1982 124 Spider Two Thermostat question

[vanover69]

Im in the process of replacing my timing belt, water pump, and the broken bolts I caused on my journey
In the parts I ordered I received two thermostats, an internal and a external.
When I removed the upper thermostat housing there was no thermostat installed
Questions:
1. Did these cars come with two thermostats?
2. Do I need two thermostats
3. I see some people drill a hole in the lower thermostat?
- Is this to help with bleeding the system?
- Any photos someone can share?
Thanks in advance
Rob

[tima01864]

The later models only use the external thermostat. It does have an orientation.
On my early Spider I had problems bleeding the engine, But on my 83 I followed the manuals instructions exactly, Filling slowly, Have had no issues with air in the system.

[RRoller123]

Some folks do drill a small hole in the tstat plate to allow air to pass and ease filling, but it is a bad idea, and not necessary. The orientation of the external tstat can be confusing, but the general way to look at it is that the side stub goes over to the water pump.

[vanover69]

Thanks for the info
Before posting this question I had already installed the upper t-stat

The new question is
Should I take it out now?

Thanks
Rob

[SteinOnkel]

Yes, the external thermostats flow more. And these cars don't have the biggest radiators in the world so you want all the flow you can get.

[Nut124]

Yes, there should be no thermostat under the coolant outlet from the head. The external therm always circulates coolant thry the head and block keeping head temp uniform. Head gasket tends to blow with an internal therm.

The orientation is as follows:
The port that is closed at room temp goes to bottom of radiator. The port that is always open goes towards the pump. The port that is open at room temp, but closed when hot goes to the outlet T.

The picture posted above matches my installation but I'm not sure all ext therm housings are identical.

[wetminkey]

Guess what kind of disaster occurs when your car comes with BOTH thermostats in place?!!

[vanover69]

Thanks for all the comments and help

I have removed the top thermostat.
Next item is to swap the timing belt...install new water pump and finally the radiator

Thinking Im going to flush the radiator prior to installing

Can wait for summer
Robert