Broken Spark Plug Electrode (positive)

[gatzdon]

Background Info.

2000 Ford Explorer 4WD 230,000 miles V6 OHV (X for engine code)

Problem;
Last week, my wife commented that the vehicle was vibrating. On Thursday, I test drove it to put some gas in it and really didn't feel much for vibration, but it did run a little rough. I figured it was due for a tuneup and planned on doing it this upcoming weekend. On Saturday, she told me the check engine light came on. Sunday, I pull the OBD codes and get a single code P0303 (misfire in Cylinder 3). I have her drive a different vehicle for work yesterday and park it in the driveway until I could get to it.

Yesterday, I pick up plugs, wireset, and coil pack (just to have on hand if I do need to swap the old one out). I start changing the plugs and I can see the positive electrode tips were worn down. I'm assuming that this is going to be the cause of my misfire until I get to cylinder 3 where I find the entire positive electrode is snapped off from about ½" inside the plug (see picture).

http://i195.photobucket.com/albums/z106/gatzdon/BrokenSparkPlug1.jpg

I'm assuming it cracked/fell off when she first reported the vibration. The vehicle was probably driven for almost another 100 miles before I parked it and told her should couldn't drive it anymore.

My question to you guys is this. How would you proceed?

The engine has 230,000 miles on it. I can't see it really being worth the money and/or effort to pull the engine apart to take the head off and look at the cylinder and piston. I figure if I take it that far apart, might as well get it rebuilt. Since the engine was running decent prior to this incident, I would like to weigh all my other options first.

I assume there are two possible scenarios here.

1. The electrode is still inside the cylinder and putting a new plug in to start the engine could still cause serious damage to the engine. I plan on picking up a 24" lighted boroscope from Harbor Freight Tools in order to look inside the cylinder. I will rotate the crank until the piston is at the low end. I know this won't allow me to see if anything is embedded in the cylinder head, but will allow me to see if there is anything still in the cylinder loose. I'm assuming at this point that the porcelain has already been pulverized and done what ever damage it's going to do to the cylinder walls. If I find the electrode is still in the cylinder, hopefully I can remove it with a rare earth magnet. I also believe that if it's still in the cylinder that there's a very good chance that the valve seat has not been damaged.

2. The electrode has already been blown out the exhaust valve. In this scenario, there is little risk of further damage to the cylinder, but the cylinder walls/piston/valve seat may already be damaged. I realize that even if I don't find the electrode in the cylinder with the boroscope, there is a chance that it is embedded in the cylinder head and could still come loose at a later point in time. If the electrode was blown out the exhaust valve, there is probably a good chance that the valve seat has been damaged and a remote possibility that the valve itself has been damaged depending on how much porcelain was still on the electrode when it blew out.

I know I've written a small novel here, but I'm trying to think this through thoroughly before I even consider taking the risk of starting the engine again or go through the trouble to remove the head.

So as of today, My current plan is to

= Buy the boroscope and look in the engine.
= If I see something, lower a rare earth magnet. Don't know if this will work as I don't know how much steel or nickel is in the positive electrode. I know there is nothing magnetic at the tip, but since it broke off so far into the plug, I'm hoping there's some steel or nickel that was used and is still attached. If I can see the electrode in the cylinder and it's not magnetic, I'll invest in a claw to reach in and grab it.
= Do a compression test to determine how much damage has already been done.

I'm posting to see what other suggestions/approaches anybody here might have on how to proceed.

On a side note, I've been searching via google for info on this and what other people have done, and it would appear that in almost every case of an electrode breaking off in the cylinder (positive or ground), it was a bosch plug involved which is what this one happens to be.

 

[Spdrcer34]

THESE are currently 99.00 at my local Home Depot. Pricing in YOUR neighborhood may vary.

http://www.homedepot.com/webapp/wcs...Id=10053&productId=100608589&N=10000003+90401

Ryan

 

[gatzdon]

THESE are currently 99.00 at my local Home Depot. Pricing in YOUR neighborhood may vary.

http://www.homedepot.com/webapp/wcs...Id=10053&productId=100608589&N=10000003+90401

Ryan

That is awesome. Thanks. At least now I know I can return it if it doesn't work out.

 

[celly]

Yet ANOTHER reason NOT to use Bosch plugs in our rides (the documented cases of reasons why keeps growing).

