Davies, Craig For Your Overheating Small Block Chevrolet

17/01/2020 12:00AM

Chevrolet’s small block V8 engines are known for their strength and durability. But like anything mechanical, Small Block Chev overheating issues can occur and it can sometimes be a matter of following a path from a to z to identify the cause of SBC overheating problems. The most easily recognised indicator? Keep an eye on the car’s temperature gauge.

There are typically four common Small Block Chev Overheating Problems.


A critical part of a car’s cooling system, particularly in cars now considered to be vintage, is the thermostat. A general design feature is of a disc in a housing, and as an engine’s mechanical heat warms the coolant in the cooling system, a material, most likely a form of wax, will liquefy and move a small cylindrical rod. This rod’s movement opens a plate that would block fluid flow through a radiator and then allow that flow to run through the vanes of the radiator and use passing air to cool.

A common SBC overheating issue is the failure of these heat activated mechanical parts which leads to a lack of coolant being circulated for heat exchange. As a rule, these parts are easily replaced and can make an instant difference in respect to fixing a SBC overheating issue.

A Davies Craig  LCD EWP®/Fan Digital Controller can be a more viable alternative. Mechanical thermostats are effectively preset to activate at one temperature. A Davies Craig LCD EWP®/Fan Digital Controller can be preset to allow flow at up to five different temperatures, meaning more flexibility and allowing a tailor-made application depending on engine size and usage.


Depending on the capacity of the SBC, a radiator, or heat exchanger, may be of a smallish size or it could be quite broad. The size provides a certain surface area to airflow, meaning the larger the size then naturally a larger area exposed to the air. However this can also be detrimental.

A common SBC overheating issue is airflow over the radiator being blocked by a number of materials. Dirt, dust, leaves, and even insects that pass through a car’s front grille will get stuck on the vanes and thin metal plates that make up a radiator’s design. Because airflow is disrupted, and the metal itself isn’t directly in contact with the air, the temperature differential changes and the thermal efficiency decreases. As a result, a SBC overheating issue can occur.

Spray-on degreaser, a stiff brush, and a pressure hose should be sufficient to clean the radiator and allow for proper airflow. This should be enough to address this particular SBC overheating problem.

A Davies Craig Thermatic® fan can also assist. Available in different sizes and with the flexibility to be mounted on the front (to push air through) or the rear (to pull air through) a radiator, these high-efficiency units can potentially overcome any form of airflow problem for a dirty radiator.

Air to fuel mixture

This is one for the older SBC overheating problem book. Oddly enough, fuel can be considered a cooling component even though its main purpose is to be ignited and used to provide power. Older cars using “carbies” are more prone to overheating thanks to fuel and air mix matters and SBC overheating issues are no different.

Although a throttle cable moves an actuator on a carbie that releases more fuel through the venture and into the cylinders, wear and tear can see the mechanical parts incorrectly deliver fuel.

As a result, a “lean” mixture, where there isn’t enough fuel vapour in relation to the air in the cylinder, will burn hotter and can lead to cylinder damage. Think of a hot day where a hose with a mist attachment is turned on. A low flow makes little difference but a higher flow of water, making more mist, makes for a cooler localized air temperature.

This is effectively the same as what can happen inside a cylinder and overheating from an incorrect fuel to air delivery mix can be a common cause of SBC overheating issues.

Water pumps

Mechanically driven water pumps rely on the rotation of the engine to spin a pulley that rotates an impeller to move coolant. In order to move coolant efficiently the engine needs to be moving all the time and at a good rate of revolutions per minute.

This is an immediate downside in a mechanical sense as slow or stopped traffic means the engine’s rotational speed is low, and therefore moving the mechanical impeller not very much at all. Heavy traffic situations also mean little to no airflow through the radiator.

An Electric Water Pump, or EWP®, from Davies Craig is an immediate solution to the limitations of a mechanical water pump. Many SBC overheating issues can be alleviated by the fitment of an EWP®, as they can be more energy efficient by not sapping mechanical energy and can be set to activate independent of an engine’s working nature.

This means they can pump fluid independently of an engine’s revolutions and can be programmed, via a digital controller, to move coolant even after an engine has been switched off.

And because they can flow at rates of up to 150L per minute, instead of a limited flow rate from a mechanical pump, a Davies Craig EWP® (and in conjunction with an LCD EWP®/Fan Digital Controller and Thermatic® fan) is effectively a complete solution to a SBC overheating issue.

www.daviescraig.com.au is the one stop online shop for your extra cooling needs. Have you had overheating issues with your SBC? What did you do to overcome them? Let us know your story via our social media outlets and here on our blog.