Dirt in spark plug threads - 2004 F150 4.6L V8

[NilsonCain]

I was about to change the spark plugs on this engine (4.6L V8 Ford) and I removed the coil/boot from the left front plug and noticed a lot of dirt buildup around it, so I used the air compressor and a blow gun to remove any debris before proceeding further.

I then unscrewed the plug, and noticed it was pretty difficult to turn almost all the way out--had me scared of a misthreaded plug. Then I noticed greasy dirt ground tightly into the threads.

Obviously the idiots who serviced the truck previously didn't bother with getting the dirt out of the way first.

My question is this: whats the best way to clean the threads in the engine? I was thinking use brake/carb cleaner liberally to soak the open hole, then turn the engine over without the plug in to get as much of the **** out of the cylinder as possible before reinstalling the plug; one at a time.

 

[01rangerxl]

Can you reach down to the plug hole and clean it manually with a piece of a rag or something? Personally I wouldn't want to just spray solvents into the engine.

A gun cleaning kit may come in handy for this.

 

[Chris142]

Fire it up with the plug out. If that don't blow the junk out nothing will. I would not flush it down unless I had no other choice.

 

[LargeCarManX2]

Q-Tip with grease on it! Vacume the spark plug hole as well!

 

[tommygunn]

Thread chaser or, yeah. Floor the gas pedal so the injectors don't fire in clear flood mode and turn it over.

 

[NilsonCain]

There really isn't any way to reach down in there, it's a pretty deep hole. The gun cleaning brush is a good idea, I think I'll try that with some motor oil on it, then fire up the engine without the plug in (one at a time).

Hopefully that will do the trick.


Thanks!

 

[AVB]

I have a insert kit to repair blown out spark plugs. 1 part of the kit is a rubber stopper with a small hose attached and a valve and milton type fitting at the other end. It is used to check when the valves are closed. The rubber stopper with a few wraps of elecrical tape fits snug in my small shop vac hose. I take the valve off the other end and use it to vacuum out the cylinders after drilling and tapping the spark plug holes. Then I spin the engine over with the spark plug removed.

A thread chaser coated with grease may catch some of the dirt and clean the threads at the same time. I coat the drill bit and tap with grease instead of cutting oil and it keeps most of the shavings out of the engine.

 

[KB2008X]

Ford's 4.6 & 5.4 engines have a colossal design flaw regarding the spark plug threads. The spark plug holes have just three threads with which to hold the spark plugs. On top of that they are aluminum cylinder heads.

Doing anything that might affect those three threads in any way is a really bad idea. I wouldn't put anything inside the spark plug holes.

Ford, as you would expect any manufacturer to do, has denied any problem on their part, even though it has been ongoing issue for nearly two decades now.

Here is a link to a bulletin put out in 2005 by an engine rebuilding association. Similar warnings have circulated for years within the repair industry.

http://www.enginebuildermag.com/Article/1071/tech_notes.aspx

Keith

 

[MarkM66]

I've duct taped a piece of fuel hose to the end of my shop vac attachment to suck things out of places like that.

I'd clean it out manually, by rag on a stick, q-tip, etc., then vacuum out anything that may have fallen in the hole.

 

[Mud]

Originally Posted By: MarkM66
I've duct taped a piece of fuel hose to the end of my shop vac attachment to suck things out of places like that.

I'd clean it out manually, by rag on a stick, q-tip, etc., then vacuum out anything that may have fallen in the hole.


^^ This ^^ works great

 

[LeakySeals]

I lose sleep over that every time I change the plugs. Wondering if I'm scoring the cylinder walls, wearing out the rings with sand. Mechanics figure if your going to them, you wont ever look, and if you do its years later. Not a slam to all of them, but a few bad apples can damage the creds of the good ones.

Anyways, depends on how deep the plug hole is what you can get in there. Probably not the best way, but what I do is tape a rag to something long enough but thin enough to get in the hole. (extension, long screwdriver, etc). Soak the end of the rag in aerokroil, P-Blaster, etc. Put it in the hole. Push the rag down so it "scrunches up", filling the hole to the threads. Twist left, as if you were removing a plug. Pull the rag out, should have the crud stuck to it.

 

[NilsonCain]

I finished all the plugs... I removed each boot, used the air gun to blow out debris, sprayed carb cleaner, used air gun again, as well as the shopvac+rubber hose to remove debris.

Removed plugs (all were full of dirt/sand in threads), sprayed more carb cleaner, used 20ga. shotgun brush to scrub threads, used more carb cleaner along with blow gun and vacuum hose again to remove debris, then installed new plugs and replaced boots.

Plugs were replaced one at a time. I did a test-start after doign all four passenger-side plugs, and engine ran fine. After all 8 were done, I started the engine and have a bad knocking noise on the drivers side (cant tell which cyl) that sounds like something bouncing around in the cylinder or a valve slamming the seat.

Engine was running like [censored] as well. Will be removing all drivers side plugs tomorrow night to see what I tore up

 

[AVB]

I did a tune up on a Expedition today. Some one had installed the wrong type insert in the #2 cylinder to fix a blown out spark plug, the insert came out with the plug. I had to reinstall it with the same plug. The insert wouldn't come off the plug and the owner only gave me 6 plugs said 2 had been "repaired" recently. He didn't know which 2 it was, he just bought the truck. The inserts I have are a different thread pitch and I don't have the oversize kit to repair these patch jobs. The insert screwed in to far when I put it back in and the piston was hitting it.

I doubt that is what your problem is, you could have knocked some carbon loose from around the spark plug hole on the inside.

 

[NilsonCain]

I'm going to pull all the drivers side plugs back off tonight, see if I can tell what's wrong... Im pretty certain I torqued all the plugs down.

I'll pull all of them out and turn the engine over with open plug holes as well.

Really hoping its nothing bad. It sounded really rough.

 

[NilsonCain]

Well I removed/reinstalled the drivers side plugs like I had planned, and it started right up and ran fine.

The plugs were extremely tight though; I didn't screw them in that hard. I'm thinking that the carb cleaner had greased the threads and led to them being tightened more than spec... whether that caused noise, I dont know.

There has been an audible ticking from the top end, which I attribute to running synthetic instead of conventional in there; probably a lot of [censored] to clean out. The noise has pretty much disappeared after a day of driving.

I will need to replace the PCV valve as I accidentally broke it during the whole fiasco. Picking that up in the morning. I've got the vacuum line taped off for now, but the idle's a bit rough in that condition. After the PCV goes in, it should be all good.

--

This truck's got around 148,000 miles on it, and has been run on Castrol GTX 5w20 its whole life as far as I know, with undersized quick-lube filters and ~5k oil changes. It's used to haul a trailer with three horses quite a bit, and I've used it to tow vehicles as well. It's worked pretty hard. I think the clean air filter, new plugs, Quaker State Synth 5w20, full size Motorcraft filter, and new PCV valve, will make it happier.

 

[morris]

now i remember why i didnt drive fords.

 

[KB2008X]

Congrats Nilson, sounds like you may have dodged a bullet there.

Keith

 

[01rangerxl]

Glad you got it sorted out!

 

[01rangerxl]

Originally Posted By: morris
now i remember why i didnt drive fords.


Funny to hear from someone who owns a Dodge Dakota. Just kidding.

 

[SOHCman]

The spark plug thing wasn't a problem on the 5.8 was it? I think its got iron heads anyway.