[Gibbyman]

I was trying to get rid of a small misfire on acceleration in my 2008 Allure 3800 and started with plugs and wires. #5 came out and #’s 1& 3 broke off leaving threaded part in head. So with proper size twist drill and a gob of grease on it I drilled until taper where they tighten on was gone and fairly easy from there with ua standard screwdriver in it catching hook at end of plug. Worse part was #1 I had to remove cooling fans to get drill in there. So needless I haven’t done tha the rear ones ye because if they break I can try a right angle drill or pull the engine. Any tips greatly appreciate. Do while engine is hot? or lots of Thust penetrant??? Bf

 

[dezldave961]

That's an odd issue, sorry this is on your plate.

I'd lean towards the PB blaster option, and see if you can get them with no more than a 3/8 ratchet's level of effort (handle size helps limit leverage applied). Possibly try hot after that, if needed, but still cautious of effort.

Remove the various "junk" on the back of the engine to make it easier (engine cover bracket, alternator support brace, etc.), and pull the dog bone mounts to tug the engine forward so you can use the extra hole for the coilpack-side dogbone to be an inch forward. Comfort is key to concentrating more on the task at hand.

 

[davegibson579]

It’s not that I can’t get at the spark plugs it’s if any of the back ones break off I won’t be able to fit drill in between head and firewall to drill out if they break.

 

[dezldave961]

Sure, but it's kind of a necessary band-aid rip off at this point. The car needs old parts out to start making it run better, and you can also go for a 90deg angle drill to do that deed, if necessary (the additional space adds to what can fit back there for the work, and help you see the workspace).

I'll be interested in what your ultimate results are here. Obviously, utilize anti seize and maybe torque specs for your own benefit, since you're in charge of this work, now.

 

[davegibson579]

I’ll definitely remove the engine cover bracket and alternator mount support they are a real pain in the ARMS!!! Also will ditch the dog bones and pull engine forward thanks for opening my eyes I never thought about. The car was my sisters and very well taken care of routine oil changes and service car wash weekly in winter to remove the lovely tons of salt we get dumped on our roads that love to eat cars and truck. i do wonder about plugs and wires and looking thro her service records/invoices I didn’t find anything pertaining to sparkplugs. Also I had to scrape around them with a screwdriver to get socket on all the way. I know they aren’t original because they are NGK’s not AC Delco so who knows how long they’ve been in there!🧐🧐🥴🥴 thanks and I’ll keep you posted and accept any further advice/ ideas

 

[dezldave961]

Key to using the dogbone trick is:
A) be on a flat enough surface to rock car back and forth by pulling alternator/upper intake
B) don't have parking brake on until in forward position you want to keep (obvious, but can slip your mind as you're setting up)
C) using just the passenger dogbone, with front bolt just finger-tight, pull forward to place rear bolt thru this single hole (image below). This gets the engine about as far forward as necessary for anything you need.

 

[No N20]

I'd hit the plugs with some PB blaster and let it set, then run the car for 30 to 60 seconds to get some heat into the head. do this a few times before putting a wrench to it.

 

[Jim R]

CorrosionX...Years ago I had a plumbing fitting, brass on steel I think, that I could not get loose. I tried WD-40 and Liquid Wrench with no success. The joint was against the wall, so a torch would be a bad idea. I went to this local hardware store and the guy sold me CorrossionX in a spray can. I sprayed it on and waited the advised 20 minutes and I was able to get the fitting loose with modest effort. It was not that expensive decades ago. I just saw it on Amazon for nearly $20 for a 5 oz can. Since then I have always had a can for those tough threads. I did mention not using a torch. If your heads were on the bench, a propane torch would probably be my first choice, but under the hood with fuel rails and wiring and all, that would be very dangerous. Just a common sense reminder.

 

[Sortaslow]

And Kroil..one of the best products I have ever used