5 Worst Cars for DIY Repair: Why Mechanics Hate the Pacer, 300ZX, and W12 VWs

Working on cars yourself is great. Until it's not.

Some cars, you pop the hood, swap whatever needs swapping, and you're back inside watching the game in 20 minutes. Others make you wonder why you didn't just pay someone else to deal with this.

Could be the engine bay's so tight you need to remove your ribcage to reach anything. Could be the car was designed for a totally different engine that never happened. Or maybe there's just so much random tech stuffed in there that changing the oil becomes an all-weekend project involving YouTube tutorials and profanity.

Every car's got at least one impossible bolt or filter placement that makes no sense. But these five get complained about more than most by people who've actually tried working on them. These aren't exotic supercars either—just normal cars that happen to hate their owners.

AMC Pacer

So the Pacer was supposed to get a rotary engine, like the ones in old Mazdas. AMC had a deal with GM to get one, but then GM just canceled their whole rotary thing. Pacer's sitting there, completely designed, no engine.

They grabbed an AMC straight-six and shoved it in. Good engine, really reliable. Except the whole car wasn't built for it, so the engine sits way up front practically kissing the windshield.

Last two spark plugs? Forget about it. They're buried under the windshield cowl where human hands weren't meant to go. People just leave old plugs in there forever because it's not worth the hassle. Some say the spark plug wires actually cook themselves under that cowl from trapped heat. Wild, considering that AMC straight-six is bulletproof—it's basically the grandparent of the legendary 4.0L Jeep engine everyone raves about.

Nissan 300ZX (Z32)

Early '90s 300ZX is sick. Twin-turbo V6, 300 horsepower, four-wheel steering, all the tech. Problem? It's all jammed into a small Japanese sports car.

Zero room in there. Like trying to work inside a filing cabinet. Even simple stuff becomes complicated because you can't get at anything. Timing belt's apparently a nightmare compared to other cars. That four-wheel steering (HICAS) is weird and complicated, and not many people get how it works, so plenty of folks just yank it out when it dies rather than fix it.

Non-turbo versions are a bit easier. But turbo with HICAS? Hope you've got tiny hands and infinite patience.

Mitsubishi 3000GT VR4

300ZX cramped? Try the 3000GT. Twin-turbo V6, all-wheel drive, four-wheel steering, vacuum lines everywhere because '90s.

Everyone who's owned one says it's absurdly hard to work on. Stuff's packed so tight you need to be double-jointed. Timing belt can take days because half the car has to come apart first.

These got labeled unreliable, but honestly that's mostly from people not maintaining them. Keep up with it and they're fine. Except keeping up with it means spending entire weekends under the hood cursing at engineers. Cool car though, can't deny that.

Jaguar XJS V12

Luxury car from 1980s Britain. That's really all you need to know.

When it's not drinking gas, it's turning into rust. Parts cost a fortune assuming you can even find them. Mechanics who work on these are rare and expensive, so better get comfortable with wrenches. V12 makes it all worse, though it does sound amazing.

Electrical gremlins, mystery leaks, random failures—standard old car stuff. Then there's all the vacuum lines that love springing leaks. Pop the hood and it's just chaos in there, hoses and wires going everywhere with no apparent logic.

People can't decide if these are horrible or actually okay, which probably depends on whether they kept up with maintenance. Either way, working on one is confusing as hell.

VW W12 Cars (Touareg, Phaeton, Audi A8)

300ZX and 3000GT had big V6s in tight spaces. W12 is basically "what if we just doubled that?"

It's literally two VR6 engines on one crankshaft. Twelve cylinders, four banks, two heads. Sounds cool, is a nightmare.

Shows up in Touaregs, Phaetons, Audi A8s. All terrible to work on. Maintenance costs are stupid because everything's complicated and packed in there like sardines. Some are twin-turbo too, because why not make it worse. Parts are pricey and hard to find since W12s are already rare.

Engine bay looks like someone gave up halfway through a really hard puzzle. Unless you really know your stuff and have all day, these are the cars where you just throw money at a mechanic and try not to think about it.

Bottom Line

Some cars want you to work on them. Others actively fight you. These five are the fighters. Not all bad cars when they're running—some are actually great—but if you like DIY maintenance, maybe skip them. Or at least go in knowing you're choosing pain.