This is true.
Cars, especially newer ones, have tons of technology in them. Give your kid a screwdriver and a pair of pliers and turn him lose in your garage. He’ll learn so much taking your new Toyota down to the frame and seeing how many parts he has left over when he reassembles it.
…Gasoline is corrosive and carcinogenic (and will carry poisons through the skin). Used oil is carcinogenic and hazardous if ingested. Engines and engine parts are crush hazards. The steel contains cadmium and other dangerous elements. Filters and gaskets contain dangerous fibres, and the exhaust systems contains dangerous dusts and heavy metals. A car battery is explosive, a burn hazard, a crush hazard, and is full of lead and acid. And there are electrical components too…
Sounds perfect for Mainway Toys.
Scare much?
How about a cite that gasoline is corrosive or will carry poisons through the skin?
The steel is an alloy so any cadmium is encased. Filters contain no dangerous fibers. Old gaskets might contain asbestos, but most of those a were phased out in the 1980-90s.
Since the elimination of lead in fuel no heavy metals in the exhaust, and what dangerous dust are you referring to?
You are correct that a car battery is heavy and does have lead and acid in it. Congratulations you got one right.
I’m not asserting that old cars are dangerous. I’m merely agreeing that they are more dangerous than old electronics.
You really should read your own cites before you post them.
From the MSDS in your first link
Funny I don’t see a damn thing about varying poisons through the skin. Or anything about it being corrosive.
Gasoline is a mixture of things like Octane and Heptane. Gasoline is a mixture of solvents. Solvents dissolve solutes. Solvents carry dissolved solutes through membranes. That is what solvents do. That is what solvents are. That is what Gasoline is.
Octane and Heptane are intoxicants. If swallowed or inhaled, they will cause intoxication (which may be fatal). Octane and Heptane are solvents. If swallowed or inhaled they will dissolve surface coatings (which will be fatal).
English has many words. Many more words than other languages. But even in English there is not a separate word for every concept, nor a separate concept for every word.
If you are a child and you get gasoline on your skin, and leave it there, you will get a chemical burn. Colloquially this is called “corrosive”, because it causes corrosion of the skin. If you search for “corrosive”, you will find that gasoline does not corrode iron/steel. This is a valuable property of gasoline, but it is not the only meaning of the term “corrosive”. (If you are not a child, you will have thicker epidermis, and you will get chemical damage to the skin, but the epidermis will protect you from more of the direct effect).
Gasoline is, of course, only one of the hazards of rebuilding cars. From bls.gov I see
Incidence rates1 of nonfatal occupational injuries and illnesses
Automotive repair and maintenance: 3.0
Electronic […] repair and maintenance: 1.4
Of course if you talk about fatalities instead of injuries, Auto-mechanic and radio-repair aren’t even on the same page
Occupations with largest number of fatalities,
You know what else is a solvent? Water.
Just because you see a word, in this case “solvent” (or “intoxicant”), you don’t have to assume the worst. Rick has been a mechanic since I was young (which I’m not anymore) and he hasn’t dissolved or been turned into a drooling idiot from contact with the dread solvents and intoxicants.
I swear, everything is so alarmist anymore. Everybody is so frightened. Get your hands dirty. Take things apart. Learn how they work. Don’t be so afraid of things.
For a day of fun, give your kids a crowbar, a hammer and a wrench, and set them free in a junk yard for the day. What could possibly go wrong?
That sounds like an adventure playground which turn out to be just as safe as a regular playground.
I have a 10-year old who also loves taking about electronics or electrical devices. He always asks first and I usually let him, unless there is a CRT involved or big capacitors. He’s not eating the stuff, and the occasional minor shock or cut is a good learning tool.
Recently he took apart an old laptop, cut up one of the plastic layers of the screen and inserted them into a pair of empty frames from some old 3D glasses which turned them into kaleidoscope glasses. He and his sister had fun trying to walk around the house in them. They had a great time.
Taking things apart isn’t nearly as dangerous as following the bad advice you can get from strangers on the internet! Better keep him away from that computer. 
+1! I did that as a cub scout project and loved it.
Another fun science project was Cartesian divers: put some paper matches in a glass pop bottle, fill it with water, top it with a scrap of balloon secured with a rubber band. Press on the balloon to put pressure on the water, which compresses air bubbles on the match heads and they sink. Release and they rise. You can see the bubbles change size and its a great intuitive lesson in relative density.
We should probably have a thread for good kids’ science projects.
I remember stretching pieces of balloon over soup cans with some water inside and heating them on a stove burner. The steam expansion was cool and could be controlled to a degree my moving the can or lifting it off the burner.