Showing results for 
Search instead for 
Did you mean: 
Hagerty Employee

Things to know when changing your spark plugs | DIY | Hagerty Media

Keeping your car in peak running condition is a good idea for a multitude of reasons. A basic tune-up can expose critical information about parts of your engine that are otherwise difficult to inspect. Spark plugs are a critical part of any tune-up and a great entry-level DIY project.
Intermediate Driver

Nice video but I can’t believe that you would show “guessing” like that at setting the gap. I have a second feeler gauge set that I use for that. Just insert the correct gauge and press down till there is gentle push back. 100% right every time.

Number one rule: make sure that the engine is cool or cold, especially on an aluminum cylinder head. Use an air blow gun to clean the plug recess prior to removing the old plug. You may want to invest in a plug reach thread chaser because you never know when you might have to clean up those first three turns. Always use dielectric grease on the plug boots when reinstalling the wires. And that pretty blue anodized gap checker is only going to be accurate once. The act of sliding a plug across the measuring face will start removing the anodizing and then start removing aluminum. Likewise, the leaf type feeler gauges are great for setting valve lash, but can be a pain when trying to stack up thirty-five thousands worth of them. The steel coin-type gauge is a better bet, but you might want to verify its accuracy with a digital caliper and make a note of any variances. Check the gap of the old plugs after removal and note the change (if you were the one that installed them.) Consider going one or two ranges hotter on a somewhat tired engine; it might help avoid oil fouling. Ohm-check the plug (and coil) wires to ensure that there's not a weak one that isn't sending all of the current to the plugs. And finally, consider buying a flex-head extended handle ratchet that is used for spark plug duty ONLY, such as the SnapOn FNF100.

I still use anti-seize carefully like always on aluminum. Never ever had a problem, not taking any chances now, its insurance for me. Torque at the low side, again never a problem. Agree that probably many people don't apply it correctly and have a problem though.

You don't need the rubber, fingers work better at alignment, you cannot get enough leverage to cross thread. Been doing them for over 50 years now. You have to be especially careful on the OHC engines.