Thermostat, in or out......

The thermostat plays a critical role in your cooling system, regulating operating temperature.  The thermostat ensures optimum operating temperature is reached prior to opening, sending the hot coolant to the radiator to cool.

When using water in your cooling system the thermostat is a necessary component and without it, engine warm up, and reaching optimum temperature can be compromised.

But remember, when talking about a ‘waterless’ coolant different rules apply. You cannot simply use a waterless engine coolant and apply the same principles as a water-based coolant.  The chemical and physical characteristics couldn’t be further apart.

The decision to remove your thermostat is purely dependant on your cooling system design, and what other restrictions are present in your cooling system.

In previous articles we have addressed ‘flow’, from using a single pass, non restrictive radiator to freeing up pump flow.  The thermostat acts as a restriction, and when using Evans a decision can be made as to whether you keep it in or remove it. 

Firstly, it is not safe to remove the thermostat in all engines.  On most occasions a decent hi-flow thermostat will provide the extra flow needed when using Evans Coolants.  However, most Small & Big Block Chev, Ford and Chrysler Engines can successfully have their thermostats removed. No matter High Performance or stock.  These engines make the removal of the thermostat easier due to the fact that they either have a small internal bypass circuit that does not influence the temperature or an external hose that is easily plugged.

The reason Evans allows thermostat removal has nothing to do with the engine itself. Evans higher boiling point (190C) does not require the restriction (pressure) of the thermostat to work properly. By removing the thermostat the flow volume is maximized with the components already present in the system.

Using Evans can result in slightly warmer coolant temperatures.  The warmer temperatures are generally caused by restriction within the cooling system... pump, radiator, and thermostat. Removing the thermostat brings these temperatures back down to the engines ideal operating temperature, keeping in mind that this also depends on radiator flow/restriction and pump drive ratio.

Over-cooling or not reaching optimum operating temperature is not an issue; Evans will heat up quicker than water-based coolant due to chemical differences. In sub-zero temperatures or during extreme winters it can be an issue and installation of a thermostat may be necessary. When it comes to cooling system design getting heat back into the engine is easy, it's getting it out that's the challenge.

Whether the system will function without the thermostat all depends on the design of the system and the amount of reserve capacity it has. 

When this is done the thermostat bypass should be plugged but some are internal and this can become a difficult task. This is too avoid coolant bypassing the radiator all together. Care must be taken with LS, LT and Modular Ford engines which consist of 2 stage thermostats that have the bypass foot as part of the thermostat and normally the bypass port is as big as the upper hose.

Blower or turbo cars are going to need some type of temperature control to run properly as will a computer controlled system. Removing the thermostat and plugging the bypass can result in the blower or turbo’s being starved of coolant.  A good high flow thermostat will work really well in these engine types.

All cooling systems are different, so some trial and error may be needed to understand what works best for your cooling system.

We are happy to discuss this anytime so if you need advice regarding your particular set up, please don't hesitate to contact us anytime.

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