What maintenance should you do at 30,000 miles?

At 30,000 miles, most vehicles need a comprehensive inspection plus a few routine replacements: rotate tires (and check alignment), replace the engine air filter and cabin air filter, inspect brakes and suspension, test the battery, and check all fluids—changing the engine oil if due and replacing brake fluid if it’s 2–3 years old. Transmission/CVT and AWD/4×4 driveline fluids are often “inspect or replace depending on usage,” while spark plugs typically wait until 60,000+ miles unless your owner’s manual says otherwise.

What typically gets serviced at 30,000 miles

This is a common milestone where wear items and safety-critical systems get a closer look. The following items are widely recommended by automakers and independent service schedules for a 30K service interval.

• Tires: Rotate; check tread depth, age, and uneven wear; consider an alignment check if there’s pull or uneven wear.
• Brakes: Inspect pad thickness, rotors, calipers, and slide pins; measure brake fluid condition (moisture/boiling point).
• Filters: Replace engine air filter and cabin (HVAC) filter; inspect fuel filter if your vehicle uses a serviceable one (many modern cars have “lifetime” in-tank filters).
• Fluids: Change engine oil and filter if due; test/replace brake fluid if 2–3 years old; inspect coolant, transmission/CVT fluid, power steering (if hydraulic), and washer fluid.
• Battery and charging system: Load test the battery and check alternator output; clean terminals if needed.
• Belts, hoses, and cooling: Inspect the serpentine belt, tensioner, coolant hoses, and look for leaks or crusted residues.
• Suspension and steering: Inspect struts/shocks for leaks, bushings, ball joints, tie-rod ends, and wheel bearings.
• PCV and induction: Inspect PCV valve/system if serviceable; clean throttle body/MAF only if idle or drivability issues exist.
• Wipers and lights: Replace wiper blades if streaking; verify all exterior/interior lights work.
• Software and recalls: Check for ECU/TCU updates and open recalls or service campaigns.

Taken together, these checks help catch early wear patterns, maintain braking and handling performance, and prevent avoidable repairs—while keeping warranties intact with documented service.

Fluids at 30K: what to change versus inspect

Fluids age differently based on time, heat, and driving conditions. Here’s how to approach each one at 30,000 miles.

Engine oil

Change if you’re at the oil-life threshold or time limit (often 6–12 months). Many modern engines use oil-life monitors; follow the car’s indicator or the shorter of time/mileage in your manual.

Brake fluid

DOT 3/4 brake fluid is hygroscopic and typically needs replacement every 2–3 years regardless of mileage. If a moisture/boiling-point test shows excess water content (around 3%+), flush now to preserve braking performance and prevent corrosion.

Coolant

Most modern long-life coolants don’t need replacement at 30K; first change is often 5–10 years or 100K–120K miles (then every 50K–60K/5 years). At 30K, inspect level, color, and freeze point; top up with the correct specification only.

Transmission/CVT fluid

Service intervals vary widely. Many automakers say “inspect under normal driving” and replace at 60K+; CVTs and vehicles used in severe service may call for 30K–60K changes. If shifts are harsh or fluid is dark/burnt, service sooner. Always use the exact spec fluid; avoid high-pressure “flushes” without filter service when not recommended by the manufacturer.

Differentials/transfer case (AWD/4×4)

Intervals range from 30K–60K in severe service (towing, off-road) to longer under normal use. If you have frequent short trips in extreme temps, dusty use, or towing, change these fluids now.

Power steering and other fluids

Many newer cars use electric power steering (no fluid). If yours is hydraulic, inspect level and condition; service if dark or contaminated. Don’t forget windshield washer fluid and, for some hybrids/EVs, dedicated coolant loops for inverters/batteries—inspect per the manual.

Tires, alignment, and braking at 30K

Tires and brakes directly impact safety and should be scrutinized at this mileage.

• Rotate tires to even out wear; many manufacturers recommend every 5K–7.5K miles.
• Check tread depth: replace near 4/32 inch for wet traction; 2/32 inch is the legal minimum in many regions.
• Inspect for cupping, edge wear, or center wear; these often indicate alignment or inflation issues.
• Request an alignment check if you notice pull, off-center steering wheel, or uneven wear patterns.
• Measure brake pads/rotors and lubricate slide pins; replace pads if thin or if rotors are below spec.

Correcting alignment and brake issues now prevents premature tire loss and sustains stopping performance, saving money and improving safety.

Do you need new spark plugs at 30K?

