The increased use of aluminum in automobile engines has led to new requirements for engine coolants to prevent aluminum corrosion. Increasing the level of silicate corrosion inhibitor in the engine coolant has been the most common method of providing the additional aluminum protection. However, these higher silicate levels have led to problems in heavy duty diesel engines, where supplemental inhibitor packages are used. Many diesel engine manufacturers now limit the silicate levels that can be used. This means that two types of engine coolants are now needed - high silicate to protect aluminum automobile engines, and low silicate for heavy duty applications. Salts of dibasic acids have been studied as corrosion inhibitors; however, generally they are too expensive to be used in engine coolants. A commercially available mixture of dibasic acids was evaluated in engine coolant formulations, and a potential formulation was developed. The silicate level is low enough to be used in heavy duty applications, and yet excellent aluminum inhibition is obtained. This formulation has an additive cost similar to that of current engine coolants.

Subject
Acids, Costs, Composition, Aluminum, Silicates, Coolants, Mixtures, Phosphates, Engines, Sodium, Metals, Corrosion inhibitors, Corrosion protection
© 1988 Association for Materials Protection and Performance (AMPP). All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording, or otherwise) without the prior written permission of AMPP. Positions and opinions advanced in this work are those of the author(s) and not necessarily those of AMPP. Responsibility for the content of the work lies solely with the author(s).
1988
Association for Materials Protection and Performance (AMPP)
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