sparkplug keeps coming loose/unscrewed in the head

[subarulover1]

my 90 legacy wgn has a bad o2 cencer and censer wire also and a bad head that doesnt seem to want to tighten a sparkplug in tightly without keeping the plug in the head!?? am i looking to pull the head off and rethread the plug hole!?? and where could i find a o2 cencer wire and censer as a whole for less then 65 dollars close by or mail order companys also???? any sugestions id really appreciate thanks again lovers of the subarus!??

dave cornwell/subarulover1!

[Wayne Boncyk]

Well, if you can't keep a plug tightly threaded in, then you probably have a stripped out head -- bad news, since re-tapping the hole isn't likely to fix it -- not enough metal left to allow tapping out to the same diameter, if you've stripped it so bad that the plug's just spinning in place. I'd pull a replacement head from a junkyard, and start over. It'll give you some practice in proper torquing of head bolts -- then you ought to be ready to torque down that new plug without cross-threading or over-torquing it!

 

Unfortunately O2 sensors aren't exactly cheap - and $65 isn't a bad price for a replacement.

[idosubaru]

you can try a spark plug thread chaser, but like mentioned earlier there isn't likely enough metal left to work with. but it's free and something you can do yourself so it may be worth a shot.

 

if that doesn't work you can install an insert. that requires nothing but the inserts and some tools, no engine disassembling beyond removing the spark plug. there are kits to do this, if you don't feel comfortable doing it yourself...well, if you've never done it then it might be best to let a shop do it. there is chance of getting debris in the cyilnder, so this isn't the best place to start if you're not familiar with the process. a shop will charge $75 - $100 to do this. ask about the kits in an autoparts store and read the directions on the back to see if you want to try it yourself, or talk to the guys at the parts store, they may be able to show you the tool and how to do it.

 

good luck and have fun.

 

price the O2 sensors at an auto parts store and get the Universal type, not the direct fit type. the universal type requires removing the old O2 sensor and cutting off the electrical connector on it (you're throwing it away anyway!). then just connect the wiring harness to the new universal O2 sensor which will just have one loose wire on it. these can be had for older subaru's (like EA82 and ER27's) for 19.99. the direct fit O2 sensors are exactly the same as the one i just mentioned, but come with the wiring connector already attached. but for $40 savings you get the same thing and it only requires attaching one wire. very simple. if you can remove the spark plug, you can splice on the connector! as a side note - the car will run fine without the O2 sensor in case you're worried about jacking it up. but it's so easy i can't imagine any glitches.

 

good luck and have fun.

[Strakes]

If there isn't enough metal to work with, I second the spark plug thread insert suggestion. It works well.