Frequently Asked Questions
Click on a question to view the answer.
My engine never gets hot but it looks like the thermostat does not open. Why is this?

This can be normal but only if the engine is not getting hot. Most likely your cooling system is very efficient. The faster the radiator dissipates the heat to the air the less water has to flow through the radiator to keep the engine at the operating temperature of the thermostat. If only a small amount of water flow is needed to keep the engine at this temperature you will only see the index pointer move a very small amount.

Can Cool-View help me determine the efficiency of my cooling system?

Yes, it can be a very good tool to help determine the efficiency of your cooling system. Here is how it can help. The cooling system is comprised of several main parts that have to work together for your engine to run at any given temperature. Without getting into BTUs, thermal conductivity, and other technical stuff, here are the basics of what you need to know to make some simple determinations about the efficiency of your cooling system.

First, the main parts of the cooling system are the engine cooling jacket, the water pump, the thermostat, the radiator hoses, the radiator, and in most case the radiator fan and shroud. How far open or closed the thermostat runs under normal operating conditions both cold and hot weather is a good indication of how efficient your cooling system is. Cooling systems are designed so the thermostat runs less than half way open under normal conditions at moderate temperatures so that when the ambient temperature increases the thermostat can open farther and still increase the flow resulting in more cooling. In order to do this the cooling system has to be able to dissipate more heat than the engine produces with the thermostat less than half way open at moderate ambient temperatures. The less efficient any of the cooling system parts are, the farther open the thermostat will run. If you are working on a hot rod or muscle car this can be a big help as you can see changes to efficiency as you make modifications to the cooling system.

How strong is the glass?

The glass tube is made out of borosilicate glass commonly known as PYREX®. With its pressure, temperature ratings, and its thermo expansion coefficient this glass is ideal for this application. This type of glass is used for sight glass tubes on boiler systems. The thick walled glass used on the Cool-View unit can withstand 150PSI at 500°F.

What happens if I need to replace the thermostat in my Cool-View unit?

We have you covered two ways. Buy one from us or purchase the correct thermostat from any NAPA ® store. It is not necessary to purchase a whole new assembly from us if you only need a new thermostat. We wouldn’t stop you from doing that, but it is not necessary. The standard replacement thermostats are NAPA ® part number THM 139 for the 180°F thermostat and part number THM 239 for the 195°F thermostat. We also have instructions to reuse the index pointer.

Can I run straight water?
Yes, this is not a problem. If you intend to run only water we recommend using the stainless steel collar upgraded version of our thermostat.
Can I use the Cool-View unit without a thermostat?
Yes we sell a Cool-View unit that does not have index lines just for that reason. You can also use restrictor plates with it. Note: Running a street engine without a thermostat is not recommended.
Will I need to change the length of my radiator hose?
Probably not. In most cases there is enough flexibility to just move it up to the new location. You may however want to shorten the hose in some cases just to make it look better.
Will the Cool-View units fit on non-specified engines?
In some cases. The Chevy version of the Cool-View unit is designed to be used on non-bypass cooling systems of small and big block Chevy V8 engines. It will fit other engines with the same thermostat housing mounting dimensions. Check out this drawing of the mounting size so you can determine if the Chevy version of the Cool-View unit will fit your engine. » Download Diagram (PDF)
What kind of coolant can I use?

The Cool-View unit is compatible with any standard engine coolant. Make sure the type of coolant you use is compatible with all of the components in your cooling system and or your engine’s OEM specifications. Check out this article at Popular Mechanics. It is well worth the read if you intend to use one of the newer extended life coolants in an engine with a brass copper radiator or heater core. For more information, check out Popular Mechanics page on coolant.

Is there a warranty?

Yes! For more on this visit the warranty page.