5 Coolants 5.1 General information Coolant definition Coolant
= coolant additive (concentrate) + freshwater to predefined mixing ratio ready for use in engine.
The corrosion-inhibiting effect of coolant is only ensured with the coolant circuit fully filled. The only exception is Oil 9156, which maintains its corrosion-inhibiting character even when the coolant was drained due to oil-film formation in the circuit. Apart from that, only the corrosion inhibitors approved for internal preservation of the coolant circuit provide proper corrosion protection when the medium was drained. This means that after draining the coolant the cooling circuit must be preserved if no more coolant is to be filled. For the preservation procedure, refer to the MTU Preservation and Represervation Specifications A001070/.. of the engine. Coolants must be prepared from suitable fresh water and an MTU-approved coolant additive. Conditioning of the coolant takes place outside the engine. Mixtures of various coolant additives and supplementary additives (also in coolant filters and filters downstream of plant components) are not permitted! The conditions for the approval of coolant additives are specified in the following MTU works standards (MTL): • MTL 5047: Emulsifiable corrosion-inhibiting oils • MTL 5048: Corrosion-inhibiting antifreeze • MTL 5049: Water-soluble corrosion inhibitors Coolant manufacturers are informed in writing if their product is approved by MTU.
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To prevent cooling system damage: • When topping up (following loss of coolant) it must be ensured that not only water but also concentrate is added. The specified antifreeze and/or corrosion inhibitor concentration must be maintained. • The corrosion inhibitor concentration must not exceed 55 % by volume (max. antifreeze protection). Concentrations in excess of this reduce antifreeze protection and heat dissipation. Only exception: BASF G206 (special application) • The coolant must not contain any oil or copper residue (in solid or dissolved form). • The majority of corrosion inhibitors currently approved for internal coolant circuit preservation are watersoluble and do not provide antifreeze protection. Make sure that the engine is stored safe from frost, because a certain amount of coolant remains in the engine after draining. • A coolant circuit can not usually be drained completely, i.e. residual quantities of used coolant or freshwater from a flushing procedure remain in the engine. These residual quantities can result in the dilution of a coolant to be filled (mixed from a concentrate or use of a ready mixture). This dilution effect is higher the more add-on components there are on the engine. Check the coolant concentration in the coolant circuit and adapt it if necessary. All coolants approved in these Fluids and Lubricants Specifications generally relate only to the coolant circuit of MTU engines. In the case of complete propulsion plants, the operating fluids approvals of the component manufacturer must be observed! For corrosion-related reasons, it is not permissible to operate an engine with pure water without the addition of an approve corrosion inhibitor!
A001061/37E 2016-12 | Coolants | 23
