Do you guys ever change the coils just because they are getting some miles on them or wait until they go out?

The reason I ask is because I've changed them out on my chevy truck before they went out and it seemed to have more power and mileage. Coils do become weaker as they age.

Do you use replacement Delco coils or aftermarket. What is the Delco # for our coils on the 3800? Thanks.

Wayne

 

Ive never heard of anyone replacing them because of miles or age, just if they go bad. I dont think they are like spark plugs, where you change them after a certain amount of miles.

 

I'm on 166,000 miles on my stock coils.

I think they are a change if you are misfiring / other issues that aren't resolved by spark plugs / wires

 

Wayne, you want to use Delco replacement coils. Make sure that you buy L67 coils if you do decide to replace yours- L36 coils are weaker than L67 coils, and they have separate part numbers.

The aftermarket coils out there (MSD, Accel, etc) are all made to L36 spec, and are actually weaker than stock L67 coils.

 

Ok, thanks. I didn't know there were a difference between the two coils. I doubt I will change them anytime soon but even after a tuneup minus the plug wires, I only got 23 mpg with mostly highway miles and that was me figuring up the mileage and not using the display. The display said 27 mpg so it was off pretty bad. I was hoping for a little better MPG.

Wayne

 

I guess I don't see how they could wear out over time. From my understanding, a coil is just comprised of two separate windings of wire (with one set having significantly more windings than the other)- and that the voltage difference is determined by the number of each winding and the input voltage. So you can't really lose some windings over time or you'd break the circuit and it wouldn't work at all. I could be wrong about that though.

I've only had coil packs go bad- one of mine suddenly died one day, the other sporadically failed (going back and forth from working to not randomly- I assume due to a corroded connection inside or something).

 

If you want better gas mileage don't do the math in the winter time when your gas mileage is going to be the worst. Warm ups + fuel additives = loss of MPG.

Now if you want to start the improvements of your MPG, you should do some basic modifications, such as letting your car breathe better. This will give you more fun on the pedal, and more MPGs.

My car can easily get 32-34 MPG because I have done mild modifications and a tune.