Can anyone explain how to change the spark plugs on a 1997 Millenia with the 2.5 engine. I need to know what type of plugs should be used. Which manufacturer has plugs that are good for the car. Should they be platiinum or not?. Are any special tools needed other than a ratchet set with a standard spark plug socket?

 

Always stick with OEM plugs, if Mazda recommends platinum the use that, if they say to use a NGK use that, engines are designed for a specific plug these days (look at the Trition plug) and usually run WORSE on something different. Don't believe the hype that the super expensive iridium tipped, plutonium core with a uranium shell will give you 50% fuel economy and 75% more power (all exagerated ) at BEST you might break even with the money you will save in fuel compared to the cost of the plugs IF they perform better. Alot of engineering goes into plug design and placement these days, some engines even need the electrode facing a certain way or it wont run right.

As for changing them dont do it on a warm engine if the head is aluminum, you have a much higher chance of stripping the plug hole out if you do. Are the plugs original? How many miles on the engine? These are very important questions since if the are original the chances of them also being seized in the head and ripping threads out is higher.

 

Thanks, I looked in the owners manual and they have recommended plugs listed. I'll plan to use the NGK s that they show.


The car has 93K. I think the plugs were changed 4-5 years ago. Do I need any special tools?. Can I just pull the boots by hand and use the socket wrench??

 

You shouldnt need any special tools that I know of, worst case you might need a plug wire remover if they are stuck onto the plugs. If the plugs do not turn out easy squirt a LITTLE PB Blaster into the hole and let it soak over night and try in the morning, doesnt hurt to blow out the plug holes before you do this too keep it all clean.