Spark plug discoloration (Update: new stuck bolt question)

[Mark R]

I was investigating an intermittent cold misfire on my Lexus IS250; which in reality is probably caused by carbon buildup on the intake valve, a problem that this vehicle is notorious for.

But was doing some simple diagnostics; swapping some stuff around on the misfiring cylinder.

Anyway, I pulled the plug and it's covered in rust, for want of a better word. It's one of these fancy iridium needle electrode ones, with a 60k life, so I'm not familiar with these.

It's due for a plug change in 10k, but if these are bad, I'll probably get them done early; the manifold has to come off to get to the left bank, so that would be a good a time to do the valve clean, if needed.

---

Update:
Now I'm completely boned. The end of the allen wrench sheared off flush with the bolt head and is now firmly embedded in the bolt head. Will not budge even after trying to prise it out, magnet it out, sticky-goo it out, and beat it out with a center punch.

I guess the only hope is to drill it out, but that's not something I can do - plus, the allen wrench is probably tool steel, so it'll probably need a carbide or diamond drill.

 

[kitatech]

Once pulled, replace....
Given the hassle of removing the manifold, get the Denso iridium plugs spec'd to last 100-120k miles...

 

[phucheneh]

What the hell brand is that? Silly design. Aside from that, the gap looks pretty huge, and the buildup of soot implies incomplete combustion.

Replace them with OEM-style NGK or Denso plugs and see how it does.

As far as the rust, that's kind of bizarre. Do you have some kind of cold air intake installed? I don't know what would cause that other than ingestion of small amounts of water. If it's not coming through the intake, it could be getting into the plug wells and seeping past the threads. I don't think it's coolant, as I've never seen anything close to a proper mix cause that...looks more like it's just from straight water, possibly with a bit of salt for good measure.

edit: I just noticed the center electrode is lop-sided, too. That's some pretty heavy wear.

 

[Mark R]

Those are the OEM denso plugs, with the correct part number for the car.

I'm not too sure what they are supposed to look like, as they don't look like any of the pictures on the denso site. I think they must be a special lexus OE variant.

The car is completely stock. Full dealer service history, although there was a gap when it wasn't serviced or driven for a year.

Anyway, would you still get "rust" from water, as the head, block, piston and pretty much everything else is alu on this car. I suspect it isn't rust, but is something else.

 

[Bartman39]

Not rust just combustion deposits and the color is due to the additive package for the fuel you are using... Chevron premium fuel used to give a red tint to the plugs in my 427 BBC... Ran great on it just looked weird when I did a plug read...

 

[LTC8K6]

MTBE turns plugs red, iirc.

I thought it had been phased out already though...

http://en.wikipedia.org/wiki/Methyl_tert-butyl_ether

 

[Bartman39]

Me too but the legislation was signed in 2005 but just read this down near the bottom...? Could still be another additive possibly but its not rust for sure or there would be some serious problems (engine internal)...

This bill did include a provision that gives MTBE makers, including some major oil companies,$2 billion in transition assistance as MTBE is phased out over the next nine years

Uh it also depends on where you live...

 

[Mark R]

I pulled all the plugs in bank 1 and replaced them. Misfire is gone.

The gap on the new plugs is noticeably smaller, as there should be a little mushroom on the tip of the ground electrode protruberance.

I'd hoped to do them all, but a seized Allen-bolt down a deep hole defeated me when I tried to get the manifold off. Pretty much all the manifold bolts had seized, and they needed some gentle persuasion with a hammer and a breaker-bar with a pipe on the end.

I'll think for a bit about what I'm going to do about that last bolt, because I can't get my Allen sockets on it, and I can't get enough leverage with a straight Allen wrench.

I'm hoping not to have to go tail-between-legs to a local mechanic. Anyway, it's a good enough time as any to order some new intake gaskets, so while they're on their way, I'll have some thinking time.

Also, I think I worked out what the red color is. I'd run a couple of bottles of injector cleaner in the tank. I looked up the tech-specs on the cleaner I used, and lo-and-behold it contains a hefty dose of ferrocene (oil-soluble iron), so the red color probably is "rust" or ferrous oxide, but it probably came from the fuel additive.

 

[boomerang]

I can't get enough leverage with a straight Allen wrench.

Did you try the box end wrench trick?

Box end for leverage.

 

[Mark R]

Did you try the box end wrench trick?

Just tried that now to see if I would be able to do the job at all.

Now I'm completely boned. The end of the allen wrench sheared off flush with the bolt head and is now firmly embedded in the bolt head. Will not budge even after trying to prise it out, magnet it out, sticky-goo it out, and beat it out with a center punch.

I guess the only hope is to drill it out, but that's not something I can do - plus, the allen wrench is probably tool steel, so it'll probably need a carbide or diamond drill.

 

[Bartman39]

Pic's would be help us to help you...

Also if you have access to an acetylene torch with a welding tip you can heat the head of the bolt to red hot and then cool it via a spray bottle with plain water... This most of the time will loosen both the piece of Allen wrench so it can be extracted and help release the torque of the bolt head so you can use another Allen wrench to remove it... If you need a drill bit for tool steel then use a cobalt bit...

