Oil Consumption Test
Oil consumption test
General
Some oil consumption is normal when an engine is running. The oil consumption varies depending on different factors:
- The condition of the engine (how well the engine is maintained)
- Blocked or damaged air filter
- Driving conditions - large loads, or excessive idling
- Oil grade and viscosity
- Cylinder capacity - in general a larger motor consumes a greater amount of oil than a smaller engine
- Engine power - a stronger engine consumes more oil than a smaller powered engine
- Oil level - too high a level (above the maximum mark on the dip stick) results in increased oil consumption.
Normal oil consumption
Running-in period
The oil consumption can be as much as 1 liter per 1,000 km during a running-in period of approx. 5,000 km if the engine is new or replaced (replacement of piston ring).
Driving between 5,000 and 150,000 km
Normal driving: up to 0.25 liters per 1,000 km is considered normal oil consumption.
Driving at high speed/with heavy trailer: up to 0.40 liters per 1,000 km is considered normal oil consumption.
Mountain/alpine driving: up to 0.50 liters per 1,000 km is considered normal oil consumption.
The above stated values for oil consumption can be used as guidelines if there is a suspicion that oil consumption is unusually/abnormally high.
Note! The oil consumption can be as much as the following at 150,000 km. The oil consumption can be approx. 0.35 - 0.55 liters per 1,000 km under all conditions.
To determine the exact oil consumption a test drive of at least 1,000 km must be performed under controlled conditions. The oil must be weighed before and after the test drive. This way the exact oil consumption can be calculated.
Abnormally high oil consumption
If the customer points out that the car consumes an abnormal amount of oil, the checks below must be carried out before carrying out corrective action.
- Ask the customer what their driving conditions are (see General causes of high oil consumption)
- Check for oil leaks
- Check that the crankcase ventilation is not blocked
- Check that the correct dip stick is in the engine. Check that the dip stick is pushed down as far as possible
- The car must be parked on level ground when measuring the oil. The engine should be driven at normal operating temperature on the road (not idling) for 30 minutes. The engine must then be left for 15 minutes before noting the oil level.
General causes of high oil consumption
Overfilling
If the oil has been filled above the recommended maximum level, oil is forced up against the cylinder walls and is ejected through the crankcase ventilation. The oil level must not be filled above the maximum mark on the dip stick!
Oil grade
Using a non Volvo recommended oil grade can cause increased oil consumption. The oil contains a larger amount of volatile molecules if the oil is too thin. Thin oil has difficulty in maintaining a comprehensive oil film on the cylinder walls at higher temperatures. This results in increased engine wear and increased oil consumption
Hard driving
Long and continuous driving at high engine speed (RPM) causes high engine temperature. The oil thins and consumption increases. Hard cornering at high engine speed (RPM) causes the oil to be forced against the side of the cylinder block and against the cylinder walls, resulting in increased oil consumption.
Mountain driving
Numerous and long periods of regular engine braking also causes high engine temperature. More oil is sucked into the cylinders due to an increased negative pressure in the intake pipe.
Idling
Driving the car in urban traffic conditions, where the engine may be running for long periods but only covering short distances, does not necessarily increase oil consumption but the ratio of oil consumption to distance travelled may be misleading.
Climate
In hot climates, the engine is required to work harder at a higher temperature. This increases oil consumption.
Mechanical causes of high oil consumption
Leaks
Worn crankshaft and crankshaft seal, external leakage, for example leaking gaskets.
Crankcase ventilation
Overpressure in the crank case caused by blocked crankcase ventilation.
Pistons and piston rings
Worn piston ring groove. Worn, scratched, broken or damaged piston rings. Blocked scraper rings. Incorrectly installed piston rings.
Cylinder walls
Worn or scratched cylinder walls.
Valves
Worn valve guides or valve stem. Worn, damaged or missing valve stem seals.
Cylinder head
Internal leakage between the oil ducts and leakage to the combustion chamber.
Measuring the oil consumption
General
There are two methods of determining the oil consumption. The oil is measured using a dip stick in the first method, before and after driving a test distance of 2000 km. This gives a sufficient first indication of the oil consumption. The second method consists of weighing the oil in the sump after driving 1000 km.
To reach as a correct result as possible, with both methods, the car must be driven to normal operating temperature (not idling) for 30 minutes before noting the oil level or draining the oil. Change the oil and replace the oil filter to ensure that a Volvo approved oil is used in the engine during the test period. Also replace the air cleaner (ACL) before measuring. The car must be standing on a flat surface and in the same position when measuring or weighing before and after the driven test distance.
Measuring using the dip stick
Replace the oil, oil filter and air cleaner. The oil must be Volvo approved.
Drive the car to operating temperature for 20-30 minutes (not idling). This is so that the oil reaches normal operating temperature.
Switch off the engine. Leave the engine switched off for 15 minutes.
Check the oil level. Top up with oil if necessary. Fill to the maximum mark on the dip stick.
Run the engine for 5 minutes so that the existing oil and the additional oil mix.
Switch off the engine for 15 minutes. Note the oil level on the dip stick. Note the odometer setting and vehicle data on the included form, Form for measuring oil consumption.
Drive the car 2000 km, or until the oil level has dropped to the minimum mark on the dip stick.
Drive the car to operating temperature for 20-30 minutes (not idling). This is so that the oil reaches normal operating temperature.
Switch off the engine. Leave the engine switched off for 15 minutes.
Measure the oil level on the dip stick using a sliding gauge. Note the result.
