Hi -

I was thinking about trying to change out a bad coil.

How do you know which coil is bad? thanks!

 

I tried checking the ohms but in the end replaced both of them. It was not until much later that I learned there is more than resistance at play. See the long plastic piece that sticks down over the spark plug? After many hot/cold cycles it tends to crack. And these tiny cracks let the spark jump to the head instead of the plug down inside the spark plug tube. The problem is that with the coil in place you cannot see or hear the spark jump. Same with the plug wires. The 2 coils may be fine but your spark is leaking to the head under one of the spark plug boots.

Is your car acting up? How long since you gave it a tune up? If it's gone 100k+ miles you should replace it all: 2 coils, 2 wires, 4 plugs.

 

thanks for the reply.

yes - the car is riding rough, especially when you "punch it" on the highway, and when you crank it up. the check engine light comes on and off all the time.

i had my mechanic do a combination of these services in the last 50k miles. i'll have them check the records and see about any warranty, and get these things replaced.

next, i need to get the cam seals done. that is a huge expense that i am dreading. i wonder how long i can put it off.

 

As long as you want!

Seriously, how bad is it? Leaking oil on the ground? Is there any oil on the timing belt?

 

it's leaking a few drops a day on ground = about 1 quart every 6 months.

the timing belt is SOAKED in oil.

called a volvo specialty shop who has all the tools, and they can do it for $680, including a new belt. that's about $600 less than the local volvo dealership.

 

I would not hesitate then. Mine started leaking from the CVVT gear and ended up causing the timing belt to slip which bent all 8 exhaust valves. You really don't want to go that route.

 

Will do. Got another problem! My shop replaced the coils and wire, but now the car wont start! they are getting a software error?!?! ever heard of this?

 

I've never heard of that just from a tune up.

 

found this on a web blog:
According to my mechanic (20+ years of Volvo experience) the connector between the antenna ring and the wiring harness sometimes causes problems - taking it off, spraying it with contact cleaner, and re-seating it fixes these. It could be that the vibrations from hitting the key were enough to overcome the resistance and allow the key to be recognized & the car started.

i had my antenna replaced, too! interesting