Platinuum Spark Plugs

[terravista]

We recently had problems with a car that had symptoms of the overdrive cutting on and off about 4 times a second when applying load between 75kph and 90kph. This didn't happen with the overdrive turned off.
After a few hundred dollars, the culprit was the you beaut platinum spark plugs failing. This was in a vehicle that was designed to use platinum plugs, so the voltage should be correct.
These plugs are supposedly good for 100 000k's, but did not last 30 000k.
At a price of these plugs, this isn't good enough. (Maybe I should have used standard Supercheap plugs)
I won't try to name and shame the brand (rhymes with Dosh) because I don't have any evidence that the faults were of the manufacturers fault, even though it's hard to see otherwise, but the mechanic who fiddled around for a while checking the gearbox, moving onto the coil packs, and settled on the plugs, said he had come across a few failures with platinum plugs.
The central electrode had burned, melted, broke or whatever, which resulted in a gap of around 2.5mm to 3mm.
If you have a petrol vehicle with platinum plugs, and the car is running rough or "missing" it may be worth your time looking at the plugs as a starting point before moving onto more expensive items.
Cheers
Ian 

[bobnrob]

A few years back, I completely stripped down, painted & rebuilt the mechanical side of a generator for my ol' man.
You think I could get the thing to run again?...should've taken the NEW plug out, & put the old one in hours earlier 

[eldo]

if you can get access to the plugs i would suggest good old NGK standard plugs, so use like br6es etcand change every 20,000km , available at supercheap for about 4 bucks each. if they are like mitsubishis and you need a rocket scientist to change them stick with the platinum series plug but change to OEM or NGK or even ND.

[bussoboy]

yup, from many years of supplying both quality and crap spare parts i would never use anything other than NGK when it comes to spark plugs

having been out of it for years now..........do they still make NGK iridium plugs?..........very pricey but the ducks nuts when it came to plugs

[Moto Mech]

yup, from many years of supplying both quality and crap spare parts i would never use anything other than NGK when it comes to spark plugs

having been out of it for years now..........do they still make NGK iridium plugs?..........very pricey but the ducks nuts when it came to plugs

Yes, they still make NGK Iridium plugs. I use a mixture of both std and Iridium in NGK and have NEVER had a dud spark plug yet......touch wood

[fishfinder]

if it is easy access to the plugs as said change to standard plugs and continue changing them every 10 000 km - platinum plugs last longer but they do not spark as clean as standard plugs so fuel economy not as good I have done fuel consumption tests with different plugs and oils and found nippon denso plugs to be the better plug and the lowest price of the better brands

[terravista]

Thanks people.
The car now has standard plugs, but I haven't taken notice of what brand.
If I had read my post and knew the information before I wrote it, I could have saved nearly $400.
Bugger. (it is a Toyota)
Cheers
Ian