In the process of doing the 90k service (doing it ourselves to save some $$$ I may add). There are several things I need advice on:
1) car is driven in San Diego, CA mainly as a commuter car. Temperature averages 70-85 degree F. Looking into getting a 10w-30 Full Synthetic, does Mobile 1 or Castro meet the Volvo requirements? If there's anyone in San Diego, what do you use?

2) Need to replace all spark plugs. What is the Bosch/Denso equivalent to the Volvo OEMs? Copper or Plat? The Volvo OEMs on the car now are 3 prong, does Bosch make a 3 prong?

3) Looking into changing the oxygen sensors (primarily the one before the cat and the one after). How many sensors are there and where are they located, for example I've see sensor 1, sensor 2, bank 1, bank 2, etc.

Any information is helpful and yes I've done many searches but could not find what I was looking for. Thanks in advance everyone
The car is a 2001 s60 2.4L non-turbo with 89k miles.

 

1.Castrol and Mobil both meet Volvo's standards.
2.Get Bosch platinums they will be fine. Bosch are OEM.
3.Your car should only have 2 sensors. Buy OEM or Bosch direct replacements.

 

Why would you replace Oxygen sensors if they arent causeing running problems or throwing DTC's?

 

You're right they're not throwing any errors. Although when idling, the cars revs up and down between 1k to 500 rpms. This lasts anywhere between 20 seconds to several minutes. And when in reverse, the engine feels sputtery or shakey, its very unusual. Its revved down so low that the engine feels like its going to die. My father in law, who is an ex master mechanic for eurpoean cars, said that it could be a tune up job, spark plugs, oxy sensor, or TB cleaning. I'm just trying to get some info just in case i decide to change the sensors. Could it be some other issue?

 

Im gonna assume this is a non turbo 5cyl, which means its a Denso car, try giving the TB a good cleaning. id say that would fix it, im willing to bet it is NOT the oxy sensors. The car is so sensitive with its emissions that it would throw a DTC for it. And this is coming from a Current master tech..

 

Thanks...I'll give that a shot this weekend when I work on the car.