For 1990-2009 cars

Excessive oil consumption (not due to leaks) is the use of 0.9 L (1 qt) or more of engine oil within 3 200 kilometers (2,000 miles). The causes of excessive oil consumption include the following conditions:

• | External oil leaks. Tighten bolts and/or replace gaskets and oil seals as necessary.

• | Incorrect oil level or improper reading of oil level indicator. With the vehicle on a level surface, allow adequate drain down time and check for the correct oil level.

• | Improper oil viscosity. Use recommended SAE viscosity for the prevailing temperatures.

• | Continuous high speed driving and/or severe usage.

• | Crankcase ventilation system restrictions or malfunctioning components.

• | Valve guides and/or valve stem oil seals worn, or the seal omitted. Ream guides and install oversize service valves and/or new valve stem oil seals.

• | Piston rings broken, improperly installed, worn, or not seated properly. Allow adequate time for rings to seat. Replace broken or worn rings as necessary.

• | Piston improperly installed.

### Oil Consumption Test Procedure

Important: Complaints of high engine oil consumption are not always thoroughly investigated before major repairs are performed. During initial engine break in, it is normal for the engine to use from one to three quarts of oil during the first 4,800-9600 kilometers (3,000-6,000 miles), depending on driving conditions.

1. Check the engine for external oil leakage and the air intake and PCV systems for excessive oil pull over.
2. Change the engine oil and filter.
3. Warm the engine up and check the oil level after approximately 10 minutes with vehicle on a level surface. Note exactly where the dipstick reads, relative to the dipstick MAX mark.
4. Inform the customer an oil consumption test is now in progress and any oil added must be documented.
5. Record the vehicle's mileage, date of oil change and exact location of oil level on the Customer Service Order.
6. Have customer check the engine oil level at each fuel fill and return the vehicle if oil level is at the "MIN" mark. If the oil level remains in the "CROSS HATCH" area, have the customer continue operating the vehicle for a minimum of 3,200 kilometers (2,000 miles) before returning the vehicle for final oil consumption verification.
7. If the engine uses more than one quart of oil in 3,200 kilometers (2,000 miles), after the initial 4,800 kilometers (3,000 miles) break in period, document the oil consumption usage on the Customer Service Order and continue with the following checks.
8. If the engine is using oil, perform a compression test. Refer to "Engine Compression Test" procedure in this section of the service manual.

• | If cylinder compression is found within acceptable limits, replace the valve stem seals.

• | If compression is not found within acceptable limits, perform an engine cylinder leakage test, crankcase pressure check, and repair as necessary.

### Valve Train Diagnosis

A light tapping at one-half engine speed, or any varying frequency, can indicate a valve train problem. These tapping noises increase with engine speed.

Before attempting to judge the valve train noises, thoroughly warm up the engine. By doing this you will bring all engine components to a normal state of expansion. Also, run the engine at various speeds and listen for engine noises with the hood closed while sitting in the driver's seat. The causes of the valve train noise include the following conditions:

• | Low oil pressure

• | Broken valve springs

• | Sticking valves

• | Lifters worn, dirty or failed

• | Worn valve guides

• | Excessive valve stem to guide clearance

• | Failed oil drain back valve

### Vehicle Speed Sensitive Vibration Diagnosis

Definition: Vehicle speed sensitive vibrations can be heard or felt as the speed of the vehicle (mph) varies.

The operating speed of the engine (rpm) does not effect a vehicle speed sensitive vibration.