Eclipse L4-1997cc 2.0L DOHC (1991)
Lash Adjusters: All Technical Service Bulletins
Engine - Automatic Valve Lash Adjuster Noise
NO.
TSB-91-11-009
DATE
May, 1991
MODEL
All models with Automatic Valve Lash Adjusters
SUBJECT:
EXCESSIVE NOISE FROM AUTOMATIC VALVE LASH ADJUSTERS
PURPOSE
This Technical Service Bulletin (TSB) describes a possible cause of excessive automatic valve lash adjuster noise and provides a corrective procedure.
AFFECTED VEHICLES
All vehicles equipped with automatic valve lash adjusters.
Figure 1. Automatic Valve Lash Adjuster (cut-away view)
DESCRIPTION
The most likely cause of excessive automatic lash adjuster noise is the presence of air in the high pressure chamber. (Refer to Figure 1).
Before replacing any of the automatic lash adjusters on a vehicle with excessive valve noise, perform the following procedure. This procedure will bleed
unwanted air out of the adjusters and provide positive evidence that there is no need for replacement.
Note:
Some customers may comment on a slight valve tapping noise heard upon initial vehicle start-up (especially if the vehicle has not been operated
for more than one week). This noise disappears after normal engine temperature is reached. It is important to let the customer know that this is a
normal condition and not a cause for concern.
PROCEDURE
1.
Check the oil level in the crankcase. If the oil does not require changing, top it off to the full mark on the dipstick. If the oil requires changing,
replace the oil and, when required by the maintenance schedule, the oil filter.
2.
Start the engine, check for oil leaks, and warm the vehicle up to normal operating temperature.
3.
If the valve noise is still present after engine warm up, air may be trapped in one or more of the automatic lash adjusters. To bleed out the air,
perform the following steps:
a. Gradually increase engine speed from idle to 3,000 rpm during a 30-second interval. Then, decrease engine speed for another 30-second
interval until it returns to idle.
