Silica gel formation in heavy duty diesel cooling systems has increased with the increased usage of antifreeze with high levels of silicate. Gelation can occur when this type of antifreeze is mixed with supplemental coolant additives which are required to protect heavy duty diesel engine cooling systems, or when the undiluted antifreeze is stored for long periods. Gel in the cooling system can decrease coolant flow and heat transfer causing engine overheating.
Gel formation is shown to be a chemical problem, not a problem of newer engine and cooling system design. Recommendations for avoiding the problem are included.