mre2000

Was driving the car home a few weeks ago when it began to miss... went on like that for a few minutes then the car suddenly turned into an overpriced lawn mower. Still ran but lost power, sounded and felt like an extreme loss of compression. It was obvious there was some sort of catastrophic failure so pulled it over and towed it home. When I started tearing things down I found the following: No 2 cylinder (I believe? cylinder on front left looking at the car from the front) had completely annihilated the coil and coil boot, and the spark plug came out in pieces. After carefully getting everything cleaned out, I began replacing spark plugs and coils, only to find that the No. 2 cylinder wouldn't take a new spark plug. Hmmm. After some head scratching I ran an endoscope through the valve cover and down into the cylinder head and found a definite discrepancy in the bad cylinder versus a good cylinder. Initially I thought the spark plug thread remained in the head but the damaged plug had the thread intact, it was the insulator and electrode that was blown to bits. I'm trying to figure out where to go from here. Not sure if theres some sort of sleeve in the head thats damaged or if theres something I need to try to extract before I can get a new plug installed. Here are close ups of 2 cylinders, a good one on top, the bad one on the bottom. I don't want to start tearing the engine down unless necessary, but starting to believe thats what needs to happen. Figured I would try here first. Any advice or insights into whats going on here? Thanks in advance!

Soirry this is a '98 ES300

mre2000

BUMP... no informed opinions about if / how spark plug sockets are sleeved?

LeX2K

It is honestly hard to tell from the photos. In the bottom photo it looks like something is there that should not be but what?

Hayk

iTrader: (1)

It looks like there is no threads left in the bad cylinder. Hard to tell with the image out of focus. Did you inspect anything else like your timing belt? Does the engine turn over smoothly by hand? It sounds like you need a new timing belt and a new/rebuilt head.

mre2000

Thanks. Actually the motor is fine, turns over and still runs but obviously with no compression in that one cylinder, Just trying to see if there are other opinions before I pull the head. The bottom photo actually shows threads between the two rings (near the top of the inside ring)...I thought the plug disintegrated and left the threads in the socket but the bad plug still had its threads attached. It also seems that a good plug is too large to fit now, which makes little sense to me.

Lexus2000 - exactly my question...BUT WHAT? Thanks for trying

fortitude

here is a video on repairing stripped out spark plug with head still on

mre2000

great source, thanks! I Havent used a helicoil in a long time... hadn't even considered it for a spark plug. Might give it a shot since theres not much to lose. Thanks again