2008 Volvo V70 Owner's Manual - Page 236

When weather temperature changes occur, tire inflation pressures also change. A 10-degree temperature drop causes a corresponding drop of 1 psi (7 kPa) in inflation pressure. Check your tire pressures frequently and adjust them to the proper pressure, which can be found on the vehicle's tire information placard or certification label. Checking tire pressure Cold tires Inflation pressure should be checked when the tires are cold. The tires are considered to be cold when they have the same temperature as the surrounding (ambient) air. 248 06 Maintenance and specifications Wheels and tires This temperature is normally reached after the vehicle has been parked for at least 3 hours. After driving a distance of approximately 1 mile (1.6 km), the tires are considered to be hot. If you have to drive farther than this distance to pump your tire(s), check and record the tire pressure first and add the appropriate air pressure when you get to the pump. If checking tire pressure when the tire is hot, never "bleed" or reduce air pressure. The tires are hot from driving and it is normal for pressures to increase above recommended cold pressures. A hot tire at or below recommended cold inflation pressure could be significantly under-inflated. To check inflation pressure: 1. Remove the cap from the valve on one tire, then firmly press the tire gauge onto the valve. 2. Add air to reach the recommended air pressure. 3. Replace the valve cap. 4. Repeat this procedure for each tire, including the spare. 5. Visually inspect the tires to make sure there are no nails or other objects embedded that could puncture the tire and cause an air leak. 6. Check the sidewalls to make sure there are no gouges, cuts, bulges or other irregularities. NOTE If you overfill the tire, release air by pushing on the metal stem in the center of the valve. Then recheck the pressure with your tire gauge.