Advice needed! Cylinder 3 spark plug hole dethreaded

[JennyandDex]

Advice needed for my Honda Jazz.

Posting for advice! It was recommended I try this channel to see if anyone else has a similar experience and how they tackled it.

I have a 2011 Honda Jazz which I purchased about a year and a half ago, incomplete service history. Now has 75,000 miles on the clock.

Has run great since purchase aside from some very minor issues, had a major service done when I first purchased it and another service done 6 months ago.

On 31st of Jan I noticed the engine was vibrating more that usual when the car was stationary with the engine running.
The following day I got a flashing amber check engine light that came on 2-3 minutes after starting the car and setting off.

I called out my AA breakdown cover to assess, who found that my spark plug in cylinder 3 had come loose and popped out while the engineer was doing diagnostics. Upon further investigation he found that the cylinder had dethreaded causing the spark plug to come loose and misfire.

As this was a bigger job, he recommended I get my car to a local garage for the work to be completed. I drove it slowly 5 miles down the road to the garage with breakdown van following close behind just in case.

My garage have now been sitting on this for almost two weeks while they investigate and look for a solution (they’ve clearly not dealt with this issue before). Last Friday they called me with a proposed solution to remove the cylinder head to get to the spark plug hole to rethread with a helicoil kit. But said that with cost of parts and labour I’d be looking at between £1000 - £1500 and encouraged me to consider scrapping the car due to the cost being very high compared to the value of the vehicle. They said that due to the depth of the spark plug hole, they’d be unable to do it in situ without taking the car apart.

Naturally I’m very reluctant to do this, I can’t afford another car right now and have been trying to do some research on alternative solutions. I’m not car savvy myself so doing this myself is completely out of the question, but I’ve been trying to at least educate myself on the problem.

I eventually discovered a mobile thread repair specialist mechanic that is local-ish to me, who has agreed to take on the job. He has quoted me for a helicoil repair in situ without removing the engine or cylinder head.

My current garage has gotten on board with this plan, but have told me that due to the location of cylinder 3, they will need to remove the intake manifold from my engine for the mechanic to access for the work.
The mobile mechanic tells me this is not necessary but is due to come work on the car on Friday.

Long story short I would appreciate any feedback from others if they’ve experienced this issue previously and how others have solved it. Am I being taken for a ride by my current garage here charging me for unnecessary work?
I appreciate this is a bit of a niche job, but from my research looks like it’s been heard of on this generation of Honda Jazz.

Thanks

[Kuruuvi]

Deleted

[Keekster71]

A helicoil is the correct solution for the problem.  If someone can do it in situ then that is definitely the way forward.  As for the intake manifold I'm a little puzzled by this.  Its not in the way when removing the spark plug so I'm not convinced it needs to be removed, but I guess it depends on the size and shape of the helicoil tool, although a quick google shows they are not chunky.  However, its not a big job to remove the intake manifold, so if its necessary to remove it then fair enough.

[Lord Voltermore]

Good workshop  practice probably is to remove the cylinder head for helicoiling or recutting the thread .
 This ensures no metal shavings and other debris drop into the combustion chamber during the process.   

But as you say this is quite a big job. In the past a dodge/bodge sometimes used on older cars  was to poke a piece of rag, heavily coated in grease  ,through the plug hole and into the combustion chamber.  With luck the grease captured  most, if not all , of any debris that fell in.   The rag was then carefully extracted ,bringing the  debris with it.   But I dont Know  if the Jazz  engine does have access problems that might prevent using thread repair tools in situ, or hamper successful insertion and removal of a greasy rag.   

The other problem is that a professional garage /mechanic may not be willing to do this bodge, which may not be 100% successful .It can leave  them vulnerable to criticism or liability  if anything goes wrong.   And you might not want to risk it yourself.   

[HertsHonda]

If the offending plug is is a loose fit i.e.has to be rotated to go into the head ~ then as a VERY temporary measure ~ make 2 / 3 fine saw cuts in the thread of an old correct sized Honda spark plug.
Thus forming a thread cutting Tap. Then recut the thread in the "stripped" plug hole. Personally I would not trust the bodge for many miles! A loose spark plug will be like a bullet! Helicoil is best!

@Lord Voltermore says
"Good workshop  practice probably is to remove the cylinder head for helicoiling or recutting the thread .  This ensures no metal shavings and other debris drop into the combustion chamber during the process."
I agree, keep the swarf out of the cylinder.

Maybe @JennyandDex has the tools/expertise/space/time to remove and replace the cylinder head after a local workshop/garage has fitted a helicoil?
   

[Kuruuvi]

The other option maybe to swap it with lower mileage engine as it will serve you for many years even if the cost is slightly higher now. You could get a low mileage engine for about £200.

[pebbles]

There are a couple of YouTube videos showing what's involved in sorting a stripped out plug hole thread on the Jazz , or Fit as it's called in the States.

Apparently it's a common problem on around 2010 models especially in the States due to the higher mileages.

Also I think the Time-cert is more common in the States than a Helicoil insert.

It's a bit of a mare job that's for sure , but doable

[take5]

enjoyed the video - very informative from what appears to be a very decent mechanic.

[Keekster71]

Great video.  It looks like the cause of that problem was plugs that had not been correctly torqued when replaced.  Given the long service schedule for these plugs, its very important they are tightened correctly, because they wont get checked again for years.  And a loose plug will eventually get blown out and take the threads with it.

[GBH]

I can't be the only one followng this and wondering where the OP has gone and what finally happened?

Found some of the posted videos really useful in as much as it showed how to reach the spark plugs in order to change them during a service.

The only time I have had a stripped spark plug thread was many years ago on a Honda N600 where one of the plugs blew out and hit the underside of the bonnet! Repair was a simple job because the engine was basically a twin cylinder, air cooled motorcycle engine with loads of room for access under the bonnet once the air ducting was removed. As it turned out the piston rings had also broken up (ironic because Honda's first product was piston rings for Toyota) so I removed the pistons and had a machine shop supply new rings and machine the ring grooves to suit as ring sets were not readily available.