What engines are the hardest to change spark plugs?

[StevieC]

The Ford Aerostar, Ford 3.5 / 5.4's, my 2006 Santa Fe with the 2.7 (Remove the whole plenum and all the crap attached to it), Old Dodge Caravans where the back bank of cylinders were under the windshield / firewall. Older GM Grand Prix where you had to remove and engine mount and roll the engine forward to get at the back 3 plugs. We did many where the back 3 weren't changed.

 

[Wolf359]

Originally Posted by krismoriah72
When i had my shop a friend of mine bought one of these vans and i usually let him work on things himself in one of the bays. He wanted me to change the spark plugs. I looked it up in the Mitchell estimator.. to see how hard it would be to do before i helped him.

Step 1: Remove Engine.

We had a really good laugh at that one.

I thought there were a couple other GM engines that required the engine to be removed to change the spark plugs.

Removing the intake is still out there, the newer Mercedes M276 engine with the direct injection engine has the intake manifold removed as part of the procedure to change the plugs although someone else claimed they were able to do it without doing that.

The Ford DOHC 3.0 engine could also be changed without the intake the removal if you took the back cowl off and used some swivel joints, but most people removed the intake. Good time to replace the gaskets anyway as those often leaked.

 

[PeterPolyol]

I'm so thankful to have never owned an engine with such a crappy design as to require removal of major parts/the engine itself to do plugs.

I got a 2.5V6 from the early 90s stuffed into a tiny hatchback. Had to cut a notch in the front support rail just to clear the oil fill cap but can still change all 6 plugs in ~5 minutes with only an extention.

 

[eddy21]

Originally Posted by Smoky14
Chev Monza V-8, worst I ever ran into.



Hole saw through the fenderwell

 

[supton]

Originally Posted by PFP
Originally Posted by bdcardinal
Originally Posted by milwaukee
No brainer

Ford 3v 5.4. Simply the stupidest design in the history of engines


As much as I love Ford, this by far.


Nothing worse that spark plugs that come out in pieces! Or blow themselves out the top of the hood!

Was going to say, I thought those were self changing plugs in that engine.

 

[blupupher]

Originally Posted by Rand

What ford 5.4 3v did you change? its nearly impossible to get them out unless someone did them before you and used updated parts.


2004 F150, first year of the 3v 5.4.
Plugs had never been changed, brother in law has had it since new. 154,000 miles on it.

All 8 out intact

New on left, old one on right

Just followed the instructions that Ford recommends in their TSB and they all came out intact.
Lucky I know. I had the Lisle removal tool just in case.

 

[milwaukee]

You are the 1 in a 1000. Seriously, you are the only person I've ever heard of on the net or otherwise that got all 8 out with those miles.

The one on the left looks like it left something behind.

 

[milwaukee]

It is not spark plugs but Toyota v8's have to remove the intake manifold to replace the starter. I like Toyota but that is super stupid. Now, the unhinged Toyota drones on this board will come up with a "expertly engineered" reason for this LOL

 

[The Critic]

Subaru's are annoying.

 

[Sayjac]

Originally Posted by blupupher
….Just followed the instructions that Ford recommends in their TSB and they all came out intact.
Lucky I know.
Yes, now buy a lottery ticket. Hope your BIL appreciated it with.

Props to you for your patience following the tsb.

Originally Posted by milwaukee
It is not spark plugs but Toyota v8's have to remove the intake manifold to replace the starter. I like Toyota but that is super stupid....
Seems like less than ideal. However 'for me', I don't put it in the same category as a maintenance item like spark plugs requiring intake manifold removal. That even knowing many/most sparks now good for ~100k miles.

 

[KalapanaBlack]

Originally Posted by milwaukee
It is not spark plugs but Toyota v8's have to remove the intake manifold to replace the starter. I like Toyota but that is super stupid. Now, the unhinged Toyota drones on this board will come up with a "expertly engineered" reason for this LOL


Northstars are the same. Was supposed to be for longevity, due to being more protected from the elements, I suppose.

Really isn't that terrible either way, since a '93 Camry V6 and all 3.6 FWD GM V6s require the same process for plugs.

Sure, it's more than for a starter that isn't under the intake, but...

 

[KalapanaBlack]

Originally Posted by StevieC
The Ford Aerostar, Ford 3.5 / 5.4's, my 2006 Santa Fe with the 2.7 (Remove the whole plenum and all the crap attached to it), Old Dodge Caravans where the back bank of cylinders were under the windshield / firewall. Older GM Grand Prix where you had to remove and engine mount and roll the engine forward to get at the back 3 plugs. We did many where the back 3 weren't changed.


