ISO INTERNATIONAL 9818 STANDARD First edition 1991-12-15 Passenger cars -- Engine cooling systems Test methods and marking of pressure caps Voitures particulieres -- Systemes de refroidissement des moteurs Methodes d'essai et marquage des soupapes de surpression/depression Reference number ISO 9818:1991(E) Not for Resale without license from IHS ISO 9818:1991(E) Foreword iso (the International Organization for Standardization) is a woridwide federation of national standards bodies (IsO member bodies). The work of preparing International Standards is normally carried out through IsO technica! committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, govern- work. isO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are national Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard isO 9818 was prepared by Technical Committee ISO/TC 22, Road vehicles, Sub-Committee SC 24, Interchangeability of components of passenger cars. iso 9818 forms one of a series, consisting of the following International Standards: Iso 9133:1988, Passenger cars - Engine cooling systems - Threaded pressure caps and their seats on filler necks. Iso 9817:1991, Passenger cars -- Engine cooling systems --- Dimen- sions of pressure caps and their ramp seats on filler necks. Iso 9818:1991, Passenger cars - Engine cooling systems - Test methods and marking of pressure caps. Annex A forms an integral part of this Internationai Standard. C 1SO 1991 Afl rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, Including photocopying and mlcrofllm, without permisston in writing from the publisher. Internatlonal Organization for Standardization Case Postale 56·CH-1211 Genéve 20·Switzerland Printed in Switzerland Not for Resale se from IHS INTERNATIONAL STANDARD ISO 9818:1991(E) Passenger cars -- Engine cooling systems -- Test methods and marking of pressure caps The number of such operations shall be defined by Scope 1 common agreement between the cap manufacturer and the user. This International Standard specifies test methods and a marking system for pressure caps for use in engine cooling systems of passenger cars. 2.3.2 Endurance test under alternate pressure 2 Test method Cycles .of alternate pressure, consisting of a suc- For the test given in 2.1 and for residual pressure cession of injections of pressurized air into a test measurement as described in 2.2, the standard filler liquid composed mainly of 50 % ethylene' glycol solution, shall be applied to the cap according to seat with clamping ramps as described in annex A figure 1. shall be used. 2.1 Valve opening test under pressure and ressure, bar depression This test shafl be carried out at room temperature. The valve opening pressure shall be the pressure for which a constant leak rate of 30 cm"/min is ob- tained. A microleak of 100 cm/h is permitted before the valve opens itself. 2.2 Residual pressure for seats with clamping ramps 10 20 TIme, s The residual pressure shall be measured at room Pa : afmospheric pressure temperature. P1 : 1z0 % of the opening pressure The pressure inside the filler neck shall be meas- NOTE -- The shape of the curve is given for information ured after pressufe stabilization, with the cap pawls only. in position in the ramp decompression notch (di- mension l). Figure 1 2.3Endurance tests The test liquid temperature, defined by agreement 2.3.1 Fitting and removing caps from seat between the cap manufacturer and the user, shall be equal to or greater than 80 'C. This test consists in the cap being fitted on, and re- The pressure valve seal shall be in contact with the moved from, the fille