It depends on your engine and plug type. Most modern engines use iridium plugs with 60K–120K intervals. Some turbocharged or high-performance engines specify 60K; older or copper-plug engines can be 30K.

• Check your owner’s manual: if it says 30K, replace now; otherwise, wait until the specified interval.
• If you have misfires, rough idle, or poor fuel economy, inspect plugs sooner.

Replacing plugs early rarely adds value on iridium-equipped engines; following the manual is the best approach.

Special cases and “severe service” adjustments

Your environment and driving style can shorten maintenance intervals. If you do any of the following regularly, consider more frequent service and certain 30K changes.

• Frequent short trips, stop-and-go, or extended idling
• Towing/hauling or mountainous driving
• Extreme heat/cold climates
• Dusty/dirty roads or off-road use
• High-performance driving

Under severe service, items like transmission/CVT, differential/transfer case fluids, air filters, and brake fluid often merit earlier replacement. Always default to the severe-schedule column in your manual if these conditions apply.

Hybrids and EVs at 30K

Electrified vehicles have fewer moving parts but still need attention at 30K.

• Rotate tires; EVs are heavier and can wear tires faster.
• Replace cabin filter; check brake fluid condition.
• Inspect brakes (calipers/slide pins can stick with heavy regen use), suspension, and tires for uneven wear.
• Inspect coolant loops for power electronics/battery where applicable (often no replacement yet).
• Check high-voltage system recalls/software updates per manufacturer guidance.

Following the maker’s EV/hybrid schedule ensures thermal systems and braking remain reliable while maximizing range and safety.

Ballpark costs and time

Actual costs vary by vehicle, region, and shop type, but these ranges can help you budget.

• Basic 30K inspection + tire rotation: $80–$180
• Cabin and engine air filters: $40–$120 parts/labor (DIY often $20–$60 in parts)
• Brake fluid flush: $90–$180
• Wheel alignment (if needed): $100–$160
• Transmission/CVT/differential/transfer case service: $150–$450 each, depending on fluid type and access
• Battery test: often complimentary; replacement commonly $130–$300 for ICE vehicles

Combining services in one visit often saves on labor overlap; ask the shop to bundle items efficiently and show you old parts/measurements.

DIY vs. shop: what you can reasonably do

Plenty of 30K items are DIY-friendly with basic tools and care; others are best left to pros due to safety or special fluid requirements.

• DIY-friendly: engine air and cabin filters, wiper blades, washer fluid, battery terminal cleaning, tire pressure checks, visual inspections.
• Pro-recommended: brake fluid flush, transmission/CVT and driveline fluids, alignments, brake servicing, and any job requiring torque specs or special tools.

If you DIY, use OEM-spec fluids/parts and keep dated receipts and notes. Good records can support warranty claims and resale value.

Pre-service checklist

Arriving prepared makes your 30K visit smoother and helps avoid unnecessary upsells.

1. Bring your owner’s manual and note the maintenance table for 30K miles (normal vs. severe).
2. List any symptoms: noises, vibrations, pulling, brake feel, fluid spots on driveway.
3. Request measurements in writing: brake pad thickness, rotor readings, tire tread depths, battery test results, fluid tests.
4. Approve only manufacturer-specified services; ask for old parts back when replaced.
5. Ensure service is logged (paper/in-app) for warranty records.

These steps keep the visit focused on needed work and provide a clear paper trail for future maintenance and warranty support.

Common upsells to treat with caution

Some services are legitimate only in specific circumstances; avoid routine add-ons that don’t match your manual or symptoms.

• Engine “flushes” and generic induction cleanings without a drivability complaint
• Transmission “power flush” on units that require drain-and-fill with filter service
• Premature coolant exchanges if your vehicle uses long-life factory fill
• Fuel system cleaners if your engine runs well and uses Top Tier fuel (except where manufacturer specifies)

When in doubt, ask the shop to cite the exact maintenance line from your owner’s manual and provide test results that justify early service.

Bottom line

At 30,000 miles, prioritize safety and longevity: rotate tires and check alignment; replace engine and cabin filters; inspect brakes and suspension; test the battery; and verify all fluids—changing engine oil if due and brake fluid if 2–3 years old. For transmissions, CVTs, and AWD/4×4 driveline fluids, follow your manual’s normal vs. severe schedule. Spark plugs usually wait until 60K–120K unless specified sooner. Keep records, use the correct fluids and parts, and you’ll set the car up for a trouble-free next 30K.