My car just changed new engine mount, but still slightly shaky, I took coil out last week. Can anyone tell how bad those coil is? do I have to replace the new one. This coil only run like 10K miles. thank you guys...

 

I'm afraid you can't tell anything about the coil condition from the white spots on the back



If it's melted...sure.....

You would have better luck looking at the plug from that coil and see what it is doing

If you have 30K or more...spend the $150 and get a new set..save you a lot of "figurin"

 

I replace mine yearly regardless of spots (which tell you nothing). The coils are not robust enough for our cars.

 

Yeah, even if you use the recommended procedure for checking them with an Ohm meter, it still doesn't really tell you!