Seriously rusted plugs
 

I have a 1968 Mustang that I recently purchased. It runs beautiful, but the plugs are rusted into place. What is the method to remove these seriously rusted spark plugs.

Re: Seriously rusted plugs
 

Heat - Gently put a torch on the plug base and it should open up and twist out. Be cautious about putting too much muscle on the loosening process - if you break the plug off at the base you are going to the machine shop...

Re: Seriously rusted plugs
 

Thank you for your advice. I will give it a shot this weekend. I waited 15 years to buy this car, and I just want to make sure I do it right.

Re: Seriously rusted plugs
 

Sometimes it better to heat them up, then quench them quickly with water. Do this a few times, them blow all the water away from around the plugs with compressed air or shop vac. The expansion and contraction from heating and cooling will break the rust loose and they'll come right out. This works better than just heating them because if you heat them too much and put a wrench on them you may break them or round them off since the heat will soften the metal.

Re: Seriously rusted plugs
 

The problem with heating the plugs is that the heat will cause the plug base to expand and be tighter in the threaded hole.

I would, and have many times, squirt a mixture of ATF and spirts [kerosene, etc] around each rusted plug. Do it for several days. If you want use PB Blaster instead.

Let it soak and keep reapplying it. They should work out. Loosen a little, then turn back in. Back and forth, use plenty of PB. Patience is a plus here.

If you want hit the base of the plug with refridgerant. It will freeze the plug base, which will shrink it, and aid the removal.

Re: Seriously rusted plugs
 

If you want hit the base of the plug with refridgerant. It will freeze the plug base, which will shrink it, and aid the removal.[/QUOTE]

Doesn't freezing create expansion...Math days and Science are way past, but I always thought Heat shrunk and Cold expanded? Maybe with Metal it's different.

Re: Seriously rusted plugs
 

Heat does indeed cause expansion. What your thinking of is water, which unlike everything else in nature actually expands 10% when frozen. (I'm a Math major :)
I think the hot/cold treatment will get them loose, but I would try the penatrating oil attack first. (Having a torch under the hood is just not my thing).

Re: Seriously rusted plugs
 

When you heat metal it expands, cooling it will make it contract.

When you change a ring gear on a flywheel. First thing you do is heat the ring up with a torch and it will fall off. Then take the new one, heat it up and it will darn near fall on the flywheel.

Re: Seriously rusted plugs
 

Heat does cause expansion to both the plug and the head spark plug hole. What helps removal is the fact that the encircleing threads in the head expand more than the plug itself. That difference in the rate of expansion is what helps removal.

I would still try the penetrating oil first to try and get the plugs out. Be sure to get any grease off the engine before doing any heating though. You don't want a fire.

Rev

Re: Seriously rusted plugs
 

Wow - I think I now know more than I ever thought I would about the principal of heating and cooling. I am sure it will come in handy some day :)

Mystang68 - did you ever get the plugs out without lighting the car on fire?