I had a little trouble removing the plugs from our 2001 S40. The neoprene(?) boots at the end of the plastic plug connectors stayed stuck to the plugs when I pulled the ignition wires off plugs 1 & 2. I demolished one of the boots trying to tease it off with needle nose pliers. I was able to tease the second one off using a pick tool with a 90 degree bend in the end.

1) How important is this boot? Can I run without it?

2) Can I buy just the boots anywhere, or to I need to purchase the entire plug wire set? I had no luck locating them at myswedishparts.com or thevolvosite.com.

Here's the boot:

 

I would buy a new set of wires.

 

you need a new set now.

 

When you reinstall the plugs, put a dab of copper paste on the plug threads so that the plugs will come out easily next time you want to change plugs. On the rubber boot, smear a bit of silicone (dielectric) paste inside it and they will be easily removed "the next time".

r.

 

 

Belated update. I drove the car about 30 miles with the boot missing from the #1 plug. I'd get a noticable stubble and flashing check engine light upon deceleration. Otherwise the car ran okay. A new plug wire with its boot cured things.

I use Anti-Seeze on the plug threads and a good dose of silicone grease on the plug boots. We'll see how things come apart in another 30K.