Spark Plug vacuum leak

[Timothy]

Update: I have talked to a machine/engine shop. For advice. He said most likely culprit is the cyclinder head is cracked. He also said that the threads on the plug should be more than enough to contain a pressure or vacuum leak.

Upon further inspection of my photos it appears there might be a crack, however to my untrained eye I am unable to verify. Also seems weird that there could be a crack on 3 out of 4 seats unless the previous owner went crazy on the spark plug torque.

Attacked is the photo of the possible crack. IMG_0607.jpg

[FestYboy]

Might be time to pull the head... Swap with a known good one, or have yours magnifluxed and repaired as needed.

[Timothy]

Might be time to pull the head... Swap with a known good one, or have yours magnifluxed and repaired as needed.

Thanks for the advice. I've been looking into the magniflux kits. Kind of pricey but I'll find one soon.

[Timothy]

I might have found a possible solution. If I used the product listed below I could thread the insert with locktite and then slam in some exhaust cement or job weld all the way around the fitting. The video gives a quick explanation of how the product works. The only problem is that Dorman says it will only work for a certain range of ford vehicles with 5.4L engines.

If the Festiva has the same 14mm thread size and same 19mm thread depth and same heat range of 7 why wouldn't it work? The only problem I see is that the plug boot might stick out a little long. Maybe the hex shape of the tool won't go down the spark plug well properly?

This way if the spark plug fails this setup will allow me to remove and replace the spark plug.

https://www.amazon.com/Dorman-42025-HELP-Cylinder-Repair/dp/B000TYVU1U

https://youtu.be/cE8EqpmePik

[FestYboy]

Nope! Nope nope nope nope nope.
That kit will put the plug tip in a really bad position.

If you want to put an insert in, get a real insert kit that uses a boring tap and lock that in place with whatever you want. That way the plug tip stays in the right position.

[Timothy]

Got it. Thanks for keeping me on the straight and narrow. But I really don't understand why it wouldn't work. The insert is the same depth as a spark plug. And when you insert the spark plug that it comes with it seats all the way to the bottom of the insert.

The spark plug they give you has threads much higher up than normal so the electrode seats at the bottom of the insert.

At $40 per insert this would be an expensive fix for all four plugs and replacing the head would make more sense. But I'm still curious why this doesn't work.

[Timothy]

Harbor Freight Torque Wrench
20% Off Printable Coupon

Do yourself a favor and get a Torque Wrench and try not to drop it.

Firebush357 I am proud to report I am the proud new owner of a torque wrench. TRhanks againfor the coupon. I saved $4.

[FestYboy]

Got it. Thanks for keeping me on the straight and narrow. But I really don't understand why it wouldn't work. The insert is the same depth as a spark plug. And when you insert the spark plug that it comes with it seats all the way to the bottom of the insert.

The spark plug they give you has threads much higher up than normal so the electrode seats at the bottom of the insert.

At $40 per insert this would be an expensive fix for all four plugs and replacing the head would make more sense. But I'm still curious why this doesn't work.

The plug is mentioned for the 5.4 Triton engine and the chamber and ignition circuit are totally different from a Festiva. Festivas aren't designed to run double platinum plugs. Also the kit is designed to bore a new hole in the head to insert the steel sleeve so that the plug collar doesn't sieze in the aluminum head. It also doesn't help that those plugs are junk.

[Timothy]

The plug is mentioned for the 5.4 Triton engine and the chamber and ignition circuit are totally different from a Festiva. Festivas aren't designed to run double platinum plugs. Also the kit is designed to bore a new hole in the head to insert the steel sleeve so that the plug collar doesn't sieze in the aluminum head. It also doesn't help that those plugs are junk.

Cool. Thanks for explaining that to me. I know my questions can be annoying but I love to understand the how's and whys. And now as a bonus I just learned what a double platinum spark plug is.

[Dragonhealer]

Timothy, I wish I had seen this back when....
Your first pic is perfectly clear, and your last is telling.
you are the victim of some badly installed thread repair inserts of the worst sort. Replace the head.

[Timothy]

Timothy, I wish I had seen this back when....
Your first pic is perfectly clear, and your last is telling.
you are the victim of some badly installed thread repair inserts of the worst sort. Replace the head.

Thanks for your help Dragonhealer. I appreciate your input. What were some of the indications that these are bad inserts. What did you notice? I'll make sure to keep an eye out for this when inspecting cars in the future. Just let me know what to look for. Thanks again for your help.

[Dragonhealer]

Perhaps just experience, did a lot of thread repairs in the military as well as 20 years at British Car service. Back in the day, there was a thin wall insert for sparkplug hole repair that was really crappy, and leaks were common around the insert. A modern sparkplug seal washer will seal almost anything but not that.