Can anyway explain to me why my spark plugs keep backing themselves out?
This is twice now I've had to pull the coils off and tighten them down with no explained reason why
01-27-2013 05:34 PM
Please explain what your problem is.
01-27-2013 05:56 PM
They keep on backing themselves out for some reason and yes I tighten them down this would be twice that they have loosened themselves up
01-27-2013 05:56 PM
The threads are loose. This is a common problem with older cars- especially high mileage where plugs have been changed frequently.
Do you use anti-seize?
01-27-2013 06:24 PM
01-27-2013 06:59 PM
I'm not sure if that has something to do with it or not, but when spark plugs keep backing out- the problem is that the threads are too loose, or you're not tightening the plugs down enough. I'm assuming it's not the second one since you probably increased torque since the plugs loosened.
Get you some nickel anti-seize, the last time I looked here it was $7 for a big grey container of it that you'll get years of use out of. It also comes in little one time use packets for $1, but I see those as a waste. It's much better to have anti-seize laying around- it's very handy. I put some on where my axles fit into the hub so those won't seize up like the factory parts did. There are some places where using it might not be the wisest thing- like pinch bolts. But spark plugs in aluminum heads is a definite must-have.
It's messy. Just use a little on the top threads, and tighten down to 20-25 ft-lbs carefully. If you have been tightening to 20, and that wasn't working, you shouldn't cause any damage by going up to 25- now 45 might be a big deal, so don't go too far on your own.
01-27-2013 07:06 PM
OH, something I didn't think about, may be part of a problem in your car or not. On older cars crud would build up around the spark plug on high mileage heads. When you remove a plug, and then put another plug back in- the crud would get between the new plug and block screwing up your torque. I used to have to take a 1/2 extension, wrap a shop towel around it, and shove it in the spark plug socket and twist it around until I cleaned all the crud out from around the plug socket.
I don't know if that's your problem, but it might not hurt to either try cleaning, or shine a flashlight around in there to see if you have crud buildup.
01-27-2013 07:30 PM
I agree with whynot. A nice little tip is to make sure they will stay tight is snug them in when the head is warm. As the head cools it will clench on the threads, and hold them in nicely. The threads on your head might be loose which is common on higher mileage cars.
01-27-2013 08:35 PM
I thought that anti sieze was only to prevent them from freezing into the head?
01-27-2013 08:36 PM
She's got 83100 on the clock I can usually tell when they've come loose because my cylinder head temp sensor grommet pops off and won't stay on