I just replaced the spark plugs on my 87 GN with the AC Delco CR43TS plugs. As i removed what i assumed were the factory plugs i noticed that they were AC Delco R45TS plugs. Is this the correct factory plug? My dad bought the car new in 87 and claims to have never changed the plugs, which makes sense since the car only has 38k miles on it. But there is a possibility that he has changed them. I was just wondering because i havent heard of this part number anywhere else on this site, everyone talks about using the R43TS, and R42TS's. Thank You again! Bill Ritter
I forgot to ask the second part of my question. Is the CR42 a hotter plug than the CR43, or is it the other way around? I am just curious. Thanks.
Factory plugs were AC44TS.
One step colder is AC43TS (or CR43TS)
Two steps colder is AC42TS (or CR42TS)
Make sure to gap them at a tight 0.035".