Cylinder Head - Coolant Loss/Coolant in Oil
Number8902
Group
1
Model
944S9 928 S4
Part Identifier
1570
January 20, 1989
Subject:
Coolant Loss/Coolant in Oil
Loss of coolant or coolant in the engine oil may, among other reasons, be caused by cracks in the cylinder head cooling jacket. These cracks may begin in the area of the exhaust valve and extend toward the cylinder head mounting bolt holes. The figures show possible fracture locations.
If coolant loss with no visible external leaks is found, the cylinder head should be checked. To test an installed cylinder head, remove the cylinder head cover and apply 1 bar maximum (14.7 psi) pressure to the cooling system. Check for leakage of coolant in the areas of the arrows and/or pressure loss.
For 944S cars, an improved cylinder head is available. The part number is unchanged.
For 928 S4 cars, a new cylinder head PN 928 104 014 03 is installed from Engine No.:
81K00121 Manual Transmission
81K05240 Automatic Transmission
Refer to Technical Bulletin Group 1, No. 8821, for mounting bolt information.
The previous version cylinder head, PN 928 104 014 02 should not be used.