Engine Oil - Viscosity Recommendation
90volvo09Subject: Product
CARS
Oil Viscosity
Group
17
Date: No.
December 1990
THIS SERVICE MANAGER BULLETIN APPLIES TO U.S. AND CANADIAN DEALERS
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"When Enough is Enough"
Times used to be that, when it came to oil viscosity, "heaviest was best". Nowadays, in these times of improved engine oils, it may be more appropriate to say "enough is enough". Using an excessively high engine oil viscosity could be robbing a car and its engine of fuel economy, cooling capacity, and cold start performance.
Volvo's recommended oil viscosity in most climates and conditions is 10W-30 (see chart below). The maximum acceptable viscosity, which is reserved for extreme duty only, is 15W-40.
Extreme engine duty is defined as driving conditions that tend to raise oil temperature excessively, such as sustained mountain driving, trailer towing, etc.
An exception to the above restriction could be high mileage engines (above 100,000 miles) operating in hot climates. These engines may require a heavier viscosity oil to maintain oil pressure and reduce oil consumption.
Oils with viscosities heavier than 15W-40 are not approved by Volvo.
Using a heavier than necessary oil viscosity will tend to:
^ Increase starter motor power draw and lower engine cranking speed during cold starting. This will lead to increased starting time or poor cold starting performance.
^ Increase the time lag during cold start that it takes for the oil flow to reach the furthest extent of the engine lubricating system. This can contribute to increased engine wear during cold start up.
^ Reduce fuel economy due to higher frictional losses associated with high viscosity fluids and higher pumping losses needed to pump a heavier viscosity oil through the engine.
^ Reduce engine cooling effectiveness due to a comparatively slower flow rate of oil associated with heavier viscosity oils.
Correct API Service Grade is "SG". Oils that contain designations SG/SF, SG/CC, SG/CD, SGXE, or any combination of these containing the "SG" designation are acceptable. Other oils are not acceptable in Volvo Engines.