why would someone cut the thermostat out?

[Lone_Wolf]

So,

I threw a check engine light that indicated that the coolant wasn't reaching operating temp.

So seeing that I bought this truck used, and I don't know the history I decided to replace the thermostat, hoses and coolant.

When I got to the thermostat, all that was installed in the truck was a ring of a former thermostat. Someone had cut the actual thermostat out and just put the metal ring back..

My first thought was, well some idiot just was trying to relieve over heating problems they didn't understand....

But then I thought, well maybe this was some shady used car dealers way to hide some other problem...


So, my real question is why would someone do this??

 

[koda2000]

So,

I threw a check engine light that indicated that the coolant wasn't reaching operating temp.

So seeing that I bought this truck used, and I don't know the history I decided to replace the thermostat, hoses and coolant.

When I got to the thermostat, all that was installed in the truck was a ring of a former thermostat. Someone had cut the actual thermostat out and just put the metal ring back..

My first thought was, well some idiot just was trying to relieve over heating problems they didn't understand....
But then I thought, well maybe this was some shady used car dealers way to hide some other problem...


So, my real question is why would someone do this??

That would be my guess. Or maybe the PO wanted to save $12? Running the engine at less than full operating temp throws a CEL code because you never enter closed loop mode, which really screws up your fuel economy. It's like running a carbureted engine with the choke on.

 

[Lone_Wolf]

some guys at work are saying maybe they were masking a head gasket problem. ie, running the thermostat wide open doesn't allow pressure to build, and thus not pushing coolant through the head gasket....

dont know about that theory...

 

[koda2000]

some guys at work are saying maybe they were masking a head gasket problem. ie, running the thermostat wide open doesn't allow pressure to build, and thus not pushing coolant through the head gasket....

dont know about that theory...

Yeah, I don't know about that theory either. Only way to know is to replace the t-stat and see what happens.

 

[2000StreetRod]

thermostat flow

some guys at work are saying maybe they were masking a head gasket problem. ie, running the thermostat wide open doesn't allow pressure to build, and thus not pushing coolant through the head gasket....

Coolant flows thru the heads (and block) whether the thermostat is open or closed. The closed thermostat blocks flow to the radiator allowing the engine to warm up faster. When the engine is driven a lot at below normal operating temperature sludge rapidly forms.

Once it forms it is difficult to get rid of and if not done carefully can block oil passages when large chunks break free.

 

[Lone_Wolf]

Coolant flows thru the heads (and block) whether the thermostat is open or closed. The closed thermostat blocks flow to the radiator allowing the engine to warm up faster. When the engine is driven a lot at below normal operating temperature sludge rapidly forms.
View attachment 86313
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Once it forms it is difficult to get rid of and if not done carefully can block oil passages when large chunks break free.

Wow! thanks for those pics, that's a great argument for never running sans thermostat.

I installed the thermostat, and I'm just crossing my fingers that there's not a head gasket problem.