Blown head gasket thermostat?

[DARTHSHO]

so I just took the thermostat out of the car because the dealership said it stuck closed and caused the head gasket to blow. The problem is the thermostat in there was a fail safe motorad one literally can’t get stuck closed. So now the issue is what caused it. And why is it overheating. Just another discovery in owning my SHO

 

[yaycandy]

Dont they need oriented correctly with the jiggle valve up or something? Or is that just a myth.
Quick internet search shows many failures for stuck closed on multiple types of vehicles with that thermostat.
No such thing as a fail safe thermostat, it would just have a lower failure rate or a higher fail rate because it jynxed itself

 

[802SHO]

I thought there was such a thing. On my GF’s 14 Jeep Grand Cherokee they say the thermostat will fail open and thus it still protects the engine. We thought maybe she needed one, it threw a code for it but the fluid was extremely low, just from filling it back up after 3 days of drive cycles it cleared itself and the level is holding, so don’t think it’s leaking either. Honestly I think the garage we brought it to a sabotaged it....bc I had recently did the brakes and oil change and topped off all her fluids, only thing I needed to top off was windshield washer fluid....then shortly after we got it back the radiator fluid was bone dry? Yeah....nice try shitbags!

 

[luigisho]

Dont they need oriented correctly with the jiggle valve up or something? Or is that just a myth.

That's correct as far as my replacement memory goes. I think there may be more than 1 design and the jiggle valve one is preferred and valves up.

 

[yaycandy]

That's correct as far as my replacement memory goes. I think there may be more than 1 design and the jiggle valve one is preferred and valves up.

I never really thought about it but how does the jiggle work. Does it let coolant through in the event of a closed thermostat? Does it allow air bubbles to move up when in closed operation when cold?

 

[luigisho]

I think it might be for gas pressure. Probably allows for some coolant too but the openings are very small. Not like a wide open larger valve. I keep forgetting sometimes I'm posting in the newer car section. My previous post is in regards to the older cars. Here is a rando google pic of an example. I forget if the ones I used had 1 or 2 of those little jiggle valves on it.