So I pulled the plugs out of my girlfriend's 2005 Corolla over the weekend and noticed that there was rust present on the spark plug threads. Something else I noticed was that they seemed to be torqued down very tightly, requiring quite a bit of force to remove. I'm guessing this is because of the lessened amount of space between the threads due to the rust buildup. Has anyone seen or heard of this before? I know this isn't an S2000, but I figured I'd ask you guys first. Thanks

 

well rust could occur from steel threads, and auto companies pretty much put them in dry. So without any attention to them over a number of years and condensation occuring due to heat and cool periods they could rust. They come out stiff and squeaky as they were not lubed on installation, they are very dry. Reinstall new plugs with anti-sieze, take them out and inspect them once every 2 years, replace as needed, always lube them on install and try to do it when the head is cool.

 

Good point. The plugs themselves should be the stock ones as I don't think she's ever had them replaced and she's had the car since new. The ones I pulled out however were NGK Iridiums, which surprised me a bit as my S2000 had double platinums in as stock for the same 2005 model year.

 

Plug = steel, head = aluminum,
galvanic corrosion ftl!

 

your 05 should have come with iridiums

ike showing off your corrosion knowledge! lol

 

^haha hells yeah useful things i suppose...

 

toyota uses ngk iridiums in all their 1zz and 2zz engines... those are stock. and they do get seized up pretty well in their, i used to have a 2zz celica and my motehr currently has a 1zz corolla and both engines had plugs that seemed to take an excessive amount of force to get out.

(FYI if you didnt know, 1zz engine is a 1.8 VVT-i and 2zz is a 1.8 VVTL-i )

 

Cool thanks for the info. So I'm guessing my S2K plugs were replaced by the previous owner at some point if they weren't iridium?

 

no s2000 plugs are plats. yeah the dissimilar metals will cause corrosion, good reason to use anti sieze.

 

i recomend a little neverseive at the brgining of the threads,i use the loctite never seize stick