Mazda North American Operations
Irvine, CA 92618-2922

Service Alert
Subject:

VALVE TAPPING OR KNOCKING NOISE HEARD FROM CYLINDER
HEAD

Service Alert No.: SA-025/20

Last Issued: 02/11/2020

BULLETIN NOTES
This service alert supersedes the previously issued service alert listed below. The changes are noted in
Red text.

Previous Service Alert:

Date(s) Issued:

SA-012/19

11/22/2019, 08/06/19 and04/01/19

APPLICABLE MODEL(S)/VINS
2018-2019 CX-5 vehicles (2.5L with cylinder deactivation)
2018-2019 Mazda6 vehicles (2.5L with cylinder deactivation)

DESCRIPTION
A valve tapping or knocking noise may be heard from the top end after the engine cools down (the vehicle
is parked overnight) or after it has been idling for an extended time. The tapping noise will decreases as the
vehicle is being driven or if the rpm is held above 2500 -3000 RPM. This may be caused by the valve
Hydraulic Lifters (HLA) bleeding down as the engine cools or when the engine has been idling for an
extended period of time, creating excessive valve lash clearance.
Click here for an example of the noise.

REPAIR PROCEDURE
1. Verify customer concern and that the tapping sound is coming from the cylinder head.
NOTE: If the symptom cannot be reproduced, allowing the vehicle to sit overnight and inspect in it the
morning.
Can the Tapping or Knocking sound be reproduced?



Yes: Go to step 2.

Page 1 of 3
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2020 Mazda North American Operations, U.S.A.
02/11/2020 3:48 PM tlawrenc

Service Alert No.: SA-025/20



Last Issued: 02/11/2020

No: Interview the customer when they experienced the condition and try to reproduce the
conditions. If unable to reproduce the tapping sound, this SA does not apply

2. Before performing repair work. Record a video of the engine being started and the tapping noise.
Attach video to the hotline case.
3. Remove the valve cover and rotate the engine until the rocker arm is on the base circle of the cam, then
perform a HLA inspection (HYDRAULIC LASH ADJUSTER (HLA) INSPECTION [SKYACTIV-G 2.5 (WITH
CYLINDER DEACTIVATION)]





If any HLA fails the inspection, replace the appropriate HLA (HYDRAULIC LASH ADJUSTER (HLA)
REMOVAL INSTALLATION [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)). Package
each set (2) of HLA in a plastic bag and identify on the bag the location it was removed from.
Example: #2 exhaust.
If the HLAs pass the inspection, re-assemble and proceed to step 4.

4. Using a listening device or stethoscope, start the engine and listen to each cylinder's intake and exhaust
side to determine the location of tapping sound. It may only last for a short time.





If the tapping can be isolated, replace the appropriate HLA's ( HYDRAULIC LASH ADJUSTER
(HLA) REMOVAL INSTALLATION [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)).
Package each set (2) of HLA in a plastic bag and identify on the bag the location it was removed
from. Example: #2 exhaust.
If the tapping can not be isolated, replace all the HLA's (HYDRAULIC LASH ADJUSTER (HLA)
REMOVALINSTALLATION [SKYACTIV-G 2.5 (WITH CYLINDER DEACTIVATION)). Package each
set (2) of HLA's in a plastic bag and identify on the bag the location it was removed from. Example:
#2 exhaust.

Page 2 of 3
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2020 Mazda North American Operations, U.S.A.
02/11/2020 3:48 PM tlawrenc

Service Alert No.: SA-025/20



Last Issued: 02/11/2020

Parts will be collected through normal warranty part collection

WARRANTY INFORMATION
Normal Warranty applies

Page 3 of 3
CONSUMER NOTICE: The information and instructions in this bulletin are intended for use by skilled technicians. Mazda technicians utilize the proper tools/
equipment and take training to correctly and safely maintain Mazda vehicles. These instructions should not be performed by “do-it-yourselfers.” Customers
should not assume this bulletin applies to their vehicle or that their vehicle will develop the described concern. To determine if the information applies,
customers should contact their nearest authorized Mazda dealership. Mazda North American Operations reserves the right to alter the specifications and
contents of this bulletin without obligation or advance notice. All rights reserved. No part of this bulletin may be reproduced in any form or by any means,
electronic or mechanical---including photocopying and recording and the use of any kind of information storage and retrieval system ---without permission in
writing.

© 2020 Mazda North American Operations, U.S.A.
02/11/2020 3:48 PM tlawrenc