threaded insert failure - how to remove?
 

Hi all,

I'm new to the forum and this is my first post. I have a 2001 Camry with a four cylinder. I'm not a professional mechanic, but I do work on my car/engine.

One of the spark plugs blew out of the engine recently. The threads in the head were stripped out, so I could not simply replace the plug.

I bought a heli-coil Sav-a-thread kit at the auto parts store and bored out the head, tapped new threads into the head, and installed the threaded insert with some red lock-tite on it. This was challenging because I had never done this before and the tools were not designed to work in the deep holes the plugs go into. With a little inginuity, I none-the-less got the insert in and secured it with the provided tools.

I let it sit 24 hours and it seemed to have worked perfectly. Car ran fine for about two months. Then it started missing and running rough. I looked under the hood and notice the plug wire was not secured to the plug so I pushed it back on and started the engine. The wire blew off again.

So, there is pressure from the cylinder leaking through the insert and blowing the wire off the plug. Arcing between the plug and wire is igniting the cylnder and the engine is loosing pressure in that cylinder, causing fuel to ignite in the spark plug shaft where the wire goes.

I tightened the plug back down, but it's not staying tight. I tried to remove it and the plug comes out but the insert stays put. I can tell the insert is loose and it is obviously not sealing.

So my question is this; how do I remove the insert so I can replace it with the same or a larger version?

I know some manufactures make over-sized insert kits to repair this exact problem, but I can't find a "removal" tool for the insert that is stuck in there...

Thanks for helping if you can!

Ryan D.

did you try a new spark plug in that problem cylinder

helicoil is stainless steel into aluminium
safe removal might be possible if head is removed and sent to a head reco shop
or
possibly aluminum weld over the leaking helicoil from the valve chamber side


this seller in Missouri wants US $375 for a good 5SFE head

Toyota 2.2 5SFE



if it was my engine
i would source a used or re-coed head
and not try to fix such a helicoil problem

....

Thanks DH!

I did replace the spark plug.

I had not considered replacing the head -- that is certainly a viable option and possibly the best way to resolve the issue. I will look into that! I appreciate the info.

I'd still like to know how to remove the insert if possible. Would a screw extractor work if I found the correct size? A plumber's nipple extractor? Any mechanics out there run across this before?

Thanks again!

Ryan D.

I found removal tool information

http://www.rugged-portable.com/helic...ipped-threads/

and
a helicoil thread removal tool

http://www.thorintl.com/HeliCoil-Arm...ng-Tools.shtml

Thanks again DH!

This tools is for the standard helicoil inserts that resemble little slinky toys -- they are much softer than the inserts I used (which also come from helicoil) I used these:

https://www.walmart.com/ip/Helicoil-...r-Kit/25514340

They are a much harder metal and I'm concerned this tool will not be able to "grab" them.

I was thinking a reverse thread/"easy out" type screw extractor of a very particular size might be the ticket?

Ryan D.

been doing more research on this

try an easy out . ..take your time

the trick is to get easy out to bite in to the helicoil only and extracting

without the threaded aluminum you made for that helicoil being stripped out as well

Operation successful -- not!
 

OK,

I found an easyout big enough to remove the old insert and rethreaded the spark plug hole and installed a new instert, this time with high-heat gasket material. Let it dry 24hrs.

Now the spark plug wire keeps blowing off the plug, causing the engine to run rough, with little power. I can put the wire back on the plug, start the engine and immediately watch it rise up. I drove it and the plug blew out of the motor again.

So, I'm not liking the "threaded insert" repair -- it worked temporarily. Now I'm guessing the head is bad -- either cracked or the spark plug hole is stripped again. Unless someone has a better idea, I'm gonna shop around for a used replacement head and a real mechanic to install it...

Thanks for all your help, dirty hands!

Ryan D.

Does the spark plug tighten down OK?

The gasket on the plug should seal off the spark plug hole.

Determine if the hole face is smooth to allow the gasket to seal.

Determine if the plug body is able to screw all the way into the hole to allow the gasket to seal.

It has happened spark plugs can fail allowing exhaust gas to escape up through the body.

Toyomoho,

Well the spark plug tightened down after I installed a new threaded insert. I don't have a torque wrench, but I was careful to snug it without over-cranking it. It was tight enough that the seal should have seated.

The truth is I don't know if the insert was flush with the head because I can't see well enough down the 6-8" tube that the spark plug goes down into before you can start to thread it in.

To determine the proper height to set the insert, I screwed the insert onto a plug and threaded that assembly into the head until it stopped. I then removed the plug, leaving the insert behind. I then used the tapered tool that came with the insert to tap the top edge of the insert till it spread open causing it to grip into the aluminum head.

It is possible that it could have unscrewed the insert a bit before the plug unscrewed. I just can't see down that hole... I wish I had one of those inspection camera to get down there and see, but I don't have one.

I could be the silicone gasket material bunched up at the top of the insert and dried there, but that should have let me tighten and seal the plug, right?

None of this would be hard to determine and answer if I could get a good look at the head/threads/insert.

I was unaware that a defective plug could let the pressure come through it, but wouldn't that make it less likely to get blown out? Good to know. That could explain the wire being blown off.

In any case, I appreciate the thoughts/questions/effort.

Ryan D.

There are inexpensive flashlights having a snake head that can be put down the hole to allow better light. Compare the threaded hole with an undamaged one.