Lazlo123

I've done a search, a couple of times using different key words and still can't find what i'm looking for... i want to change out the plugs in my 2000 dx... does anybody know of a website containing step by step instructions?

Thanks for your help!

Roddimus Prime

um, it's fairly easy. Do you have a ratchet and 10mm socket?

on the top of your valve cover is two black boxes held on by 4 10mm nuts. Take those off. Wiggle the coil pack off the plug and lay directly behind the cylinder it came off. Wiggle and remove the other two spark wires and do the same. Now with your spark plug socket and ratchet stick it down in that hole and unscrew the plugs. Take your properly gapped plugs add a dab of anti-seize paste onto the threads (being careful not to get any on the electrode) and screw them back in BY HAND. After you're sure all have threaded smoothly and you're not cross-threading, use your ratchet to snug them in the head. Reattach your wires/packs and press firmly to lock them onto the plug. Use the 10mm nuts to secure everything again and you're done.

Lazlo123

ratchet and sockets yes...

thanks for the reply and the instructions, i'll give it a go... i've changed plugs on an 84 grand wagoneer... but on this there just doesn't seem to be any obvious spark plug wires going to spark plugs... so i was lost...

thanks again

juddz

And, torque should be 25-30 Nm in an our Mazdas (aluminum cylinder head & a 14mm plug), in case you are curious. Or, if you don't have a torque wrench, you can tighten in to the correct torque by rotating the wrench 2/3 of a turn right after you feel the gasket begin to compress.

GNO

You definitely don't want to overtorque the spark plugs. The anti-sieze is a good suggestion.

Put a little dab of dielectric grease in the boot prior to reattaching the wire, as well. While dielectric grease is non-conductive, it will help seal the connection.

juddz

You don't want to under torque spark plugs. A plug torqued to say, 8 Nm has far reduced thermal performance, since a tight fit is necessary for proper heat transfer from the ceramic, through the metal shell, and to the water jacket. Over torqued plugs are less problematic, since the metal shells and threads are far stronger than 30 Nm. But, I wouldn't risk it. Either use a torque wrench, or follow the tightening angle procedure as noted above.

GNO

I agree, under torquing is definitely bad. I've had a spark plug work itself loose and shoot out. Other than becoming extremely loud, it wasn't a real problem.

I've heard that the threads on Aluminum heads are easily stripped, which is why I warned against over-torquing.

Roddimus Prime

yeah, I'd rather have poor thermal transfer than have to pull and repair my head.

Harbor freight sells 3/8" torque wrenches for about $6. May not last real long but I'd think of it moe like $6 insurance.

GNO

My torque wrenches from Northern Tools has lasted me over 10 years.

juddz

Having the correct spark plug heat range is critical to avoid destroying your engine. Not properly installing a plug (and thus diminishing heat transfer from the ceramic to the water jacket) is one way to change the ability to remove heat. Poor thermal transfer = overheated electrodes, oxidation on the ground wire, and a darned good chance of pre-ignition. This melts holes in pistons, burns valves, and basically destroys engines.

I wouldn't want damaged threads, either. But a finger tight plug is also a recipe for disaster.

GNO

LOL, no one ever said finger tight. Matty said screw them in by hand (to prevent cross-threading) and then snug them down with a ratchet.

Specture

do you have a link for that cheap torque wrench you mentioned rod?

Lazlo123

thanks everyone for the tips and advice. I'll definately have to look at whats out there for torque wrenches... i had no idea...

first, let me see if i understand where the plugs are. I think i know what black boxes and 4 bolts you are talking about are, but what are the coil packs? let me see if i can attach this picture...
the area in question is all the stuff just below the "16 valve" right.. ?

Roddimus Prime

oops, i assumed you had a 2.0L motor. Either way, The coil packs are what is being held on by those 4 screws. By uunscrewing those the pack will lift up and expose another plug underneath.

just make sure you put them back in the right order....the right wire to the right cylinder....Tape with numbers on it wouldn't hurt anything either.

AlexB2

Bump....

Sorry - a question to the ones in the know - how often ( mileage ) would you replace the spark plugs on the 2.0L motor ( 03 P5 )?

Thanks!