KENYA STANDARD      DKS  251:2020  
ICS 43.060.30  
 
 
 
 
 
 
 
 
 
 
 
Motor vehicle radiators  — Specification  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
No copying of this standard without KEBS permission except as permitted by copyright law  
 
 
 
 
 
 
 
         
    
   
TECHNICAL COMMITTEE REPRESENTA TION  
 
The following organizations were represented on the Technical Committee:  
Toyota Kenya Ltd  
D.T Dobie  
Mitsumoto  
Isuzu E.A  
Kenya Association of Bus Manufacturers (KABM)  
Kenya Motor Repairers Association (KEMRA)  
Nissan  
Numerical Machining Complex (NMC)  
Gede Enterprises  
Mobius Motors  
KUMPIA  
Kenya Industrial Research and development Institute (KIRDI)  
Technical University of Kenya (TUK)  
Motorwise Valuers  
Kenya Auto Bazaar Association  
Honda (Nairobi)  
Egerton University  
Olive Technical Services Ltd  
Kenya Jua K ali Association  
MCI Ltd  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
REVISION OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions for 
improvements to published standards, addressed t o the Managing Director, Kenya Bureau of Standards, are 
welcome.  
 
 
 
 
 
 
© Kenya Bureau of Standards, 2020  
Copyright. Users are reminded that by virtue of section 25 of the Copyright Act, Cap. 12 of 2001 of the laws of Kenya, copyri ght subsists in 
all Kenya Standards and except as provided under section 26 of this act, no Kenya Standard produced by Kenya Bureau of Standards may 
be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in writing from the Mana ging 
Director.  
 
 
 
 
 
 
 
 
 
 
 ©KEBS       KS 06 -251:1982      
      
   
ISBN 9966 -782-13-3 
 
KENYA STANDARD         DKS  251:2020 
ICS 43.060.30  
 
 
 
 
 
 
 
 
Motor vehicle radiators — Specification  
 
 
 
 
 
 
 
 
KENYA BUREAU OF STANDARDS (KEBS)  
 
Head Office:  P.O. Box 54974, Nairobi -00200, Tel.: (+254 020) 605490, 602350, Fax: (+254 020) 604031  
E-Mail: info@kebs.org,  Web:http://www.kebs.org  
 
Coast Region     Lake Region          Rift Valley Region  
P.O. Box 99376, Mombasa -80100   P.O. Box 2949, Kisumu -40100        P.O. Box 2138, Nakuru -20100  
Tel.: (+254 041) 229563, 230 939/40                Tel.: (+254 057) 23549, 22396        Tel.: (+254 051) 210553, 210555  
Fax: (+254 041) 229448    Fax: (+254 057) 21814  
  
 
 
 
 
 
 
 
 
 
 
  DKS 251:2020  ©KEBS  
2  Foreword  
 
 
A vehicle radiator as a heat exchanger is an important part of a vehicle. The effects of failure  to dissipate heat 
can be disastrous, therefore radiators are considered to be a critical part  of a vehicle construction. This 
standard, therefore, lays down the requirements considered necessary to produce radiators suitable for use in 
Kenya.  
 
In the prep aration of this standard, reference was made to the following documents : 
 
IS 7611  — Specification for automotive radiators — Copper brass core construction . 
 
IS 3331 — Specification for copper and brass strips/ foils for radiator cores.  
 
Assistance received  from these sources is hereby acknowledged.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
                3  
KENYA STANDARD  
 
SPECIFICATION FOR MOTOR VEHICLE RADIATORS  
 
 
1. SCOPE  
 
This Kenya Standard covers the general requirements and methods of test for automotive radia tors 
manufactured from copper and brass with brackets of steel for use on motor cars, trucks, tractors and 
off-the road vehicles such as earth moving machinery. Radiators utilizing bolted or cast header tanks 
are excluded.  
 
It does not apply to radiators  made of aluminium and plastics  
 
2. DEFINITIONS  
  
 For the purposes of this standard, the following definitions shall apply:   
 
2.1 radiator  — A device used for the cooling of an engine of a motor vehicle which uses water as the 
cooling media which in turn is  cooled by air blown through the radiator fins as the water passes through 
the radiator tubes.  
 
