Off Topic: Unseize spark plugs

[nicky4tl]

Hi all,
Apologies for a totally off topic post but Ive found good advise here before. This isnt about a renault but instead my everyday car, a boring but faithful mazda 323. The spark plugs are seized in and now theres £300 of work to be done on the suspension, CV joints etc. Im hesitant to spend a penny as she drinks petrol lately and the mechanic says he cant get the spark plugs out. Before i send it to the scrapper does anyone have any tips on getting seized spark plugs out?
Thanks
Nicky

 

[malcolm]

Presumably the cylinder head is aluminium? The big trick is not to try to remove them when the engine is warm. Makes a lot of difference. Could try something like paraffin in there for a bit to loosen it off.

 

[nicky4tl]

Thanks clementine,
yep aluminium. Mechanic said he'd try again when the engine is really warm. After a lot of googling Im thinking the opposite as you suggest. Ive ordered kroil from midwayuk which is supposed to be a good penetrating oil. Figure I'll soak them for a week and then try heating the head with something (an iron? a blow torch?) while using a very cold (from freezer) socket on the plug. And if that all fails it looks like antoinette the renault 4 might be coming out of retirement a little earlier than anticipated this summer.

 

[timinder]

I'd have thought warm was the way to go - the head should expand more than the plugs and therefore loosen them very slightly. If you have a big enough oven and a tolerant other-half (or she/he is out!), try putting the head in there at around 90-100C for an hour or so to get a decent heat soak and then try removing the plugs. I wouldn't apply localised heating (blow torch etc.) as this would risk warping the head.

Another trick to try is to actually try to tighten the plugs (or any seized bolt) a fraction, as this can sometimes break the bond between the parts, allowing you to undo them.

 

[Greeney in France]

I still swear by coca cola it totally freed my seized hinge overnight infact.
I always wipe a little copper grease on the threads before I put them in now since in the 1990s I broke a plug trying to get it out and it cost me a head rebuild because of it