Protege L4-1839cc 1.8L DOHC (1990)
1.
Check the punch mark numbers on the cylinder head to determine production date. If the numbers read 8-1-1 or later, the cylinder head was
manufactured using a modified machining process and does not require further inspection. Figure 2.
2.
If the punch mark indicates a production date prior to August 1, 1991, remove the thermostat according to procedures in the Workshop Manual.