2.2 general — Various parts  of the radiator shall be as shown in Figure 3.  
 
  
3. TYPES    
 
 Two types of radiators shall be considered, namely:  
 
(i) Flat fin core as  shown in Figure 1;  
 
(ii) Corrugated fin core as shown in Figure 2 . 
 
The typical construction of a radiator is shown in Figure 3. However,  pressure relief/filler cap may be 
located on a separate header tank remote from the radiator.  
 
 
4. MATERIAL REQUIREMENTS  
 
4.1 The various parts of the radiator shall be manufactured from material as shown in Ta ble 1.  
 
TABLE 1. MATERIAL RADIATORS  
 
ITEM  MATERIAL  HARDNESS  
Tubes  
Flat Fins  
Corrugated Pins  
Header Plates  
Header Tanks  
Branches  
Brackets  Brass  
Copper  
Copper  
Brass  
Brass  
Brass 
Brass  90/110/VPN  
100/115 VPN  
80/110 VPN  
90/110 VPN  
Drawing quality  
Quarter hard-seamless  
Mild of drawing quality  
 
The material for the tubes shall be 100 per cent inspected pinholes. The surface of the material shall 
be free from contamination which c an prevent satisfactory wetting and bonding of soldier joints under 
normal production conditions.  It shall also be free from oxides, pinholes, blisters, flakes scratches and 
other such defects.  DKS 251:2020  ©KEBS  
4   
The fin shall have sufficient face strength to prevent defor mation in normal handling.  
 
4.2 The steel for the production of brackets and frames shall be cold rolled and of suitable quality to allow 
forming without cracking and to avoid failure due to vibration. Such sheet shall be protected  against 
corrosion by an acceptable method such as terne coating, phosphating, etc.  The steel shall be free 
from defects such as scale, rust, blisters and laminations.  
 
4.3 Solder  — Soft solder shall be used for joining the various parts of a radiator. Soft solder shall be made 
from virgin metal or clean scrap. The material shall be of uniform quality, clean and free from foreign 
matter.  
 
4.4 The chemical composition shall be as show in Table 2.  
 
TABLE 2. COPPER CONTENT IN THE COPPER/BRASS STRIPS  
 
STRIP  COPPER CONTENT , 
PERCENTAGE  
Copper 
Brass  98.0 (minimum)  
61.5 ( minimum)  
71.5 (maximum)  
 
 
5. DIMENSIONS  
 
5.1 Radiators  — The dimensions of radiators shall vary according to engine manufacture specifications.   
 
5.2    Filler Neck — Small and medium size filler necks shall be as in Figure 4.  
 
5.3 Drain Tap Seat — A good tank quality  draining arrangement shall be provided on the bottom tank.  
 
 
6. WORKMANSHIP AND FINISH  
 
The radiator core assemblies shall be pickled to remove flux residues after soldering operations have 
been completed.  
 
The radiator sha ll be free from physical defects. Joints on radiator cores  and water inlet and outlet shall 
have no discontinuity and the soldering material shall be evenly distributed throughout. The inside of 
the filler neck shall be free from solder, paint, cracks and scratches. A suitable protective paint shall be 
used on radiators.  
 
 
 
  
                5  
 
FIGURE 1 — FLAT FIN CORE (TYPE)  
 
 
 
 
 
 
 
FIGURE 2 —  CORRUGATED FIN CORE (TYPE)  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
DKS 251:2020  ©KEBS  
6   
 
 
 
 
FIGURE 3 — TYPICAL ARRANGEMENT OF RADIATOR SHOWING NOMENCLATURE  
 
 
 
 
 
 
 
 
                7  
 
(Dimensions marked * are to suit  pressure relief/filler cap .) 
 
FIGURE 4 — FILLER NECKS  
 
 
 
7. TEST S 
 
 The following tests shall be carried out on the rad iators:  
(i) Pressure test;  
(ii) Vibration test;  
(iii) Leakage test for filler neck seat;  
(iv) Pulsation test.  
 
 
7.1 Pressure Test — This test shall be carried out on every radiator produced  for m ethod of test, see 
Appendix A.  
 
7.2    Vibration Test — This test shall be carried ou t on samples from new model production  to prove the 
durability of design. It shall also be carried out  as a spot check at least one in every 500 units of same 
type produced.  
 
