I have been in the market for new plugs for my 2002 S80 (non-turbo).

In my search for new plugs at local shops and online, I finally ran into a deal that I could not refuse. I was on the Rock Auto website looking at all the plugs offered and noticed the Bosch 4503 Platinum IR Fusion plugs were being sold at $5.80ea, but there was a note about a rebate. I clicked the link and the rebate is for $4.00 per plug! Net cost is $1.80/plug, plus $3.36 shipping.

You can download the rebate form right from their website, which makes things quite easy, and you can pay with paypal if you like- easier still. This rebate is running 9/1/11 through 12/31/12. I suppose you can use this rebate no matter where you buy the plugs, but I had not seen it anywhere else.

Plugs arrived in a couple of days and I installed them today. Turns out I had Bosch Super plugs- probably the cheapest Bosch plug available- and the ground electrodes seemed fairly worn. Anyway, the new plugs are 4 pronged (meh) with all manner of fancy metals here and there- but so far they seem to work fine. I will get back later with any fuel mileage updates, should they go north or south.

Platinum Ir Fusion
www.RockAuto.com

 

Bosch are crap plugs in these Volvos. I replace Bosch plugs with NGK plugs about a dozen times a month. They cause random misfires under high load situations. (IE mountain driving, on ramp, stoplight)

Food for thought.

 

So far, so good. No misfires, runs strong, and fuel mileage has improved by 2 mpg according to the trip computer.

 

i am doing a head gasket on my 99 s80 t6 and they have bosch plugs which i dont like. but i love ngks in other cars glad to here they work in volvos too. i will be sure to put them in when im finishing up.

 

My trip computer shows I am getting about 2mpg better with these plugs. Bear in mind, this could be just because the old plugs were old, or because they were not right for this car (Bosch Super).

Also I must report the car takes about a turn or two more to start now. And sometimes it doesn't start on the first crank. I cant say if this is plug related or some other problem. If it is plug related, I will be trying something else, as +2mpg does not trump buying a new starter or battery prematurely. At 130K miles, it might be time for a TB cleaning, or some other such "tune up".

 

Which NGK plug seems to work best in the 2.9 s80's?

 

Here are the oem volvo plugs I took out. When I took them out, I noticed that the center electrode is huge by comparison to the plugs I put in - made me wonder if I should be changing them.https://skydrive.live.com/?cid=9c7bb...2245F863%21427

 

the image wont load, as the host wants me to sign in to see the photo.

As for electrode size- it varies by plug type, brand, etc.... the center electrode on the Bosch plugs I used is tiny- and as I recall- is iridium coated platinum. Copper plugs usually have a large center electrode.

I think the real question is, does it start and run good, and is the mileage as good or better than before? If so, I would not bother changing new plugs.