Completely round spark plug. Why? How can I get it out? Topic is solved

myzomela · Post by **myzomela** » 29 Jul 2022, 04:46

2005 XC70, 186000km

I bought the car about 20000km ago, and went to swap the spark plugs for the first time. Nos.1, 2, 3 and 5 were routine. But No.4 is completely round, and I can't get a socket on it. I don't mean the flats are damaged and rounded - it looks like there never were any! Just a dark metal ring. Never seen anything like it.

Any ideas out there why there's such a spark plug? And how to get it out?

Thanks

Post by **abscate** » 29 Jul 2022, 06:39

You will need a extractor with fluted edges like those made by Irwin or others. That should work.

If not, the head will have to come off, ugh.

Post by **erikv11** » 29 Jul 2022, 08:16

Let's see a pic when (fingers crossed)! you get it out. Must actually be stripped right?

Post by **firstv70volvo** » 29 Jul 2022, 09:18

I don't think you have as bad of a problem as a rounded off spark plug. I used Photoshop to lighten your photo and it looks like the rubber spark plug boot broke off and is still in the spark plug hole. If you dig this out you should be able to get your socket on the plug.

Post by **abscate** » 29 Jul 2022, 09:48

firstv70volvo wrote: 29 Jul 2022, 09:18 I don't think you have as bad of a problem as a rounded off spark plug. I used Photoshop to lighten your photo and it looks like the rubber spark plug boot broke off and is still in the spark plug hole. If you dig this out you should be able to get your socket on the plug.

rounded spark plug.jpg

Nice work firstv70volvo!!!

Post by **cn90** » 29 Jul 2022, 19:57

This only happens in Down Under lol...

myzomela · Post by **myzomela** » 30 Jul 2022, 16:19

firstv70volvo wrote: 29 Jul 2022, 09:18 I don't think you have as bad of a problem as a rounded off spark plug. I used Photoshop to lighten your photo and it looks like the rubber spark plug boot broke off and is still in the spark plug hole. If you dig this out you should be able to get your socket on the plug.

Thanks - this was it! The rubber / plastic boot had got really hard and was stuck on very well. That tricked me into thinking it was part of the spark plug. But eventually i managed to work it loose and get it out. You'll see in this photo of the old plug that you could hardly design a better "cover" for the flats.

I've now got 5 new Bosch plugs in. I wonder if Bosch has found a new spark plug factory yet...

Post by **matthew1** » 30 Jul 2022, 16:39

Whew. I thought for a second the previous owner had installed one of those special round ÜRO spark plugs!

myzomela · Post by **myzomela** » 30 Jul 2022, 17:12

cn90 wrote: 29 Jul 2022, 19:57 This only happens in Down Under lol...

Yeah, must be 'cause we all drive around upside down

myzomela · Post by **myzomela** » 30 Jul 2022, 17:22

erikv11 wrote: 29 Jul 2022, 08:16 Let's see a pic when (fingers crossed)! you get it out. Must actually be stripped right?

There's a pic in my reply to firstv70volvo. Not stripped, thank goodness!