Seen lots of Toyota V6s with the rear center plug doesn't match the rest. I'm sure they got 1/6th off... not.

 

[nthach]

Originally Posted by milwaukee
It is not spark plugs but Toyota v8's have to remove the intake manifold to replace the starter. I like Toyota but that is super stupid. Now, the unhinged Toyota drones on this board will come up with a "expertly engineered" reason for this LOL

You asked for it

My hypothesis was that Toyota was concerned about packaging the starter, since the 1UZ-FE was a "compact"(for the type, a DOHC V8) engine that had to go into the engine bay of a luxury car. Thankfully, those starters don't go out too often. GM followed suit on the Northstar V8.

The Toyota V6 plugs, at least on the COP MZ series V6s are a pain to replace. That is a very good reason to use nothing but OEM-type double-Pt or Ir/Pt plugs on those. I also replace the valve cover gasket and plug tube seals when I'm in there as well. Supposedly, on the early Camry V6s with waste-spark COP, you could leave the intake in place as the rear bank of plugs had conventional wires.

 

[nthach]

Originally Posted by The Critic
Subaru's are annoying.

Haven't touched the plugs on a 2012 non-turbo Forester yet, I thought the plugs on an 03 Forester were easy.

 

[nthach]

Originally Posted by fdcg27
We had a '97 Aerostar 3.0 so I can attest to the difficulty in changing the plugs.
Fortunately, they were plats and the recommended interval was 100K.

Wait, I thought the Aerostar exclusively used the 2.9L and 4.0L OHV Cologne V6?

I HATED doing the plugs on a friend's 98 Explorer with the 4.0L SOHC. I'm kicking myself for using NGK G-Powers versus Autolite XP/Motorcraft Double Plats/Denso Iridium TTs.

 

[LDM]

I can vouch for the difficulty of the 93-97 F-body LT1, I have a 94 Z28. With the stock manifolds it is impossible to get to the spark plugs from the top of the back cylinders, you have to get under the car and even then it is almost impossible with a special adapter. Took me about 3 hours the first time I had to change mine. Course, now the car has long tube headers instead of the terrible stock manifolds, which means its a lot easier to do. Still, they left almost no room to work on things with these cars, so the spark plugs aren't the only thing that's hard to get to. Makes working on my 89 IROCZ and truck easy by comparison though.

 

[jc1112]

Subaru is tough in my opinion

 

[milwaukee]

Originally Posted by nthach
My hypothesis was that Toyota was concerned about packaging the starter, since the 1UZ-FE was a "compact"(for the type, a DOHC V8) engine that had to go into the engine bay of a luxury car. Thankfully, those starters don't go out too often. GM followed suit on the Northstar V8.


I don't know anything about GM northstar stuff but doesn't Northstar engines pre-date the v8 toyotas by about a decade?

I had a 100 series Land Cruiser. Possibly the best vehicle I ever owned. Seemed capable of a million miles. In the Land Cruiser world the silly starter placement was claimed to be for water crossings LOL yet without adding a snorkle the air intake would be submerged well before water made it to the starter. You are probably right, its just a packaging thing but its odd for Toyota to completely screw something up GM or BMW style. And the toyota starter is almost a mandatory replace in the 100-150k mile range. At a shop its about a $900 repair when on every other v8 truck its remove and replace.

 

[nthach]

Northstar was introduced in 1993-1994. It was one of GM's more complicated engines that competed with the Germans and Toyota.

 

[Kruse]

Originally Posted by nthach
Originally Posted by fdcg27
We had a '97 Aerostar 3.0 so I can attest to the difficulty in changing the plugs.
Fortunately, they were plats and the recommended interval was 100K.

Wait, I thought the Aerostar exclusively used the 2.9L and 4.0L OHV Cologne V6?


On the drawing board, the Aerostar was designed for the 2.3 liter/4 cylinder engine. That is why working on the later V6 engines was such a task.
Beside the 2.3,during it's lifetime, the 2.8 (very early on, it's rare) the 3.0 and the 4.0 V6s manged to find their way into that space. Seriously, a healthy 4.0 will handle most things that the van is required to do.
A few entrepreneurial engineers have shoehorned a small block in there, but upgrading the front brakes is another nearly-impossible task and it's really not worth it.