NHTSA Service Bulletin 10171786: 2018, 2019 Mazda Cx-5
Official manufacturer communication context for 2018, 2019 Mazda Cx-5, with affected products, buyer checks and links into Carchieve recall, problem and VIN research.
Reviewed June 2026 from NHTSA manufacturer communication and service bulletin records. Carchieve is independent and not affiliated with any vehicle manufacturer or government agency.
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.
What this bulletin may mean before buying
Treat this as service research, not a verdict on one car. Before you buy, compare this communication with official recall campaigns, model-level owner complaint patterns, and the exact vehicle’s VIN-decoded specifications. A bulletin can help you ask a seller or dealer sharper questions about software updates, known repairs, warranty extensions and service history.
Affected products listed in this communication
Buyer checklist
- Run the 17-character VIN and confirm the year, make, model, engine and equipment match the listing.
- Check recall campaign pages for safety actions that may require dealer repair.
- Compare this bulletin with common problem pages for the same model and component area.
- Ask the seller or dealer whether the bulletin procedure, update or inspection has already been completed.
- Use the used-car buying checklist and get an independent inspection.
Frequently asked questions
What is NHTSA service bulletin 10171786?
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.
Is a service bulletin the same as a recall?
No. A recall is a safety campaign with a required remedy for affected VINs. A service bulletin or manufacturer communication usually describes diagnostic, repair, software, warranty or service information.
How should a used-car buyer use this bulletin?
Use it as a research signal. Compare it with recalls, owner complaints, service records, a VIN report and an independent inspection before buying.
Check the exact VIN before you buy
Model-level pages show public safety patterns. A full VIN report helps confirm the exact vehicle, decoded specs, recall applicability and buyer checks.
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