Good luck solving your problem. Make sure to use Motorcraft/Autolite plugs if you manage to salvage her.

 

[bluestream1]

I would guess that electrode is long gone. If it were me I would not even buy the scope, this happens more than you think. If it was going to do any damage it would have done it by now. Compression check the cylinder, and put in some new plugs and be on you way...

 

[gatzdon]

Well, the rigid camera was too big to insert in the cylinder and I couldn't see anything of value just sticking it up to the spark plug hole.

So I took one of the other spark plugs and and broke off the positive electrode for reference.

The bulk of it is porcelain which I think is a fair assumption was easily pulverized by now. The electrode itself had a copper core and a silver non-magnetic outer layer. So there is no way I could get it with a magnet. But seeing it for what it is, about the equivalent of a ½" length of 12 gauge wire, I'm feeling a little better about it going out the exhaust valve.

If I don't think of anything else by tomorrow, I"m going to put the new plug in and fire it up.

Thanks for the feedback guys.

PS. DON"T USE BOSCH SPARK PLUGS!!!!!!!

 

[bluestream1]

It may have also burned away slowly over time...

 

[my98nnj]

That electrode is long gone, burnt up, made history many miles ago.
Put new plugs in it and enjoy the new performance your going to feel.

 

[gatzdon]

So, put Motorcraft Platinum plugs in the engine, changed the spark plug wires and then the following happened.

= Tried to start engine, would not start.
= Looked up Firing Order Diagram and it indicated that I had two wires crossed.
= Changed wires to match diagram, still would not start.
= Thought about it and was pretty confident that I had not switched any wires around and put them back the way I had them. figured I may have looked up wrong engine on internet.
= after a few seconds of cranking, engine started.
= engine would run rough at low idle, but revved up OK.
= Went to test drive it and engine had zero power.
= Changed plugs back to match diagram found here

= Cracked on and off for a few minutes. No sign of attempting to start.
= Disconnected Battery for five minutes to delete Keep Alive Memory.
= Still no start

It was too dark out to start looking over the engine to see if I had knocked anything loose while routing the driver side plug wires. But in thinking it through, the engine had started so engine wiring, controls, fuel, etc.. had to all be working for it to start up on 4 cylinders.

Someone suggested to me that I may have flooded it and that by waiting until today, it may still just start up for me.

When I get home, while it's still daylight, I'm going to double check for any wires/vacuum lines that I could have accidentally knocked loose.

Just wanted to see if there were anymore suggestions. Should I hold the throttle wide open when first trying to start it if it's possibly flooded?

 

[offroadjosh]

Just to ask, did you gap the plugs?


Josh

 

[caveman55]

I had the same problem with my sons 01 Ranger 3.0l. When his wouldnt start I retraced my steps and his coil pack wiring was 180 degrees out from the diagram.

 

[bluestream1]

Gatzdon, do you have any issues with the engine using coolant? When the porcelin on a spark plug burns away, its a sure sign of a cracked head and coolant into the combustion chamber. I would pull that plug out again in 3-4 weeks and have a look

 

[gatzdon]

Gatzdon, do you have any issues with the engine using coolant? When the porcelin on a spark plug burns away, its a sure sign of a cracked head and coolant into the combustion chamber. I would pull that plug out again in 3-4 weeks and have a look

Just an update for those following (if there is anyone).

I flooded the engine when I had the wires crossed. I put the gas pedal to the floor to open the throttle, cranked it for 5 seconds and she started right up (with a woomf of course).

As for the coolant, it's definitely a possibility. About 10,000 miles ago, the radiator cap was leaking. I discovered it when the engine "overheated". At the time, the coolant did boil over and it was driven about ½ mile to a gas station. Water was added to the radiator and the engine started to bring the temperature down. The temp did come back down fairly quickly. That was in Canada and we drove it another 500 miles afterwards.

I traced the leak to the radiator cap and replaced it. Since then, the coolant level has been stable with the radiator full and the resevoir level not changing.

I never even thought about the spark plugs until now, but I'm guessing that the overheating is what made them brittle. I could check the plugs in about a month, but I'm not sure I would be able to spot a "brittle" plug. I guess that since the engine is this old, I can switch to changing the plugs every 30,000 miles.

