from underneath needless to say we never did this foolish act ever again . many cars and engines have been replaced since safely . Amen


Trying to remove the battery, touched the wrench to my ring. Burned finger and $100 damage to the ring.


Well…I’d have to say the DUMBEST thing would be…yet to come…because I’m still alive to talk about it…
I know now that with my knowledge of how it should be done and my ability to get it done are never going to meet up soon…it starts out early with a few oil changes , move up to a few brake jobs and then you believe nothing is impossible…till you say…“UH OH” and you are swearing up a storm …again… I just recently retired and found out that its getting to difficult working on somethings to the point of breaking it just to have it towed in to get repaired what I intended to fix…I’ve had a few bone head mistakes in my years of working on cars, my only regret is that I haven’t gotten to that point yet where I sell everything I owe to prevent we from ever working on any car ever again…My garage was a place for filling the need to get some sort if joy out of that DYI everyone brags about but lately I just say…I’m dropping the car off hun…can you pick me up in a few minutes at Espo’s…I can’t even get my spirits up even for to wash my cars…I’m sure I can handle a light bulb or change an air filter or check the air in a tire without any backlash but as for wanting to rip into something because I felt a little vibration or I heard a squeak coming from somewhere…Never mind…" if it aint broke don’t fix I t" makes a lot of sense to me now…


I was rebuilding my engine for third gen firebird. Was installing engine back to the engine bay. It was pain in the ass to lineup transmission pins and engine mounts in the same time with engine. After two hour with taking out transmission i got it done. When it was time to bolt flexplate to the TQ i found out that i forgot to install flexplate.


In a short period of time at year end 1989, I made three dumb moves. I was an apprentice in a tire and mechanical service shop. It was November. A car came in at noon, he needed winter tires put on. No problem, except he didn’t have the key for the lock nut on each of the back wheels. The car was a late model Mustang, i used an air chisel to turn the locking nut, as i had seen the alignment guy do. Not thinking he always wore glasses while i didn’t. On the last locking nut, the chisel broke. The broke piece hit me in the eye. I wiped the blood away. Told my boss what happened. Finished the job. Then went to see the doctor.
I was the off for a while as my eye healed. During these weeks off i was trying to get a 1964 valiant read for my son’s birthday day on December 11. I has disassembled the car to paint it. We had no garage so I brought everything into the basement. I spred out the pieces and painted them. I forgot the furnace was circulating air through the house so for a week the house smelled like a body shop, yes that was pretty dumb just ask my wife. But since i was on a roll, why stop now. The weather was mild so i put the Valiant back together. Then i was going to do the rear brakes. It was warm enough the snow was melting. I had loosened the wheel nuts and had a small bottle jack to lift the car. I placed the jack onto the snow, and up to the frame just in front of the spring. I jacked the car up enough to remove the tire. With my right hand on the top of the tire and left near the bottom i began to wiggle the tire out from under the car. BUT then the melting snow let the car roll back and fall off the jack. But my right hand was wedged in between the tire and the lip of the quarter panel. Since i was by myself I had to reach across to the jack with my left hand, lower the jack, try to get it stable on the snow, then jack the car up enough to get my hand out. All this took a while. Turned out i lost my eye and 2 and a half fingers. I forgot about safety. I should have had safety glasses on while using the the chisel. I should have had blocks under the car to ensure is couldn’t roll. And i should have cleaned away the snow so the jack could sit flat. Since then i have learned to work safely, but i should have started sooner


When I was 18 (64 now) I replaced the differential of a VW Beetle. All went well and put the gearbox back in. It was from a friend of mine. He came to pick the Beetle up. Engine started and noticed the Beetle was transformed to have 4 gears backwards and only one forward.Foolish? Yes. But with this knowledge we created some buggies afterwards with the VW engines mounted with the engine forwards and gearbox backwards with great succes. Learn from your mistakes!


Man, been there with my Vair too! I’ve also had where I evidently didn’t use enough sealant. Bye bye 6-puck Kevlar clutch!


I remember way back when I was kid I wanted to make sure I’d put the drum brakes back together correctly after changing shoes…so I pushed the brake pedal without the drums on. It wasn’t pretty. I think one of the springs is still circling the earth.