Complete the information on the form.
Weighing
Drive the car to operating temperature for 20-30 minutes (not idling). This is so that the oil reaches operating temperature.
Drain the oil from the oil trough for 15 minutes. A large amount of oil is collected in the cylinder head when the car is running. This factor, together with the design of the splash guard in the oil pan, means that it takes a long time for the oil to drain out of the engine. The oil must not be reused.
Warning! Take care when draining the oil. Use protective goggles and protective gloves. Hot oil can cause personal injury!
Replace the oil filter and air cleaner.
Fill with the specified amount of Volvo approved engine oil.
Drive the car to operating temperature for 20-30 minutes (not idling). This is so that the oil reaches normal operating temperature and the oil filter fills.
Carefully weigh an empty clean container (± 1 gram).
Drain the oil from the oil trough into the container for 15 minutes.
Warning! Take care when draining the oil. Use protective goggles and protective gloves. Hot oil can cause personal injury!
Carefully weigh the container + oil.
Fill the engine with the weighed oil. Ensure that as much oil as possible leaves the container.
Weigh the empty container. The container may weigh more than it did the first time due to the remaining oil film. The difference in weight is taken from the weighed oil weight.
Note the oil weight odometer setting and vehicle data on the included form, Form for measuring oil consumption.
Drive the car 1000 km, or until the oil level has dropped to the minimum mark on the dip stick.
Ensure that the engine is at normal operating temperature. Drive to normal operating temperature if necessary for 20-30 minutes (not idling).
Carefully weigh an empty clean container (± 1 gram).
Drain the oil from the oil trough into the container for 15 minutes.
Warning! Take care when draining the oil. Use protective goggles and protective gloves. Hot oil can cause personal injury!
Carefully weigh the oil + container. Deduct the weight of the container.
Complete the information on the form
If abnormal oil consumption is discovered when measuring, the engine needs to be remedied as follows.
Corrective action for high oil consumption
Conditions
A new and improved type of piston ring was introduced for naturally aspirated engines from model year 1999 inclusive and for turbocharged engines from model year 2000 inclusive. From model year 2000 inclusive the same piston rings are used on both naturally aspirated engines and turbocharged engines.
A car with an engine with the new piston rings can be expected to use 0.05-0.15 liters of oil every 1000 km.
A car with an engine with the earlier piston rings can be expected to use 0.10-0.20 liters of oil every 1000 km.
If the engine consumes more than 0.4 liters of oil every 1000 km, the following checks must be carried out to check whether the oil consumption problem is in the cylinder head, crankcase ventilation or piston ring and sleeve surface.
Check
Remove the intake manifold.
Check to see if there is an oil film or drops of oil in the cylinder head intake passage and/or oil on the valve stem and top of the valve crown.
Conclusions
If there is not an abnormally large amount of oil in the intake passage and valves and the oil consumption gradually, from being acceptable, begins to quickly increase, or consumption is between 0.30-0.80 liters per 1000 km, the problem is in the piston, piston ring or cylinder sleeve surface.
Faults in valve stem seals for example, or internal leakage in the cylinder head cannot be completely ruled out.
If the oil consumption has always been high, or there are traces of oil in the intake passage and valves, or the oil consumption is above 0.80 liters every 1000 km, the problem is probably in the cylinder head.
The cause could be leaking valve stem seals, internal leakage in the cylinder head or a fault in the crankcase ventilation (other than a blockage).
Corrective actions
If the problem seems to be in the crankcase ventilation, this must be thoroughly checked and remedied if necessary, before reconditioning or replacing the cylinder head.
If the problem seems to be with the piston, piston ring or cylinder sleeve surface, the engine should be reconditioned or if necessary, replaced.
Reconditioning
Replacing piston rings
A corrective action is to replace the two lower piston rings (scraper ring and oil ring).
If the upper piston ring (compression ring) is undamaged it must not be replaced. Increased oil consumption may result if the compression ring is replaced.
Caution! Check that the upper piston ring (compression ring) faces the right way (see below)!
It is important that the uppermost and centre rings are installed the correct way up.
The lower ring can be installed any way up.
Distribute the piston ring openings as follows.
Early version
A. Compression ring
This is marked with text or with a circle. The marking must be facing upwards! It may be difficult to read the text, a magnifying glass may be required.
B. Scraper ring
The cut out must be turned downwards. The text must be on the top of the ring.
C. Oil ring
Earlier versions of the oil ring are not marked and can be installed any side up.
Later versions of the oil ring are divided into 3 sections. These slotted rings can be installed with either side facing up.
Caution! New versions of the piston ring assembly cannot be combined with earlier versions of the piston!
Late version
Conclusions for corrective action
Replacing piston rings
As a first corrective action the piston rings should be replaced. Normally only the scraper ring and the oil ring must be replaced. The compression ring should only be replaced if absolutely necessary.
Replacing valve stem seals
If traces of oil are found on the valve crowns, in the ducts or on the valve stems, the valve stem seals should be replaced.
Thoroughly check the cylinder head. Check for internal leakage.
Replacing the cylinder head
If traces of oil (described above) are found and faults are found on the cylinder head, internal leakage for example, the cylinder head must be replaced.
Replacing the cylinder block and pistons
If damage is found in the cylinder block (worn cylinder bore, deep scratches etc.) the cylinder block, pistons and piston rings must be replaced.
Replacing the engine
The engine must be replaced if the problem cannot be remedied using the above corrective actions.
Form for measuring oil consumption
