[shommel]

1965 gt fastback 289 4v A code .brand new 160 thermostat(that works) new water pump(works fine) all hoses ok but still running hot. any ideas?

[Calponycarsmike]

Did you check the temp sending unit? Also you could have an air bubble in the system it is hard to do in these old cars, but it can happen.

[shommel]

where is the temp sending unit located?

[gene111]

We have issues all the time with people changing out the thermostat & it still runs hot 90% of the time it is air bubbles. try putting a funnel in the radiator fill with coolant & let car run for a while. Sometimes giving the car gas while doing this helps.That should work the air out .

[Calponycarsmike]

Temp Sending Unit should be on your manifold.. do you have a shop manual???

[Little Mule]

Have you also done a really good engine flush? my 289 was the same way and it took me flushing the engine 3 times before a clump of - umm... sludge? - just fell out. Never had a problem since.

[PaulS]

While you are revving your engine watch the lower radiator hose. If it starts to flatten then you need to get a wire coil that goes inside it to keep it from colapsing.

[snaranjo]

Try bumping the thermostat to 180. With a 160 you may not be allowing the water to stay in the radiator long enough to actually cool off. It is a misconception that a lower thermostat temp will allow the car to run cooler.