Spark plug removal ruin heads?

[Dave52]

Have a 95 Windstar at 173K miles with original plugs. Other maintenance has been kept up and the only other major trouble was head gaskets which Ford fixed for free 6 yrs ago. Repair shop told me they could do it but being they're so old they may have become "fused" to the head in which case the head plug threads could be stripped when the plugs are removed and may end up needing to buy new heads. The vehicle runs pretty good but starting to miss. I couldn't see spending big bucks for heads if they get damaged and am wondering about just driving it as is. Can the head plug threads really be destroyed? How easy are the back plugs to replace after the cowl is removed? The mechanic said he's seen a lot heads being damaged from removing old plugs.

Thanks
Dave

[12Ounce]

I believe that what damages spark plug threads in heads is one, or more, of four things:

1. Plugs being overtorqued when installed. Check the specs .... should be only 7 ft lbs or so ... that ain't much! If someone else installed them, you have no way of knowing.
2. Plugs being cross-threaded when installed. Don't use the wrench until you're sure the plug has started correctly and the threads are aligned.
3. Plugs being installed without anti-sieze applied on threads. Not totally necessary, but a good practice.
4. Plugs being removed when head is hot .... wait 'til its stone-cold!

Even at best, the plugs will tend to stick after several start-ups ... but I don't bellieve your plugs are any more "stuck" now than they would have been at 75 Kmiles. A shot of Rust-Buster or WD40, and some soak time, will help loosen up the outside of the plugs a little.

(This is advise from a rank amatuer ... ain't worth much!)

I like to remove the cowling ... but the rear ones are still a challenge.

[bychance ford]

Originally Posted by Dave52

Have a 95 Windstar at 173K miles with original plugs. Other maintenance has been kept up and the only other major trouble was head gaskets which Ford fixed for free 6 yrs ago. Repair shop told me they could do it but being they're so old they may have become "fused" to the head in which case the head plug threads could be stripped when the plugs are removed and may end up needing to buy new heads. The vehicle runs pretty good but starting to miss. I couldn't see spending big bucks for heads if they get damaged and am wondering about just driving it as is. Can the head plug threads really be destroyed? How easy are the back plugs to replace after the cowl is removed? The mechanic said he's seen a lot heads being damaged from removing old plugs.

Thanks
Dave

i would agree with 12ounce--i would let them soak with some rust remover.i have had the cowl off on my '96 a couple of times to do things,not to difficult.but i have had luck getting at the back plugs after running it up on ramps and laying under there.you just have to weave your arm past the rack and pinion and exhaust.if you are changing wires i would definitely remove the cowl.

[OldFaithful]

Talk about an amature. I was removing the plugs from my 2000 Windstar and the first one on the back side, I was tightening it instead of loosening it and the plug broke off. I sent it to a shop that does those kind of things and $75 later, I had my head back with a helicoil replacement for that plug and the head was trued up for installation. No new head was necessary. My NAPA parts man sent it to a shop that he knew did good work.

The same shop did another head when a valve spring broke. No valve lapping was necessary that time nor any truing up.

Good luck.

Jim

[dougand3]

The best rust beater I've found is PBlaster or PB blaster...yellow and white can at auto stores or even wally world. I'd coat all around the plug good and let sit for 6 - 24 hrs. I'm not so sure it's real easy to damage plug threads....maybe if you're off axis or bend the socket/extension while forcing. A great tool is a dedicated spark plug socket/extension...5/8" socket and long swiveling extension in one piece unit. I changed the back ones with windstar on ramps and laying on pillows, working upward and blind...not fun. next time, i'll pull the 2 cowls.

[LeSabre97mint]

Dave

172,000 on the orginal plugs! That's a lot of miles! I bet the gap is almost double of what it should be that is if there is any thing left of the electrodes. The best way I found to replace the rear plugs is like the other posters said is from the bottom with the van on ramps.

While you're at it, I would replace the wires too. I would be willing to bet they are getting brittle.

This is the

Regards

Dan

[ponchonutty]

Unless they are aluminum heads I bet you should be fine. Again, if they plug is stuck, there are ways (as mentioned) to fix or get around the problem.

[DRW1000]

Replacing the plugs and wires is probably worth the risk. As mentioned by many soak for as long as possible. Try the front three first. Heli-coils can often be installed without removing the heads if the spark plugs are easily accessable - although for a "proper job" the head should be removed. Judge how easily they come out before trying the backs.