Guys, I have a 2003 F150 XLT super crew cab p/u..4.6 motor It has 74,000 miles on it with original plugs.. I'm thinking I will change the plugs in hopes of getting a little better mileage( between 10 and 12 now).. --- Is this motor one that has a problem with plugs breaking when being removed??? Any info will help... Thanks Mud

 

no those are the 04-08 5.4's

 

Just make sure not to overtighten when you put the new ones in. They'll strip out fairly easily. On the other hand if you don't get it tight enough you may end up with a blown plug.

 

I torqued one to 45ft pounds on accident. First one of the day and didn't realize my torque wrench wasn't working. No issue.

 

Nah. The head threads (5) withstand up to 100' lbs of torque. Although you would never do that, on purpose lol. Cross threading and NOT ENOUGH torque is why they shoot back out or become damaged.

 

I hate that, I finally broke down and got a good set of torque wrenches some time ago. I abused them back then as well lol.

45' lbs won't hurt the heads but it's very close to plug yield. Where the plug seal takes damage or the the porcelain cracks.

Actually, I think 45' lbs is standing torque yield for plug integrity. These take 28' lbs of course.

 

Not one of my best moments. I was like "wow it seems I'm putting a lot of torque on this baby". Took the wrench over to the vice and cranked on it. Apparently the clicky one's don't do very well with low torque or mine is worn out.

I never did check the plug for cracks, I probably should have. Loosened it up and tightened correctly with the needle torque wrench.

I did go over every plug a year later and they were all still tight @ 28ft pounds dry.

 

I like to torque mine to 336...

 

 

37.96 for me