Rear spark plug won't bite!

Technical Area Engine, Transmission, Exhaust etc
1

Hi,

I’m a new owner of a lovely 2010 NC with 61k on the clock. It was for sale in the classifieds here in fact, and has MeisterR suspension, the BBR Super 180 manifold and tune and a IL Motorsport exhaust.

I really couldn’t be happier, it’s such great fun to drive, and I’m relishing being back in a manual.

Anyway, I thought I’d change the spark plugs, since can see no record of it in the service history, and as I said, it’s at 61k.,It looked easy from the YouTube video I found so thought I’d take it on. And it was… to a point, and have had to give up for now since it’s got dark!

Removing the existing plugs was fine, although the back one had some cracked ceramic. That is obviously concerning so I rigged a hose onto my hoover with some tape and did suck one or two bits out. Pretty confident I got them, since had a couple of goes at it, but obviously not ideal…

Anyway, the front three plugs bit fine into the thread by turning them by hand for little amount, and could then torque up to 12nm without issue.

The last one, at the back, is proving to be an absolute nightmare! I’m wondering whether there is something wrong with the thread on the socket since I just cannot get it to bite in!

Not sure what to do. Has anyone else experienced similar?

Obviously the car is not driveable at the moment, so cannot really ask my local garage for help!

Any advice gratefully received!

Cheers,

Pacman

PS: I’m in Bath if anyone can recommend a local mobile specialist I guess.

2

Not something I have experienced but have seen similar issues often enough when I was working in a Volvo garage in the last millenium. I’d soak the plug with penetrating oil, Halfords stock several, for a day or so, then using a long handle ratchet, put at least a two foot length of pipe over your exisiting ratchet if you do not have a long ratchet, then gently ease the plug anticlockwise, if it moves just a gnats, turn the ratchet a gnats clockwise and then repeat anticlock wise and see if it will move a gnats more and so on aiming to turn the plug a little further with each anticlockwise repetion. Do not be tempted to try and remove the plug all in one go and you might just find you can save the thread. Good luck.

3

As I understand it he has all of the plugs out, he is having trouble locating the rear plug into the threads in the head.
:heart:

4

Damaged threads in the head maybe, you could try a tap just to clean up the start of the threads and not go too mad with it debris wise but its a bit of a risk and awkward too.

Will the old plug screw back in?

5

Yeah, I’m wondering whether the threads are damaged. Just exploring thread chasing tools. This Sealey ms003 looks promising perhaps (apart from it breaking for one user), but still researching: https://amzn.eu/d/0gCaC21y

I could try one of the old plugs, but not looking in the best shape. I guess could make it drivable again though… that’d mean the thread on the new plug is the problem which is the preferred way around I guess!

At the moment I have three new plugs in, and no plug at the back.

6

Try one one the plugs that you’ve fitted in the number 4 plug hole and the plug that you’ve not fitted in one of the other holes. This would confirm if the thread on the plug is OK or not.