I'm guessing that given the mileage, that this is the beginning of a downward slope for this engine. I still believe that I could get another 100,000 miles out of the engine, but I also imagine that will come with higher maintenance costs.

On another side note, since I flooded the engine and then let it sit for 24 hours flooded, there's gas in the oil. I noticed it when we drove the explorer for 30 miles yesterday (first significant distance since this episode began) and I could smell oil. I pulled the dipstick and could smell gas in the oil. Since it was late, I told the wife it will be parked for one more day until I can change the oil tonight.

 

[bluestream1]

Just drive it an see what happens. They all seem to use a little coolant now and then. If the head has a small crack, they can sometime seal up the crack when the engine gets hot. It will only consume coolant when the engine is cold.

 

[chance942]

How long did you wait at the filling station before adding water to it?

 

[gatzdon]

How long did you wait at the filling station before adding water to it?

I tried to cool it down as quick as possible without damaging anything.

I turned the engine off, open the radiator cap, some coolant boiled out, added water to the radiator, started it back up, the needle came down a little bit and more coolant boiled out, I added more water to the radiator, while it was running, etc....

All in all, it was about 2 to 5 minutes from when I opened the radiator cap to when the temperature stabilized where it should be. I topped off the radiator and reservoir with plain water and drove it home (several hundred miles).

When I got home is when I determined that the problem was the radiator cap leaking and replaced it.

I always assumed that there was a risk that the head became warped or cracked, but since then, the reservoir level has been stable and the radiator full.

I changed the oil. It was golden colored before the spark plug change and black when I changed it so I imagine the oil pan got a nice cleaning. I can still smell a faint hint of burning oil under the hood, but not as noticable as before I changed the oil. Don't know if it's always been there and I'm just noticing it now, but I'm going to give the engine a better look over as it could be as simple as a leak in a valve cover.

 

[chance942]

That's true,let's hope man. About your plug. I had a Nissan that I used to abuse in the Colorado high country. It was running funny so I did what I always did,checked for loose plugs. They always backed out on that engine. This time I had one that had had the electrodes totally burnt off and I sh*t you not the threads where gone,burned off at a 45 degree angle. I was baffled and some aviation guys I know(nam era) had never even seen anything like that. We agreed that it had to have been blow buywhat else right? Anyway I replaced the plug and the truck drove fine as long as I kept an eye on the plug torque. I didn't have any problems with the threads on the head which makes no sense.

I think continuing to drive is fine for you. Like already said on here any metal is long gone out the tail pipe.

 

[gatzdon]

OK, the burning oil smell is concerning me a little bit. I can see the valve leaking by a little bit slightly increasing the pressure under the valve cover, but in my experience, leaking valves would actually cause the oil to 'blow out".

I'm going to degrease the engine a little, put in new PCV valves, and torque the valve cover bolts. After 230,000 miles, I'm guessing that the valve cover bolts have backed out a little as I can see some oil on top of the valve covers. I'll degrease it to make it easier to see if there is a noticeable oil leak from the valve covers.

Once again, thanks for all your help guys.

 

[chance942]

That is exactly what happened on my 300 Str8 6. PCV was plugged. It was a PITA on that engine to change the valve cover gasket but with a new PCV,gasket and some permatex,no more oil leaking out. Truck had 255,000 or so when I did that.

 

[gatzdon]

Not to leave you guys hanging (as anyone is actually following this.

Valve cover bolts were tight. PCV valve was clean and moved freely.

But, years ago while changing the Differential Exhaust Pressure Sensor (may have gotten those words in the wrong order, I snapped off the top of the Oil Dipstick. Ford wanted $30 for a new one, so I said screw it because it still worked, it just didn't have a handle anymore.

Well, upon closer inspection, it looks like the O-Ring on the dipstick doesn't seat as well as it used to and I believe the "burnt" oil smell may be originating from them. I pushed the dipstick in farther than it should be, but now the O-Ring is clearly sealing and that smell is pretty much gone.

Maybe I'll get bored one day and and hit a junk yard for a new dipstick, but since the current one works, I have trouble justifying the time and effort for that since it's a cruise to the nearest junkyard. Last time I called around, nobody close had one, but with the cash for clunkers, I imagine that may have changed in the last few months.

Thanks for all your help and support everyone.