2001/10/01 Caterpillar

Engine:

C-15 (S/N: 6NZ22193-UP)

C-16 (S/N: 7CZ01247-UP)

Truck Engine News SEBD6730, December 2000, "A New Configuration of Valve Springs Is Now In Production". That article has been replaced by this article.

Description of Change: A new dual valve spring configuration replaces the single valve spring on both the inlet valve and the exhaust valve. This change is effective in production with the serial numbers that are listed above. The dual valve spring configuration increases reliability. If a valve spring breaks, the new configuration minimizes the effects.

When you service a valve spring in the single valve spring configuration, dual springs should be installed on both valves under the same bridge. This will maintain an even balance under the bridge. New rotocoils must be installed in order to accommodate the dual springs. The rotocoils for single valve spring applications are not applicable to the dual valve spring configuration.

Adaptable To: The part numbers that are needed to service both valves under one bridge are shown in the table below:

Table 1

Part Number	Part Name	Quantity
175-7523	Inner Valve Spring	2
175-7526	Outer Valve Spring	2
186-2001	Rotocoil Assembly	2

The parts are adaptable to engines that are listed in the table below:

Table 2

Engine	Engine Serial Number
3406E	S/N:1LW1-UP
	S/N:1MM1-UP
	S/N:2WS1-UP
	S/N:5EK1-UP
	S/N:6DS1-UP
	S/N:6TS1-UP
C-15	S/N:6NZ1-22192
C-16	S/N:7CZ1-01246