Hi, recently I replaced my spark plugs (6). I bought them from the dealer, opened one of them(box), it was from Bosch(single pin) and gave them all to a mechanic to replace later when I looked at the old spark plugs, that came out of my car, they were from NGK ( 2 pins). I checked with the dealer, who told me that both are same, just two different companies. Now I'm not sure whether all 6 of them were from Bosch or some from NGK as well.
Is there any harm if I use some spark plugs with Bosch(1 pin) and others with NGK (2 pins)??
My car works just fine.

 

There should be no harm done to your car as long as all the spark plugs work and their gap is all the same which should also match the required gap of your vehicle. It's similar to when you have a faulty spark plug, you don't replace all of them, just a single one.


-Nick

 

While it's likely not a 'big' deal, spark plugs are most certainly not all the same. The plugs could be different heat ranges for all you know. Considering the meager cost of plugs, there is no reason to not be running the exact same plugs all around.