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1970s Urban Legends: Cars that required engine removal to replace spark plugs?

But then there was THE 383 Interceptor. All the others are just something less.

Minivans of today pretty much need the engine removed to get to the plugs.

I guess this isn’t much of an issue b/c of the 100k plugs, and that kids grow up, and few people drive these things more than 100k. (OR, they’re so trashed in 5 years that people get another one?)

Thanks for the great nightmare spark plug stories…great stuff. Lots of knowledge and experience here!

I can’t speak for changing plugs, but I helped a friend change a starter on his V6 Chevy Monza and it was like one of those brain-bending puzzles made out of steel, where there’s only one way to twist and turn the two pieces to get them to separate.

I can’t think off the top of my head any engine that must be removed for a plug change but there are a number of them that might lead you to think so. :slight_smile:

My oldest son still has his 96 Camaro with the 3.8 and the 2 rear plugs on the passenger side are an absolute pain in the neck to change due to the location of the O2 sensor and the evaporator case. The O2 blocks the center plug and there is only enough room between the exhaust manifold and evaporator case to insert part of a flattened hand. They have to be done from underneath and while I have done it alone it’s easier to have someone up top to help out.
The driver’s side center plug is also blocked by an O2 sensor and a ratchet cannot be used due to the proximity of the O2s. One has to weasel a socket with a hex onto the plugs and use ( very slowly) an end wrench to work the socket.

While not plug related, a guy came to me once about replacing a starter in a car I had never laid hands on before. After an hour of contemplation I could see no way of accessing the starter and located a manual. The book said the engine and transmission must be removed to swap the starter out and the owner did not want to go this expense. With his permission and blessing, I removed the carpet on the driver’s side and cut a hole underneath the clutch and brake pedals; fishing the starter motor out that way and then cutting and riveting a plate back in place to cover the hole. This was on a Renault Le Car.

IIRC, the 1950s 2-seat T-birds with the V8 needed the engine lowered to get at the 2 rear spark plugs. And the FWD GM cars, including minivans, need to have the top motor mounts removed so that you can rotate the engine forward to get at the spark plugs. It’s not a difficult job in a car, but the minivan engine is under the cowl above the engine bay.

The Monza you had to loosen the engine mounts and raise the engine up to get to the back plugs. Royal pain in the but you never had to remove the engine.

The Vega was a small 2.3l 4-cylinder. The plugs were extremely easy to replace. The Monza was the replacement for the Vega. I knew of several V8 Vega’s…was it safe?? Depends on how well it was done. Some were done right…A few were done very wrong.

 Well, although I never owned one, I'm sure it was tight to get to the plugs on the 454 Nova SS or Chevelle SS, or the Mustangs and etc. where they had to cut the shock towers to get the engine to fit.

 My first car, a 1972 Cadillac (I got it in the late 1990s) had scads of room under the hood.  I think the most room under the hood I've ever seen was on a Chevy Apache pickup.  Probably 3 or 4 people could habe ducked under the bumper and stood in the underhood area, this area was very large but also it had a pretty small inline 6 cylinder engine in it.  My friend did duck under and stand next to the engine when he did plugs etc. on it.  

 I have had several problematic cars though.  I had a 1985 Chevy Celebrity, where although the plugs were "towards the front", the A/C compressor bracket was right over one plug.  Man it was a pain!  The official method was to unbolt the compressor and bracket, let 'er rip with the R12, and put some new R12 in there when you're done changing the plug.   I could just get the plug replaced (without moving the compressor)  with a thin-walled socket, a thin socket driver, and a wobble adapter.  I did manage to not tighten the new plug up properly one time, so it loosened up and shot right out of the block. The plug was still on the plug wire so when I stopped and popped the hood it was just hanging there..  I was very near a parts store, so I pulled in there and brought in the plug, I put on some  winter gloves due to the heat.  I set it on the table, and commented it was pretty hot.  It was pretty obvious, it discolored the bit of advertisement it was sitting on.  He leaned in and looked at it.  That plug tip was all crazy looking and detonated, the tip was pretty eroded and little spheres of tip-metal had spattered onto the rest of the plug end    Unfortunately he called the other parts store guy over and first thing he did was picked it up.  He dropped it pretty quick and went back to run some cold water on his hand.  The 2.5L 4-cylinder was cast iron block and head, so once I replaced the spark plug (and double checked this time) everything was fine.

