I need to know what type of oil to use in my 1998 Volvo V70 can someone please help me?

Mineral 15w40 type oil

10w30 full synthetic is the most commonly used and recommended oil. I use 0w40 synthetic in my car and it's fine, but the lifters are a little noisier than when I was running 10w30. Being in Texas, I recommend 10w30 or 10w40. Whatever you do, do NOT use 5w30. It is not suitable for this engine in your temperature range.

Diesel oil Rowe?

Rotella T6 5w40 is another option that is known to work well on these cars, speaking of diesel oil.

I got the recommendation off of this sight... http://cararac.com/engine_oil/volvo/v70.html

The 15w40 just seems excessively high. I've never heard of that used in a Volvo.

The weight of oil that you use needs to be guided by your experience. If the car does not use oil when you use 5W-30 I would go with that as heavier oils reduce your fuel economy a little. Should your car use too much oil (more than a quart between changes) go with the next heavier grade and see how that works.

You should run what the manufacture recommends for the weight oil to be used in your engine. This is out of the owners manual for that car. "NOTE: SAE 15 W-40 oil should only be used in extreme operating conditions such as trailer towing in sustained ambient temperatures over 104° F (40° C). However, SAE 10W-30 synthetic oil would be a better alternative in such conditions. SAE 15W-30 should not be used under normal operating conditions."

Here is where you can find the owners manual for this car.. http://new.volvocars.com/ownersdocs/1998/1998_SV70/98sv70_000.htm#contents

As I said, 5w30 is out of the temperature range according to the owner's manual. Look up RobertDIY on YouTube. He has PLENTY of videos about people using 5w30 in these cars and having issues. Although, at operating temperature, 10w30 and 5w30 should be the same viscosity.

Oil type for 2002 volvo v70 t5turbo wagon