NOTE:  This test is regarded as a destructive test.  For test procedure, see Appen dix B . 
 
DKS 251:2020  ©KEBS  
8  7.3 Filler Neck Test — This test shall be carried out on samples from new model production . It shall also 
be carried out on a random basis on at least one in every 100 radiators of same type produced. For test 
method, see Appendix C.  
 
7.4 Pulsation  Test — This test shall be carried out, on samples of new model production in conjunction  
with tests under clause 7.2 above. Spot checks shall also be carried out at least once per 500 units of 
same type produced. For test procedure, see Appendix D.  
 
NOTE :     This test is regarded as a destructive test.  
 
7.5 Repaired Radiators  — Any radiators repaired  after tests 7.1. and 7.3  shall be retested to pass the 
tests.  
 
8.0 Packaging and Marking  
 
8.1 Marking  
 
Each radiator shall be legibly and  indelibly  marked  on the outer casing  with: 
 
(i) Manufacturer’s name or trade mark;  
 
(ii) Part number;  
 
(iii) Country of origin  
 
 
           8.2 Packaging  
 
 8.2.1  Each radiator shall be packaged in such a manner that it is protected from damage during 
transportation and storage  
               
             8.2.2  Each package shall be legibly and indelibly marked with: - 
               
(i) Manufacturer’s name or trade mark  
(ii) Part number  
(iii) Country of origin  
 
 
Annex  A 
 
Pressure test  
 
A1. TEST ARRANGEMENT  
 
This test shall be conducted in a suitably sized tank full of water sufficient to immerse the radiator. 
Provision shall be made for connecting the radiator to a compressed air line.  
 
 
A2. METHOD OF TEST   
 
The radiator shall be immersed in water at normal temperature with all outlets blocked off and 
subjected to an  internal air pressure of twice the cap opening pressure for at least 2 minutes.  
 
A3. During the test no sign of air leakage shall be noticeable. Every radiator shall undergo andpass this 
test. 
 
 
 
 
 
 
  
                9  
 
 
 
 
 
APPENDIX    B 
 
VIBRATION TEST  
 
B1. TEST ARRANGEMEN T 
 
 This test shall be conducted on a suitable rig, causing vibration in the vertical direction only . 
 
 
B2. METHOD OF TEST  
  
The radiator shall be mounted on the rig using the normal mounting points and filled with water at 
working pressure. The radiator  shall be made to vibrate in the vertical direction to give an acceleration 
3g. The test shall continue until 106 vibrations are completed.  
 
B3. During or after the test, no leakage shall be noticeable. The mountings of the radiators shall also show 
no crack s or failure.                                                                                                                                                                                                                                                                                                                                                         
 
 
 
 
APPENDIX C 
 
LEAKAGE TEST FOR FILLER NECK SEATS  
 
(This test shall be performed for the filler cap closed position. ) 
 
C1. METHODS OF TEST  
 
Immerse the c omplete radiator assembly with pressure cap into water at room temperature and all 
other outlets blocked off.  Apply a gradually increasing air pressure to coolant ducts.  
 
C2. No air leaks from overflow tube shall be permitted up to a pressure of 5 kpa bel ow the nominal 
pressure required to operate the pressure cap relief valve.  
 
NOTE:      The pressure cap used during this test should be previously checked for accuracy.  
 
  
 
 
 
 
APPENDIX D 
 
PULSATION TEST  
 
D1. TEST ARRANGEMENT   
 
This test shall be conducted o n a suitable rig holding the radiator vertically by its normal mounting 
points . Provision shall be made for connecting the radiator to a constant hot water supply (at least 80 
ºC) and also to compressed air.  
 
D2. Hot water shall be continuously circulated through the radiator. Provision shall be made to 
automatically increase/decrease the internal system pressure at a controlled rate. The pressure shall 
be cycled from zero such to 1½ times cap opening pressure and back to zero such that one cycle is DKS 251:2020  ©KEBS  
10  complet ed in 3 seconds to 5 seconds. The test shall run continuously until 30 000 cycles have been 
completed. During the test, the pressure relief cap (if fitted) shall be substituted with a non -opening 
cap. 
 
D3. During the test, no leakage shall be noticeable.