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Hi y'all
Just swapped the plugs on a 2008 GD3 base with about 170k on it that I recently purchased. When I was pulling the #3 coil pack I noticed an ominous gasoline smell. Here is what it looked like when I got it all out:
Looks like a compression leak in the plug to me? The car's been running fine and the new plug seemed to thread in with no problem. There is a slight discoloration on the exhaust manifold heat shield beneath it like a little fluid has escaped but overall it wasn't very messy. I'm going to replace the coil pack soon, as the seal is pretty fragile now, so I'll pull the new plug then and see how it looks after driving a bit. Any of y'all had a similar experience? The service history's last entry is from 136k miles and they replaced the plugs then, so it's been about 34k miles on these NGK Iridiums.
I'd say... it could be similar to what happened to me with my GE8... the threads were failing.
Sure, you can thread your plug in, but as you can see, it is clearly covered over the entire length, while the other three have big portions that are not (because that's where they mate with the threads on the block).
I would guess a threaded insert might be needed to fix this.
I'd say... it could be similar to what happened to me with my GE8... the threads were failing.
Sure, you can thread your plug in, but as you can see, it is clearly covered over the entire length, while the other three have big portions that are not (because that's where they mate with the threads on the block).
I would guess a threaded insert might be needed to fix this.
Don't jump the gun yet.
It's hard to say so without actually looking on the threads.
The issue is common on second generation due to the crappy head quality, but on GD3 it is not a very common thing.
most of the time a dirty plug gasket sealing surface and use of anti seize on the threads causing this (the plug is tight but plug gasket is not sealing!)
prevention;
when changing the plug, use vacuum cleaner, compressed air or air in can top blow dust and debris out of the spark plug well
Use light and mirror to confirm clean surface
DO NOT apply anti seize to the threads (ignore manual for just that )
Use hand tightening method to assure that plug gasket if compressed (torque wrench may click before gasket is smashed)
Our number 3 plug has looked like that since the very first change at 50k miles. I've even heard combustion noise from the leaking and had to tighten that plug a few times.
Honda really dropped the ball on the cylinder head threads on the L15's. The new ones now have the longer style thread plugs that ALL modern cars use. Don't know why Honda used the shallow thread plugs in the early L15's, but that is the root of the problem.
Thanks for the advice y'all. I'll update here when I pull the plug again to see if it was just the plug itself leaking or the threading in the head. Def hoping for the former but the dirty threads on the plug leave me worrying about the later. There has not been any CEL before or after, so what danger do I face by driving it if the threads in the head are failing? Doctor J, you mentioned blowing out the spark plug well with compressed air, wouldn't you be concerned about potentially blowing filings into the engine?
I've seen youtube videos of people using air hoses to blow all the shards out... and a LOT comes out, but they're are small, and I do worry some would lodge between the side of the piston and the chamber wall.
If you have a fat drinking straw that either has a flexible portion or entirely of soft rubber, you could put that at the end of a vacuum hose and attempt to pull any bits out that way.
They're just the right size to fit through the opening for the spark plug. Big enough to guaranteed picking up anything that's likely to be in there and small enough to allow air to flow around it (otherwise it wouldn't work well).
The particles are mentioned in my reply are the dust and carbon particles (not metal shavings) collecting at the base of the spark plug well during plug service life. They typically harmless, the goal is not to have them at the place where the spark plug gasket is going.
10-17-2020, 08:01 PM
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