Rusty spark plug... what can i do?? - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

tup · 06-21-2006, 15:20

went to replace my plugs and couldn't get the last one out (no.6? closest to firewall)? ended up piling crc down the plug and undoing then doing up again until it finally broke free. totally covered in rust about 5 mls up from the bottom of the plug and now i have a slightly cross threaded spark plug chamber. (new plug went in ok though). pulled out plug two week later and already rust starting to build up again and plug was already rounding off at point... what could this possibly be??? car runs beaut usually.. doesn't miss or fart around .. it's on lpg whether that makes a difference?
thanks again

conan · 06-21-2006, 15:24

Thinking head gasket maybe, with water in chamber...

Aussiblue · 06-22-2006, 04:00

Water in the cylinder results in clean shiny plugs not rusty ones. Are you sure it's not MMT (Methycyclopentadienyl Maganese Tricarbonyl) that gives a rusty appearance on the insulator and side electrode. See http://www.classictruckshop.com/club...park/plugs.htm or http://www.nightrider.com/biketech/spkplghnbook.htm#Redor http://www.ngksparkplugs.com/techinf...q/faqread2.asp

tup · 06-24-2006, 01:24

pretty sure it isn't that ausieblue.. as it is the whole thread rusted out.. not the actual electrode etc....?? relief about the head gasket though.. :) even though that is probably due to happen soon with the mileage.

tup · 06-24-2006, 01:29

just had a big read on MMT and it wouldn't apply if i'm using LPG would it?? when i went to get a new plug the parts guy said i've been running the wrong plugs and gave me the right ones for lpg.. maybe that was the problem?? will check them again in a fortnight. thanks heaps guys

jas24zzk · 06-25-2006, 06:59

G'day,
aluminium head....hard to generate rust between it and the plug.....

Makes me ponder if the thread hasn't previously been damaged, and a helicoil has been used to repair it....most likely done in car.

Cheers
Jas

tup · 06-25-2006, 15:17

that's clever thinking jas.thanks for that. would i not be able to see the helicoil if there is one? I'll have to get that thread redone.. as it is going to be an ongoing problem by the looks. Had a squizz at the manual and it advised putting anticorrosion grease on the ends of the plugs when changing.. maybe it is a problem with the EAs? if it weren't for the lpg on this, i'd be getting an update.... a few things are starting to pack up.. but fuel prices are too awful here at the moment..

jas24zzk · 06-26-2006, 06:03

G'day,
it was merely an idea...steel on steel creates rust.
Yes you will be able to tell if it has had a helicoil....simply compare the plug hole to another...look for differences...you should be able to see the helicoil

Cheers
Jas

351cid · 06-30-2006, 05:32

on my old XF ute i had a rusty number 6 plug and it was caused by the alloy head was eaten out between the water jacket and the cylinder, making it leak past the head gasket.
had to get the head welded up , fixed the problem and cost about $250 with a valve grind .
it would miss a bit when it was cold then be fine,

creature3 · 07-06-2006, 04:54

I have a "slightly" blown head gasket, and also enjoy a "rusty" plug, but it's never hard to get out