When to change spark plugs?
 

I don't know what plugs are in there now bought her like that. Performance is ok, milage could be better, i get about 550 KM on a tank of 91 premium. She starts very good in cold weather.

So if it aint broke, dont fix it ?

or

Put some NGK Platinums for good measure ? (what are the best plugs for the 4th gen ? performance and fuel economy wise?)

With gas prices they way they are, Id say put NGK plats in, throw a little anti sieze on the threads, and drive happy for atleast 30k (then check and replace if necessary)

They are easy to put in. Dont let people talk you into coppers, i tried em, they worked ok, but after 10k i took one out for a look, and it needed relacing, Plat is worth the extra few $$

Yeah i read that when i searched the org. I have no problem spending a little more on plats, right now they are 20% off at a local store. What exactly do spark plugs affect in an engine? (you mentioned gas prices, would new plugs burn less gas?)

do the ngk plats need to be gapped? (measured) because i believe on the coppers you do

I am right there with you andrei. I bought my car just over a month ago with 107K miles and I am faced with the issue of changing everything. I made sure the air filter was clean and i know that the oil and oil filers are new because the oil is relatively new <1000 miles. If it is still cold when it comes time for an oil change, ill bring it into get it changed and ask them to look at the fluids again...already had them checked when i bought the car...but I think that unless my car starts to run ****ty im not going to change the plugs.

I have only changed air filter, and know that oil and oil filter are on the newer side. Everything else has been left alone. Ive put on almost 1000 miles in the last month and everything has been running well so far...knock on wood.

They say that you dont need to gap their plugs, gap them anyways, cant hurt, only takes a few minutes and costs 99cents for a gapper.

Spark plugs effect alot, bad (dirty, old, poor quality) plugs will hurt (or destroy) gas mileage, can cause misfires, can cause rough starts, and so on, Good plugs keep your engine running healthy which has a domino effect on the rest of your engine (in a good way). One example, a old fouled (dirty) plug is in your car, it sparks, and the car runs, but gas mileage is hurt, as its unable to ignite the full fuel charge. So the computer compensates adding more gas, this is wasting gas, but what about that left over unburned fuel? some of it will go out through the exhaust, your cat will not like that, your oxygen sensors will not like that, and the atmosphere will not like that. Some of it will remain in the cylinders and sneak past the ring packs down onto the cylinder walls, and into the oil. Fuel is a horrible lubricant and your engine will wear much quicker. this is one possible scrnario. So yes, for my money (esspescially at 20% off) new plugs are worth it. If you want, pull one out and take some pics of it and we may be able to tell you something about its condition.

Also, just as a side note, my car, when i changed the plugs and put coppers in (the first time, im back to plats as i said) the drivers side, rear head, two plugs (middle and drivers side) were clearly older than the others, they are a tad harder to change, and some schumuck never changed them. Overall my plugs werent bad, but the car certaninly is running great on its new plats

I don't gap because every time I check a plug it's gapped just as it's supposed to be.

I use the OEM platinums and change them every 60k. Works for me.

Dave

i always gap because its only a matter of seconds to gap them.

plugs should be changed at 30k on average, platinums i think is 60k

reguardless of age, i would personally put in new plugs when i get a car, so i know for a fact that they are new isntead of playing a guessing game because honestly there is no real way to tell the diffrence between 15k and 100k if you have a good running car. I mean obviously you can tell a brand new one from an old one but thats about it. I've seen plugs off drag racers that swap out in between runs so its only a 1/4 mile and some are just plain out nasty looking and some are the clean.

with a buying a used car without maintence records. it is safe to change the simple stuff that costs you very little.

Wow thanks for the great responses guys, this is impressive stuff. Taking one out and checking it sounds like a good idea, i could wait for a break in the frigid weather and try that, but the 20% off sale may end this coming Thursday.

I think i will change the plugs because when I changed my air filter it was nasty, i don't think I have ever run an air filter until that condition in any of the cars I have ever owned. This tells me the previous owner was a cheap a$$ or had no clue about maintenance and didn't give a damn about the car. Well, I do so I will run and buy those NGK platinums tomorrow.

What's this gapping stuff? Should they not fit snug in there ?

no no no, gapping is the space between the electrode and the melt part. its on the spark plug themselves. there is a tool spark plug gapper its about 99 cents or so. most should be pre-gapped but when i got my coppers 5 out of the 6 where not.

http://www.ngkntk.co.uk/technicaltips/sparkpluggap.asp

andrei, just get the NGK plats and be done with it. If the air filter was that bad, then i'd say you should check the plugs (and change them). You also should consider changing the fuel filter if you haven't done so already! (it's pita to do, but well worth it!!)

never put coppers in. use NGK laser plats and do as kcryan said in the bold :werd2:

I have used NGK plats. NGK Iridium. Denso Iridium and NGK coppers. All worked fine. Why do you say, "Never use coppers"? explain...

coppers work just as well as the platinums. The only difference is the Coppers have half the life span than the Plats, besides that they perform the same.

What will the fuel filter improve ?

so far i have replaced:
PCV Valve
Air filter (paper)
engine oil & filter (castrol GTX)
tranny fluid flush and fill
put in STP fuel injector cleaner

with a cleaner fuel filter, fuel flow will be smoother, filter can clean better since it will be brand new.

its the same principals as changing your air filter.

Just for future reference, STP is not as good as say, gunmount regane, or Chevron Techron, but its not bad either

well, when i took mine out, the fuel that was left in there was brown in color (last time i checked, it's suppoed to be clear) All i can tell ya is that after changing it, i didn't have a vibrating gas pedal when i went WOT.

I changed mine on 4th gen at 80k miles. Plugs looked clean and no abnormal wear. Yes, I did change fuel filter at this time. An main belt (alternator/AC). Again just minor wear.

I was going on a 3k trip so I just did maintenance and check all bulbs etc.

You should get the radiator coolant checked out too. If the previous owner was a cheapo, the radiator likely needs to be flushed.

Surpirse Surprise !

Well, today i started pulling out my front 3 plugs, and guess what, i pull out NGK IRIDIUMS, haha what a find, they look in good condition, very little deposits, the tip looked brownish but clean. No oil at all on the plugs, they were super dry. No hassle getting them out as well came out very easy. So I left the Iridiums and refunded the Plats that I bought earlier in the day. I will just wait and replace them when i NEED to.

Iridiums seem to be the new craze. If you were boosting the hell out of that motor i would reccomend them, but in a normal application, if they get a little fuel on them (and they will) they become pretty much crap, giving about 40% of the spark they should. Anyways, if they are in good condition, keep them, but i would not use them in a NA application

There is nothing wrong with coppers, and platinums do not need to be replaced after only 30k.