I have got NGK iridium spark plugs in my 2004 Mazda 6 that I put in 30k ago. Local car mechanic says they are worn out when he inspected them doing a regular service. I thought they were meant to be good for around 100K. ?
Having a look myself, the centre electrode still looks ok. Just that there is a bit of a light tan carbon buildup on them. What do others think?
And what happened to the spark plug cleaning machines garages used to have?
franc123,
Dec 17, 5:38pm
It isn't worn out, there would be far more wear on the earth electrode if they were, it shows there first before it does on the iridium tip. You've got a hell of a lot more than 'light carbon buildup' on there, that's considerable ash fouling. Is this engine burning oil at all? Plugs aren't cleaned any more, just replaced, if they need replacing earlier than the normal interval there is a reason why. The process of sandblasting them simply etches the surfaces, which in the case of the porcelain isn't desirable with these modern high voltage ignition systems, its just more potential for tracking and shorting.
toyboy3,
Dec 17, 5:39pm
How is the local mechanic to get his bonus if he doesn't sell parts whether needed or not
martin11,
Dec 17, 5:40pm
They did more damage to plugs than they were worth by sand blasting them . Would not use them on any high quality plugs .
bigfatmat1,
Dec 17, 5:50pm
What is the gap? If it's in excess of spec 1.1mm then they are worn out. The gap looks large on my phone but as frank says you must be burning oil
bjmh,
Dec 17, 5:50pm
remember the plug testers that went with the cleaners. I started my apprenticeship very green. one of the mechanics got to the plug testing stage,he says to me. "hold the plug,now hold this connector. now watch what happens when I hit the button " zappp . I couldn't lift my arm above my head all day.
jesus2000,
Dec 17, 6:04pm
Gap is 1.1mm
It's a feely highly magnified photo. To the eye you don't see the lumpiness and it looks like a gray tan colour. Engine goes through about 100 to 200ml of oil a month.
Run the car on BP 98.
gazzat22,
Dec 17, 6:30pm
What sort of running do you do?pottering around town ? For a start i would take it out on the highway and give it a good"ringing" then have a look at the plugs.Are they the correct heat range for the car?
jesus2000,
Dec 17, 6:49pm
Mostly open road running.
This is what the plug looks like at more normal life size.
Pic of new. And incedentaly they are a 1.3 mm gap (13suffix) They are showing signs of wear and usage in a harsh enviroment. multi valve engines can suffer from slight valve leakage and carbon build up. Add that with oil usage and yip. good mechanic compression test old plugs refitted and some injector cleaner in to engine intake whilst running at rpm OUTSIDE(LOL) new plugs good run and re-compression test WILL see more valve sealing and a better running engine. But only time mileage and oil usage will tell how tired the engine is and how much it eats plugs K
jesus2000,
Dec 17, 7:58pm
Thanks. Makes sense.
206k on the engine now.
mohaka,
Dec 17, 8:04pm
I'd still use them,could do with a clean
intrade,
Dec 17, 10:58pm
irridium dont show wear i had some in a nissan i sold and when it nuked its ignition coil i found the plugs where still in there 130,000km later , so yea they got replaced then with a new coil and new leads.
To a trained eye they show wear. It becomes obvious when compared to a new plug.
snoopy221,
Dec 17, 11:23pm
Experience also adds at 200 k and using oil. Possibly. Time to put FIVES in
ITR6F 13 change to ITR5F 13 One heat range higher allowing older engine to burn off deposits.
franc123,
Dec 17, 11:28pm
And what oil is being used in it?
jesus2000,
Dec 17, 11:49pm
Total 10w30
jesus2000,
Dec 17, 11:50pm
I may just try that. Thanks.
franc123,
Dec 18, 12:02am
Ok, I was thinking it may have been on 5w/30.
ntalke,
Dec 18, 12:11am
A 10/40 spec oil may be better,the 30 may be to thin at normal operating temps
franc123,
May 30, 2:32pm
Yep, I'd try a higher oil grade first before going onto a hotter plug and reassess after 8-10000 km. It may sort it.
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