Thermostat

[Edgey]

1977 Fiat 124 spider has an external thermostat. Would it also have an internal thermostat in the engine block?

[18Fiatsandcounting]

No. It has one or the other, but not both. There have been cases where owners have tried to install both, but that's not correct. My recollection is that the 1438s had internal thermostats, the 1608 was external, the 1592 went briefly back to internal, then the 1800 starting in late 1973 was external. 2L are external as well.

By the way, the internal thermostat is in the top front of the cylinder head, beneath the top outlet for the coolant hose.

-Bryan

[Edgey]

Thank you, that makes sense. I will re & re the external thermostat and not take out any bolts that don't need to be removed.

[Nut124]

When you replace the thermostat, pay close attention to correct orientation of the ports. The replacement may look similar but can have different port assignments.

The port that is closed goes to btm of the radiator. Port that is open goes to the T at the head. One that can never close goes to the water pump.