Spark plug thread melted, ig. coil melted/burnt

[renatog]

Hi y'all, first post here. I guess I should've been here a while ago since I care a lot about my car and try to understand and do most fixes on my own. But this time I really got it bad. Here's a pic of my troubles:


I started noticing the misfiring Saturday night, but didn't understand what was happening. Come Sunday it got worse and worse. Monday I drove to work and dropped it off at the mech (Aamco) and here's the result. This just came out of nowhere, it's not like I replaced the spark plugs yesterday or recently. The last time they were replaced was at least 3 years ago. So now they're telling me they need to remove the head since they've already tried putting another spark plug in there and the thread in the head is not holding it down. Has anyone gone through this before? What might cause something like this to happen?
FML..

[fenixus]

jesus ... what car do you have ? what wires and spark plugs have you been using ? it looks horrible ...

[renatog]

It's all OEM except for the spark plugs, not sure what brand they are.

[kenny1773]

I have seen Bosh Platinum plugs do that in both Toyota and Honda engines. I will never use Bosh plugs again. Stick with NGK if you can, Denso as a second. I am not technically inclined enough to know what the underlying problem is with some plugs or to be able to explain it.

[gdanaher]

Check the plugs you have in the engine. Maybe the wrong heat range. As for stripping threads, this is most unusual unless they weren't installed correctly. I've seen plugs actually unscrew themselves. The mechanic should put some Helicoils in there without pulling the head.

[renatog]

I just checked out the Helicoil inserts, cool stuff! I'm going to recommend this to my mechanic.
Thanks

[gdanaher]

If your mechanic had not already thought of this and told you about it, then you need a different mechanic. Helicoils have been around for 75 years.

[89molavi]

I would just mention that with this problem you are better off towing the car to a decent mechanic. AAMCO is not even good for transmission work, forget about me letting them touch the cylinder head in my car. As eluded if they don't know about helicoils, that would be a hint. Where were the plugs changed the previous time? Seems they might not have done a good job. What year and how many miles on the car?

[JohnGD]

What plugs did you use?

I would recommend NGK wires and NGK Iridium-IX or Laser-Iridium plugs.

http://www.ngksparkplugs.com/part_fi...t.asp?mode=nml

[renatog]

Originally Posted by 89molavi

I would just mention that with this problem you are better off towing the car to a decent mechanic. AAMCO is not even good for transmission work, forget about me letting them touch the cylinder head in my car. As eluded if they don't know about helicoils, that would be a hint. Where were the plugs changed the previous time? Seems they might not have done a good job. What year and how many miles on the car?

2002 Camry 135K.
I changed the plugs last, that was 3 years ago. I don't remember what brand I used.

[PRINCESS PEACH]

OEM is Denso or NGK. use the former or the latter.

[njerald]

Originally Posted by renatog

2002 Camry 135K.
I changed the plugs last, that was 3 years ago. I don't remember what brand I used.

Look at the plug that came out............

[ben805]

unless the plug is faulty, otherwise it looks like that plug either wasn't install properly or somehow backed itself up overtime, allowing extreme heat to escape from the combustion chamber and melted the plug/thread and socket...

[JohnGD]

OP mentioned it was cross-threaded. So I think you're right, the plug didn't seat properly and combustion gas escaped to burn the plug and boot.

Originally Posted by ben805

unless the plug is faulty, otherwise it looks like that plug either wasn't install properly or somehow backed itself up overtime, allowing extreme heat to escape from the combustion chamber and melted the plug/thread and socket...

[89molavi]

I will go with a bad install/cross thread. A different brand plug might cause some problems, usually minor misfire and such. But this is a different story.