Hybrid car maintenance: what differs from a petrol car

What is going on

A hybrid has two power sources, and the maintenance follows both. The petrol engine is a full engine, with the oil, coolant, filters and spark plugs any engine has. In a hybrid it is switched off and restarted constantly, which is designed for and does not remove any of those needs.

The electric side adds parts: a traction battery, an inverter that runs warm and usually has its own cooling, and a DC/DC converter that keeps the 12-volt battery charged in place of a conventional alternator.

Regenerative braking takes much of the everyday slowing down off the brake pads, so they often last considerably longer. But pads and discs used gently can still corrode, and calipers can seize from lack of use.

What changes on a hybrid

• Engine oil: no change in principle, but some hybrids specify a low-viscosity oil, so use the exact specification listed
• Inverter and battery coolant: an additional circuit on many hybrids, with its own reservoir and interval, and not the engine's coolant
• Brake pads and discs: often last longer, but still need inspecting for corrosion and seized calipers
• Brake fluid: unchanged, and still time-based
• Spark plugs: as specified. Frequent engine stop-start does not remove the requirement
• Battery cooling vent or filter: additional on air-cooled packs, and it has to be kept clear
• The 12-volt battery: a normal wear item, and the one most likely to strand you
• The traction battery: no routine owner maintenance

What owners can do

1. Keep the engine on its oil and service schedule, with the exact oil specification in the manual.
2. Check tire pressures and tread depth, the engine oil, washer fluid and, on a cold engine, the coolant levels the manual says you may check.
3. Keep the traction battery's cooling vent clear of bags, child seats and dust, and clean it as the manual specifies where it is an owner job.
4. Have the 12-volt battery tested before winter. Replacing it follows the manual's procedure, which on some hybrids differs from a conventional car.
5. Have the brakes inspected on schedule, even though the pads last longer.
6. If a job turns out to need a panel removed that exposes orange cabling, stop there. It has become a technician's job.

Owner job, or technician job?

• Tire pressures, engine oil, washer fluid, wiper blades and bulbs: owner jobs, as on any car.
• Cabin and engine air filters: owner jobs where they can be reached without tools you don't have.
• The traction battery's cooling vent: an owner job where the manufacturer describes it as one.
• Testing or replacing the 12-volt battery: an owner job, following the manual's procedure exactly.
• The traction battery, the inverter or the electric motor/generator: a qualified hybrid technician only.
• Orange cables, including any that look chafed or damaged: do not touch. Have the car recovered to a qualified workshop.

What people get wrong

That a hybrid needs no engine maintenance. The petrol engine is a full engine and needs its oil and its service intervals. Hybrid is not another word for no maintenance.

When to have it checked

The hybrid system warning light, which is separate from the engine light, needs a technician qualified on hybrid high-voltage systems. Get it checked soon if the engine starts far more often on a route you know, or the car runs on electricity less than it used to. Mention it at the next service if fuel economy has dropped, the battery cooling fan has become louder or runs more often, or brake feel has changed. Describe what you noticed, not what you think is wrong.

Read next

• The EV will not wake up: usually the small battery, not the big one
• P0A00 to P0A0F: motor, inverter and their cooling
• Red high-voltage warning on an EV: stop and call
• Electric car maintenance: what it still needs, and what it skips

This page is general information and does not replace a professional assessment. Symbols, codes and behaviour vary between makes. Always check the handbook for your own car.