Had a transmission rebuilt and pulled off the external switches and sensors before taking it to the shop. But I didn’t mark their respective locations. Two were almost identical with the same connectors. Re-installed the transmission and DOH!!!..they were wrong. Had to pull the transmission a second time just to access the switches which took about 2 minutes to swap.


I did this a number of times and finally Lou and Jared on CAR FIX mentioned it and straightened me out. Putting together a small block chevy, I always lined up the cam gear and crank gear so the dots were together instead of putting them at 12 o’clock. I could never understand why I was always 180 degrees out when I went to start for the first time. Where were you 35 years ago Jared!!!


On a scale of 1 to 10 this bonehead move rates probably a 9.5 or a 10. My brother-in-law was visiting and wanted to take a ride in my 1950 Ford Custom Fordor. So I charged the battery all night for a drive the next day. The bonehead move was I charged the battery backwards (I put the charger positive clamp on the negative post and the negative clamp on the positive post). Not realizing my mistake, the next day the car started and ran fine. While Mark was driving I noticed the amp gauge was pegged at full discharge. I thought ‘what could be wrong’ then realized my mistake. Terror filled me with all the electrical things that I probably fried. We got home without incident. However, when starting the Ford again to put it back in the barn I found that the starter solenoid was fried and the battery was dead. I attempted to charge the battery again (the right way this time) but the battery would not have it. It was DOA.
Old Fords are 6V positive ground system, but still no excuse, that was a bonehead move.


Replaced 2 broken flex plates on a '98 Rodeo before I realized the tranny guide pins were missing.


@pardonme.luckyangel - Sobering story of mistakes that really cost you. Thank you for sharing so we can all learn to correct some of our bad habits.


After removing the oil filter from my 04 F150 I didn’t realize the gasket from the old filter was still on the housing, I installed the new filter, added 7 quarts of oil, and as soon as I started the truck I realized there was a problem when the sound of squirting oil was apparent. Needless to say I had about 3 quarts of oil covering the engine bay and floor, it took quite a while to clean that up and I now had to make a trip to the store to buy more oil. Needless to say I now always double check the housing and the old filter to make sure the gasket is not stuck to the housing.


@kyinsagent - Watched a truck back out of my high school auto shop after a double gasketed filter change. There was a lot of floor dry used that day.


Yep! Same thing. Of the hundreds of oil changes and filling up of new engines with oil, you’d think that I’d always check to be sure that the old oil filter gasket was stuck to the block. Our (always talking) 86 Lebaron GTS 2.2 Turbo should have reminded me? Fortunately it was on the grass as I hadn’t gotten the concrete pad poured in front of the shop out back yet. I still had to dig out a nice sized chunk of dirt and to re-fill it with dirt from somewhere else though!


I was a young ( 18 year old) kid with a 1957 Thunderbird. I decided to install a hotter camshaft in my 312 Y-Block. So I removed the engine from the car because the flat tappets could not be pulled from the to to clear the cam lobes. I pulled off the crank pulley (not easy to do on a TBird), removed the timing cover, and turned the block upside-down on two heavy sawhorses because it was more stable that way.
Removed old camshaft and installed the new one, then carefully counted the chain links between the timing marks on the gear.
Put it all back together and it spit back like crazy. It took a while for me to realize the cam timing was way off because I counted the links between the crank gear and the cam gear while the engine was upside-down, thus I was WAY OFF. (The Shop Manual shows how to do this, but with the engine top - UP. Out came the engine again and I had to do it all over. Major waste of time, but a lesson I’ll not forget.


20 years ago had a 90 Tempo with a no start condition. Took me three hours to pull the starter, went and had the starter checked out…no problems. Then my dad comes out, “did you check the battery?” Of course, it was the battery.

Recently, I changed oil in one of my vehicles and the oil-transport-container was full so I put it in a cheap plastic oil pan (fortunately) until I could get rid of it. Problem was it sat for a few weeks and one day I went out to take the Galaxie for a drive and as I started to pull out of the garage I heard a strange noise. After the obligatory “What the…” I realized it was the oil pan that I had “stored” in front of the front tire of the Galaxie. What a mess and felt like and idiot.