Water thermostat: install with spring up or spring down on vintage mercruiser I/O?

[redgoat]

I have a vintage '67 I/O with a 120 hp Mercruiser engine that is a 2.5L 153 cu.in. 4cyl design. I think I may have installed my water thermostat incorrectly over the years and am now determined to install it correctly, if previously it was wrong. The thermostat will "fit" into the engine hole either way. My question is does the spring go DOWN into this hole that is close to the manifold or does the spring go UP into a cast iron bolt down "cap"? With all the specs that I have provided for this 53 year old engine, does anyone know for certain which way the thermostat should be installed?

 

[GA_Boater]

How did you fit it, up or down?

 

[achris]

The wax motor of the thermostat needs to be in the water getting heated...

 

[redgoat]

My question seems simple enough. Does the large thermostat spring go INTO the block, i.e. down, or does the large spring of the thermostat face upwards towards the sky? I would post two photos of my thermostat but they are more than 2 MB and cannot be uploaded. Surely someone out there knows the correct way to install this thermostat. Hey Bondo!

 

[achris]

My question seems simple enough. Does the large thermostat spring go INTO the block, i.e. down, or does the large spring of the thermostat face upwards towards the sky? I would post two photos of my thermostat but they are more than 2 MB and cannot be uploaded. Surely someone out there knows the correct way to install this thermostat. Hey Bondo!

I told you, but you didn't listen! Wax motor (which is the active part that does the opening) goes into the side that has the water that is heating up. I have no idea where this 'spring' is... Use a photo viewing program to reduce the size of the photos and post them.

Chris......

 

[redgoat]

How about this. If the thermostat is installed incorrectly, will the engine overheat?

 

[achris]

I've never installed one upside down, so I can only surmise, probably....

 

[Bt Doctur]

What Chris is trying to say is the active part of a thermostat that open ans closes it goes to the hot coolant side of the engine.In most cases the spring surrounds this element