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.
- Check the engine for external oil leakage and the air intake and
PCV systems for excessive oil pull over.
- Change the engine oil and filter.
- 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.
- Inform the customer an oil consumption test is now in progress
and any oil added must be documented.
- Record the vehicle's mileage, date of oil change and exact location
of oil level on the Customer Service Order.
- 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.
- 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.
- 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:
| • | Lifters worn, dirty or failed |
| • | 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.