 Currently... well, it wasn't just the 70's models where the 3.8 needed some manuevring.  I have a 2000 Buick Regal, and the 3800 on it needs to be tilted to get to the rear bank.  that whole bank is right up against the firewall.  Mechanics charge a minor fortune to do plugs & wires on these things, so I was going to do it myself. but I took a look and realized there was no way to "cheat" on this car like there was on my Celebrity.

I know it is very common for people to rock the 3800 motor forward to change the rear bank of plugs, but the last two I did in recent memory (a '98 Bonneville and an '02 Grand Prix) I did without doing any such thing, and it took 35-45 minutes to change all six plugs (it was still a pain in the butt, and the knuckles). I seem to remember rocking the engine forward on one of these cars and realizing it makes very little difference in the amount of room you get. to work.

Slightly off topic: I do agree with Caddyman as to keeping his Allante. The Allante was a beautiful car, and a joy to drive. The whole car is a work of art. Even the engine looks like a beautiful aluminum sculpture. If I had one, I would have a really hard time finding any reason to justify getting rid of it. Maybe for a disgusting amount of money, but no other reason would work.

My first car, a 1974 Cadillac, had enough room under the hood, even with a 500 cid V8, that you could almost curl up under there and nap. Or keep a spare Prius there for emergency transportation.

But I seem to remember that the passenger side back plug was a pain to get out–as I recall, part of the HVAC system was in the way.

The easiest by far that I’ve owned is my old 1994 Chrysler LHS–all the plugs are right on top, pretty much vertical, and accessible through tubes in the valve covers, hemi-style. With a long extension, they come right out, no problem. I can do the whole set in 20 minutes or so. One of the worst I had was an 80s Ford LTD–The passenger side back plug was horrid to reach as I recall. You pretty much had to just pack a lunch and expect some lacerations to get that one out.

A Sunbeam Tiger, an Alpine with a Ford V8, definitely needed the engine removed to change the plugs.

The 1968 Mercury Cougar with the optional 390 cubic inch V-8 was a very difficult car to change the spark plugs. It seems to me that the engine mounts had to be disconnected so that the engine could be raised. There were rumors around that the 1975 AMC Pacer had to have the engine pulled to change the rear spark plug, but I changed the plugs on my 1975 Pacer without any real problems.

I was told the fiat x19 was one of those mid engine cars that needed at least an engine lift to get at all the plugs.

For ledhead75: My 1990 ranger also has 2 plugs/cylinder. The reason is 2 ignition points promotes a more even flame front across the piston thereby reducing the likelyhood of pinging. Yeah it was a surprise to me also when I worked on this used car purchase. Personally, I’m happy I don’t have to do something like remove the manifold to get at those hard to access plugs - that would be a sign of really bad design. Next time you encounter such a problem, be sure you have what’s called “wobble extensions” for your sockets. They are a 100x better than the old flexible (u joint like) adaptors (too floppy and bulky).

Speaking of engine removal or the like …
I had a 911 Porsche with mechanical valve lifters which had to be adjusted very precisely, and spent many hours going from the flat-on-the-back to the strain-the-bent-over-back positions because the adjusting cams had to be adjusted from the top and tightened on the bottom (or vice-versa, I forget which). My mechanic used to remove the engine not because he had to, but because it was far less time consuming and easier on his back.
I also had a Mercedes 280 SL “Pagoda” and when you removed the valve cover on that one, you find it lacks about half an inch to clear the hood latch mechanism on the firewall. My mechanic places a jack under the subframe just enough to bend it forward for that half inch. The car could easily have been designed with the hood latch in another place, but as my mechanic says, “Yep, these cars are engineered like no other, you betcha, and that’s why it costs you the big bucks to pay me to fix 'em.”