 

[Mark R]

Can't heat it up. The manifold is plastic.

And it's down a narrow hole, so access is difficult:

Plus I've hammered at the broken bit of wrench enough that the head of the bolt is wrecked.

I'm pretty sure the only way to get it is to grind the wrench out with a carbide burr, and then drill the bolt enough to get an EZ out or similar removal tool into it.

I suppose an alternative would be to grind the whole bolt head off, take the plastic part of the manifold off, and then attack the rest of the bolt once the manifold is apart; failing that, drill out the bolt with an oversize hole and tap some new threads into the bottom part of the manifold and drill a clearance hole in the top.

I fear that this is going to be beyond my tools and capability, and I think I'm going to have to cut my losses, and pay someone to do it.

Question to pros: How much should I tip a mechanic for bailing me out of a screw-up of my own creation?

 

[NutBucket]

EZ out looks like it would work well given the head is all there.

 

[Bartman39]

EZ out looks like it would work well given the head is all there.

Agreed... Just drill the rest or most of the Allen wrench tool out so an EZ out can be used... Or if all else fails drill the head of the bolt off and remove the manifold then remove the remainder of the bolt...

Last resort or if you just think your done take it to or have a mechanic (by trade) remove it for you...

 

[Mark R]

Agreed... Just drill the rest or most of the Allen wrench tool out so an EZ out can be used... Or if all else fails drill the head of the bolt off and remove the manifold then remove the remainder of the bolt...

Last resort or if you just think your done take it to or have a mechanic (by trade) remove it for you...

Just checked my dremel tool, and it's dead. Motor seized.

I think this is nature's way of telling me that I'm done.

 

[phucheneh]

How in the world? Were you using the wrong size allen wrench? Or a ball allen? I dunno how else you would break that.

I would generally never use a regular bent allen wrench on a car. For that, dedicated sockets. In a pinch, a bit set works, but they're typically not as strong. I'm guessing you used the long end of that wrench and torqued it until it started twisting. Not to rub salt in the wound, but an allen socket on an average-sized cordless impact driver would probably have snatched that bolt out with zero effort.

EZ-out is a good idea if you want to add a broken extractor to that mess. Otherwise, left-handed drill bit. If it doesn't start to spin out, keep drilling untill the head pops off, then use a smaller bit to make a hole in the center of the bolt and use an extractor. I'd probably just drill the whole bolt, though; I bet it's fairly soft.

Then heli-coil it, unless you manage to be such a smooth operator that you can just chase the hole with a tap of its current size. That's rare, because it requires drilling a perfectly-centered hole with the perfect-sized bit. I've done it on occasion, which usually results in a loud proclamation of I AM THE SMOOTHEST MOTHERF*CKER ON THE DAMN PLANET HELLS YEAH.

...but it's rare.

 

[Mark R]

Used the correct Allen wrench. Just torqued up a bent Allen with a big wrench.

The Allen tore up the head and lodged in, shearing just proud of the surface of the bolt.

Guess there was just too much torque on a cheap wrench.

Next time I'll use an impact driver.

Oh well, I'll see how the pro digs me out of this hole.

 

[bruceb]

Might be easier to just bust up that plastic manifold and replace it after the bolt comes out. And just so you know, they make allen keys in both American and Metric sizes. You may have used an American size spec allen key on a Metric hex size (Japanese car, most likely metric)

 

[Mark R]

The plastic manifold is a $750 part. I'd like to avoid damaging it.

 

[Fritzo]

Spark plug rust is normal, especially in areas that get snow. Salt eats them away very easily, which is why it's important to keep your car clean in the winter.

Also, if you have an aluminum block, the two dissimilar metals will form a "battery" and cause corrosion. If your plugs get rusty, just change them.

The only time you have to worry is if you have black or white residue on your electrodes. This will indicate your engine is running too rich or lean, but this is less common with today's computer controlled fuel injection systems.

As for your broken plug, there are special tool kits to do that. Check your local Autozone and they'll probably loan one to you.

 

[imagoon]

That looks like an aluminum bolt. I would just drill it slowly until it was about to pop off an then use a small chisel [screw driver if you want to shade tree it] and a hammer to pop it off. Then use an easy out to back the left over stud out.

 

[Mark R]

Woohoo. I fixed it.

I found an old scrap 3/8" hex socket. It bit, but not hard enough to shift the bolt.

So I filled it with polar-bear aquarium grade epoxy putty and hammered the epoxy-filled socket onto the bolt. Let it sit overnight to cure.

Popped right off this morning with a ratchet.

 

[exdeath]

Woohoo. I fixed it.

I found an old scrap 3/8" hex socket. It bit, but not hard enough to shift the bolt.

So I filled it with polar-bear aquarium grade epoxy putty and hammered the epoxy-filled socket onto the bolt. Let it sit overnight to cure.

Popped right off this morning with a ratchet.

:thumbsup: for inventiveness.

 

[imagoon]

:thumbsup: for inventiveness.

Guess that works. Now you can burn the epoxy out with a blow torch!

 

[slag]

Great Job!