loud thermostat

[rustyboltz]

I just flushed and cleaned the cooling system in my 93. While I was at it, I replaced the heater hoses and the thermostat. I have had the truck sitting at a 30 deg angle to burp it now for several days. While it is idiling and the truck is warmed up with the radiator cap installed, I get a loud clicking sound from the front of the engine. I used my stephascope and found out that everytime I hear the coolant moving in the metal thermostat housing, I hear a loud click. The truck in not running hot and I installed it correctly with the hole at 12 o' clock. The thermostt is the same temp as the one I replaced 92 deg C.
Is this thermostt defective?
Should I put the old one back in?
I have never had a thermostat make that much noise. The old one did not do it and am wondering about this one. Any help would be appreciated.

 

[mr cribb]

Well I have never heard of such a thing. How much louder can it be than the v6 engine itself?

Strange coincidence my wife grew up in Paola.

 

[SwaintaN]

might be a faulty tstat, however never heard of this...

 

[Roadrunner777]

Maybe it is thermal expansion of the housing, rather than the thermostat itself. Back off the housing bolts, like 1/16 of a turn and see if it changes. I know generally you don't need any sealant on the housing, but it might address this problem.

 

[FIND]

I'm going to agree with roadrunner here. That would be the first thing I tried.

 

[rustyboltz]

It's not really loud while the vehicle is running, but once I turn it off it makes 2 really loud clinking sounds. While it is running tho, it can be heard but not very loud. I have been thinking about this and the only difference between the 2 thermostats is there was a floating ball in a cage over the hole in the old stat and the new one had just a small hole there with no floating ball check valve. Would that make it make the noise? Like maybe cold coolant going into the engine too fast too often?

 

[Jason94sport]

While not on a X I have heard the tstat opening & closing with a click before. What brand tstat is it?

 

[FIND]

No, that sound is definitely thermal expansion. It happens in some vehicles and doesn't in others. It is probably not even happening right where you are observing it with your scope either. The thermostat housing just provides good resonance and amplifies the sound for you, so it seems like that is where it is coming from.

Do not worry, it is a normal sound.

 

[rustyboltz]

I am going to do what was suggested and back off the bolts apprfox 1/16 turn to see if that helps. The only problem with that is that I need to remove the tensioner to get to it.

 

[Roadrunner777]

The bolt at 10'oclock is a tough reach, I got it with 1/4" x 10mm short socket, universal, and a long extension. I actually ended up going out to buy the universal... forgot I broke it recently. But, you might be able to get the box end of a combination wrench in there... 1/16 turn isn't much. Really, if you could do 2 out of 3, you should notice a difference.

 

[SwaintaN]

i take off the tension pulley to get to that one, makes it ton easier.

 

[Roadrunner777]

Yup, that too. I forget sometimes how easy it is to get the belt off this engine. Every other one I worked with in the past was 2 guys and a dog... but they were transverse engines.

 

[rustyboltz]

I loosened 2 of the bolts approx 1/6 of a turn and it definately made it not as loud. i think I will drive it like this all winter and see how it acts.

 

[SwaintaN]

yeah this belt is way easy to do, even easier with no a/c pulley