Any V8 Monza from the late 70’s was a bear to replace plugs without jacking up the motor, as several posters correctly identified. The V6 models were tight but accessible without unbolting anything. 93 to 2002 Firebirds and Camaros were pretty awful, too although past the 70’s. I also had a 93 SHO Taurus with the DOHC V6 that required the removal of the entire intake manifold to reach the rear 3 plugs. At least these modern examples don’t need plug replacement at 10,000 miles. Having once worked as an engineer for GM, the cars were designed to be built by blind monkeys shaking a brown paper bag full of parts so that a fully assembled car pops out. No insult to monkeys, but the easier it is to assemble, the less rework or warranty returns are required. During the 90’s and 2000’s, GM improved productivity by, oh… 300% while making cars much more complicated for safety, emissions, durability and customer demanded goodies. Service access will take a backseat especially if the component life is improved.

 It's a little better of late -- the car cos are using computer models to avoid this kind of issue to some extent.  In the case of the Mercedes 280 SL hood latches, if they designed it now the hood latches probably would be moved that half inch, or shaped differently so the valve cover would just clear.  On a newer Chrysler, a friend asked for help working on it, he couldn't get some bolt off.  I took a look, there was a bracket in the way, except it wasn't... there was a socket-shaped hole right through it so it took maybe 45 seconds to get the bolt out.  He'd kept trying to work around the bracket instead of through it.

I recall that a big-block C3 corvette with stock manifolds put one plug directly under the master cylinder, but this problem isn’t limited to old cars…

2000s Chrysler Minivans with V6 engines are fun too. I don’t know how regular mechanics do them without lifting the engine. There’s a gap along the rear bank exhaust that I can get my hand and arm into (the engine has to be cold, naturally), and manipulate the socket and extension so I can get a ratchet on them. I need the car really high in the air to get my arm angled right.

I had a 1975 Pontiac that needed the engine practically pulled out with chains before we could change the spark plugs on the right side…I didn’t get a tune up after that experience for almost three years!

I’ve often wondered why cars couldn’t be designed so that the hood and fenders tilt forward so that one could walk right up and service the engine. If the manufacturers could design a cab-over-engine truck where the entire cab was tilted forward to work on the engine, certainly such arrangement could be done on a car. There could be a small hatch as well where one could access the dipstick to check the oil and add coolant or windshield washer fluid if necessary.
I remember the Buicks made from 1941 through 1952 that had a hood that could be opened from either side or removed entirely without tools for more major repairs. I read somewhere that the Buick engineered the “nailhead” V-8 engine for its 1953 models to a width that would fit between the fender wells of the body and make spark plug changes easy. My 1954 Buick had this engine and it was easy to service.

My ex-wife’s mother had a V8 Monza, around 1976. Every time it was taken in for a tune-up, the mechanic would report he had changed 7 plugs. The only way to get to the 8th was either to loosen the engine mounts and push it around, or get a hole saw and drill through the wheel well.
I had a 1990 Olds Cutlass Supreme with a V6. Transverse mounted, and too close to the firewall to access the 3 plugs on that side. The first time I took it to a shop for a tune-up, the mechanic came back and asked if I had something else I could be doing for the next couple of hours. Instructions I saw said to remove the two engine mounts in the rear, loosen the other, and jack the engine up to tilt it forward to be able to get a socket with a long extension to the plug.
I also recall I had the horn start blaring unexpectedly one day … and I found that the fuse box in the engine compartment had a diagonal support strut that was in contact with the cover, making it impossible to remove the cover and get to the fuses without taking the strut off.
That was when I stopped working on my own cars! Also, I had company cars for the next 17 years, so they took care of all maintenance. I’m just now starting to do my own maintenance again.