Coolant flow through thermostat during flush?

[Hoye0017]

Hi everyone,
I'm in the middle of a Timing belt/water pump change and something's happening I didn't expect:

I installed my brand new water pump and thermostat with new thermostat gasket (all OEM parts). I opened the block drain and poured distilled water down the upper radiator hose.

I expected to see the water only through the block drain, but it was also coming out of the thermostat lower outlet.

Is that right? I thought the thermostat would be keeping the water in. Sorry if this is a stupid question. I haven't done this level of wrenching in quite a while.

 

[Bstrom]

Was there a weep hole or bypass in the thermostat? Is it a strong flow or just a trickle? You are right that the flow should be restricted but not plugged as the thermostat allows some flow to maintain volume while it warms up.

Someone else confirm my suspicions as I have never done this service work.

 

[Hoye0017]

It wasn't coming as fast as I was pouring. After disassembling again, I think it's just what the juggler was letting through.

 

[Hoye0017]

*jiggler. Dumb auto-correct.

 

[Bstrom]

*jiggler. Dumb auto-correct.

Jiggler? Not bypass valve? There are correct names for these things! Just kidding...I like jiggler too. Ha!