Mechanical and plant engineering

Coolants in stationary gas engines – Tectrol takes full advantage of analytics

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The Tectrol brand stands for high-quality lubricants for almost all applications. Its core competencies include lubrication and cooling of stationary gas engines that generate energy in CHP plants. As a technological pioneer, Tectrol recognised at an early stage that high-performance gas engine oils can achieve successful results only in combination with oil analyses. Now it is also leading the way when it comes to monitoring the coolants of these gas engines. After all, it has become clear over the years that the cause of around 15% of all defects in gas engines can be found in their cooling systems. Tectrol and OELCHECK have therefore also maintained a long-standing cooperation in the field of coolant analysis.

Tectrol MethaFlex gas engine oils offer the best protection for combined heat and power plant (CHP) gas engines even in long-term use. Over 4,000 CHP engines powered by natural, bio or special gases use one of the more than ten Tectrol gas engine oil types. Together, the engines achieve over 30 million operating hours per year! 

Tectrol has developed the Coolprotect range of coolants tailored to the requirements of the engines and the properties of Tectrol MethaFlexx gas engine oils. Ready-mix products were created in particular to permit simple and safe use.

The cooling system as a source of danger

Around 15 % of all faults in CHP systems have their starting point in the cooling system. However, the importance of the coolants was often underestimated or the handling of the fluids was not carried out correctly. Modern coolants are high-tech products on which the reliable performance of the cooling system and engine depends. Above all, they must continuously dissipate the heat from the engine, because this must be operated with only slight temperature fluctuations. A constant flow rate that is not affected by deposits or air inclusions is essential for this. The active ingredients added to the agents must reliably prevent corrosion, erosion, cavitation, foaming and any kind of deposits. 

Good compatibility with all installed components is a matter of course. The additives must protect the various metal alloys, elastomers and plastics installed in engines, cooling hoses, seals and in the expansion tank over the entire service life of the engine. If heat is not dissipated from thermally loaded engine components, the gas engine oil is subjected to even higher demands. In most cases, its temperature load increases and the oil ages more quickly. Its viscosity and thus its lubrication performance decrease. Overall, the service life of the oil is shortened and the oil must be replaced sooner.

Safe and fast with ready-mix

Coolant concentrates are mixed with water before use. But tap water is often not suitable for this. Engine manufacturers specify accurate values for total hardness, electrical conductivity and the calcium or chloride content of the make-up water. Failure to comply with these specifications can lead to malfunctions in the cooling circuit. However, preparation of make-up water that meets specifications often poses major challenges for users.

Tectrol has the perfect solution for this: ready-mix coolant from the Tectrol Coolprotect-Mix series! The products are pre-mixed with specified make-up water and can be used immediately. Tectrol Coolprotect Mix is approved by leading engine manufacturers and offers the certainty that the mixture is correct. The excellent product properties enable extended coolant change intervals and protect against deposits, cavitation, foam and corrosion. The volume flow is not restricted, the engine is optimally cooled and the cooling system remains clean. 

A pioneer in coolant analytics

Tectrol began to very intensive work on coolant analysis as early as 2013. The challenges were not necessarily to determine individual values, but rather to define an analysis scope that was manageable for all users while at the same time allowing meaningful diagnosis. It also seemed difficult to find a laboratory for this type of water analysis at first. The solution was obvious: OELCHECK was already the proven partner for oil analyses and was already focused on coolant analysis back then. After intensive exchange with leading engine and coolant manufacturers, OELCHECK presented the groundbreaking analysis kits for coolants at the beginning of 2017.

Tectrol: Analyses every 2,000 operating hours

OELCHECK universal kits for gas engines enable analysis of engine oils and coolants. Tectrol uses the universal kits in a targeted way. Customers order the kits conveniently from Tectrol and send the samples to OELCHECK for analysis. The laboratory reports are first sent with an initial diagnosis to the responsible employees in the Tectrol application engineering department. As they are familiar with the plants and the local operating conditions, their many years of experience are included in a concluding comment. This means that customers receive particularly individual and accurate diagnoses.

As in the assessment of oil analyses, the interrelationships of the values determined for coolants are considered. The focus is on the remaining performance potential of the coolant and any indications of damage in the cooling system. However the limit values for the respective assessment criteria are a particular challenge for diagnosis. Many engine manufacturers have so far published no or very few limit values for used coolants. For this reason, OELCHECK and Tectrol have defined limit values based on their own experience and the existing broad database.


Thanks to continuous trend monitoring, Tectrol was able to detect a number of system faults early on and recommend remedial measures to the user. However, the specified change intervals of coolants remain a critical topic. It is risky to simply replace them at regular intervals of one to three years without further consideration. Since operating conditions and coolants can change very quickly in some cases during use, well-known gas engine manufacturers already require short-term changes after 2,000 operating hours (max. 6 months) due to prematurely reached limit values. 


Tectrol generally advises coolant analyses after a maximum of 2,000 operating hours. Replacement is usually not recommended until the analysis values exceed or fall below limit values. With a preceding flushing process and the subsequent use of the ready-mix product from the Tectrol Coolprotect Mix series, this process can be completed without long interruptions in operation.

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