So yesterday the plug in the middle on the driver side (#4?) blew out. That plug has been in there 2+ years. I put a new one in and it drove fine for day. Today it blew out again and the threads won't catch on a new one. I bought a tap, covered it in grease and ran it through a couple times and it bites the threads but the spark plug still doesn't bite. I think I can feel the spark plug threads drag along the threads in the head so I'm pretty sure I'm ****ed.

Has anyone done a helicoil at home? It doesn't seem to be the most complicated thing in the whole world. I want to give it a shot.

Helicoil is pretty simple, I'd be concerned that metal shavings got inside your engine as well.

Not on a 4runner but on a Honda Civic. It held for some time but after 20,000 miles it went. In reflection, my brother and I should have just bought a used head and crossed our fingers. I didn't use high temp rtv, which probably killed it for us:
https://www.youtube.com/watch?v=1BTTur7Fk6k

Make sure you have it correctly started each time until you break through and most of the shavings are gone.

Timecert. One and done.

X2 on timesert. I had to do it. Bought kit from Amazon. Research I did, it's perfered over helicoil. Just rig up a long tip on an air compressor to blow out the aluminum shavings from the head. I did mine last year. No issues.

Sent from my SM-G920I using Tapatalk

This is the kit I bought. Had very complete instructions as well.

Sent from my SM-G920I using Tapatalk

Use a Time-sert. Helicoil isn't an appropriate solution for this problem. Do not use an air compressor to clean out the shavings, use a shop vac so you don't blow junk into the cylinder.

**** me dude, $200? Jesus christ... Worth it I suppose

What does this mean?

Yes $200 is too much. I did this on mine a year ago, 20K miles no problems. Air is fine for blowing it out, a shop vac isn't strong enough to get down in there and remove everything. I used WD40 after I was done, and it smoked a while. This is what I used.

https://www.summitracing.com/parts/l...FVCCfgodD18LfQ

Blow out is a major issue on some vehicles. Its recommended when doing any spark plug job to blow out the spark plug holes before removing any plugs so debris does not blow the plug out. But in your situation it was most likely fatigued aluminum threads from being over tq'ed during replacement of plugs and or not using an anti seize.

Like stated above you can use a heli coil. I always like to try and put that pistion at top dead center so less space for debris to fall and not as tough to blow out.

On a side not I have seen some Mitsubishi heads have heli coils all over. Few in the spark plug holes, few in the valve cover holes and many in the exhaust manifold holes. They are held up pretty good other than the exhaust manifold ones because they were under very high heat with turbos pushing 30+psi and that manifold is heavy as shit with a big turbo hanging off of it.

GOOD LUCK!!

Just as a note, Continental aircraft engines in years past came from the factory with helicoils in the spark plug holes. Not particularly high compression ratios or cylinder pressures, either. I think it was just a way to improve reliability in the aluminum heads.

agree put piston at top, I used the leslie kit listed above and did this on a bmw 4 cylinder car. I used a shop vac with a small hose on it that fit into the cylinder to suck out the crap

I ordered the time-cert. I can't find a bad review anywhere and I need to get this turd on the road by Monday morning. Or get my 240sx road-worthy....

take your time, and dip the tap into grease each time. remove and clean the shavings often. that should prevent most of the chips from getting into the cylinder. the tiny ones that do(if any) get it will either be burned up, or ejected out the exhaust.

I did this on my 22RE about 10 years ago. it was my daily driver up until 3 years ago. its been fine ever since.

i used this. o'reilly's less than 30 bucks