Engine Front Cover Area - Grind/Rattle Noise
BULLETIN NO.: 94-T-55ISSUE DATE: December, 1994
GROUP/SEQ. NO.: Engine-12
CORPORATION NO.: 486111
TECHNICAL INFORMATION BULLETIN
SUBJECT:
Grind and/or Rattle Noise from Engine Front Cover Area
(Replace Timing Chain Assembly, Tensioner and Guides)
MODELS AFFECTED:
1993 Saturns built between and including VINs PZ233317 to PZ293164, equipped with DOHC (LLO) and SOHC (LKO) engines.
CONDITION:
Some customers may comment about a grind and/or rattle noise coming from the engine compartment under all operating conditions. The noise is more evident near the engine front cover with the hood open.
CAUSE:
On these vehicles, the oil bleed hole on the timing chain tensioner assembly was increased from 1 mm to 1.6 mm. The increased bleed hole size may cause the timing chain tensioner assembly plunger to seize and/or stick in the timing chain tensioner assembly plunger bore. This may cause premature wear of the timing chain assembly and timing chain guides, causing a grind and/or rattle noise.
IMPORTANT:
The illustration shows the difference between the 1 mm and 1.6 mm oil bleed hole.
CORRECTION:
Perform the following procedure to repair the condition.
PROCEDURE:
1. For DOHC (LLO) engines, remove the camshaft cover and inspect the timing chain assembly to upper timing chain guide. The timing chain assembly should be tight against the upper timing chain guide.
If the timing chain assembly is not tight against the upper timing chain guide, replace the timing chain assembly, timing chain tensioner assembly and three timing chain guides. (Refer to "Front Cover-In-Chassis" procedure in the "1991-1994 Engine Mechanical Service Manual.")
If the timing chain assembly is tight against the upper timing chain guide, refer to the appropriate diagnosis in the "1991-1994 Engine Mechanical Service Manual."
2. For SOHC (LKO) engines, remove the valve rocker arm cover and inspect the tightness of the timing chain assembly on the camshaft sprocket. The timing chain assembly should be tight around the camshaft sprocket.
If the timing chain assembly is not tight around the camshaft sprocket, replace the timing chain assembly, timing chain tensioner assembly and two timing chain guides. (Refer to "Front Cover-In-Chassis" procedure in the "1991-1994 Engine Mechanical Service Manual.")
If the timing chain assembly is tight around the camshaft sprocket, refer to the appropriate diagnosis in the "1991-1994 Engine Mechanical Service Manual."
PARTS REQUIREMENTS:
CLAIM INFORMATION:
To receive credit for this repair during the warranty coverage period, submit a claim through the Saturn Dealer System. See illustration.