Welcome to On Site Auto Repair!
Auto Repair in Cotati, CA
Reliable auto repair in Cotati, CA for brake repair, check engine diagnostics, oil changes, smog inspection and repair, wheel alignment, tire replacement and rotation, suspension and steering work, AC service, battery replacement, and scheduled maintenance for most makes and models.
Visit our Cotati-based auto repair shop today for top-tier, local service you can trust.
Our Auto Repair Services in Cotati, CA
Brake Repair Cotati, CA
Brake Repair in Cotati, CA? We diagnose squeals, pulsation, pulling, and soft pedals caused by stop‑and‑go on Old Redwood Highway, East Cotati Avenue roundabouts, and wet roads. Services include brake pad and shoe replacement, rotor/drum resurfacing or replacement, caliper and wheel cylinder repair, brake fluid exchange, and ABS diagnostics. Expect digital inspections, same‑day turnaround, and parts matched to Toyota, Honda, Ford, Chevy, and Dodge. We road‑test near the Hwy 101 ramps and La Plaza Park to verify safe stops. Schedule Brake Repair in Cotati, CA today. Choose Brake Repair in Cotati, CA for shorter stopping distances and quieter brakes.
Radiator Repair Cotati, CA
Radiator Repair in Cotati, CA keeps you from overheating on Highway 101, the Cotati Grade, and La Plaza stops. We diagnose coolant leaks, clogged cores, weak thermostats, failing water pumps, and hoses, then fix them so you avoid head‑gasket damage and roadside stalls. We pressure‑test, check fan operation, verify circulation, flush contaminated coolant, replace radiators, caps and hoses, and reset air pockets after service. Findings and parts that fit Toyota, Honda, Ford, Chevy, Subaru, and more. Schedule Radiator Repair in Cotati, CA or maintenance before summer heat or weekend wine‑country traffic. Choose Radiator Repair in Cotati, CA for turnaround.
Check Engine Light Repair Cotati, CA
Need accurate Check Engine Light Repair in Cotati, CA? Local technicians pinpoint why your CEL is on—loose gas cap from Costco runs, failing O2 sensors, evap leaks after Petaluma Hill Road potholes, or P0420 from catalytic converter issues common in Sonoma County. We use OEM-level scanners to read live data, verify readiness monitors for smog checks, and separate urgent faults from minor warnings so you avoid tow bills and test failures. Get same-day diagnostics near Redwood Highway and Highway 101, ideal for SSU commuters and parents on school drop‑off routes. Schedule Check Engine Light Repair in Cotati, CA today.
Auto AC Repair Cotati, CA
Need Auto AC Repair in Cotati, CA? Beat summer heat and morning coastal fog with fast diagnostics, refrigerant recharge for R-134a or R-1234yf, and precise leak detection. Fix weak airflow after Highway 101 stop-and-go, restore cool air during Old Redwood Hwy errands, and ensure defrost for foggy trips through the Cotati Hub. We repair compressors, condensers, evaporators, blend doors, thermostats, and heater cores, and program climate controls. We also replace cabin filters clogged by wildfire smoke and pollen. Schedule Auto AC Repair in Cotati, CA to stay comfortable and safe. Choose local Auto AC Repair in Cotati, CA today.
Oil Change Cotati, CA
Need an Oil Change in Cotati, CA? Tackle stop‑and‑go on Old Redwood Highway, Highway 101 commutes, and short trips to SSU with synthetic oil that resists fuel dilution. We follow manufacturer specs, protect warranties, replace oil and filters, top off fluids, and check brakes and leaks. Vineyard dust and wildfire smoke clog filters; we inspect engine and cabin filters for Cotati. Subaru and Toyota owners benefit from OEM‑grade oils that handle coastal fog and summer heat. Get service near La Plaza Park and the Cotati SMART station. Book Oil Change in Cotati, CA today—choose Oil Change in Cotati, CA.
Suspension Repair Cotati, CA
Need Suspension Repair in Cotati, CA because your car clunks over Old Redwood Highway or drifts on 101 on‑ramps? We replace shocks and struts, align wheels, fix power steering leaks, and swap worn ball joints and tie rods to stop uneven tire wear and restore straight tracking. Winter potholes around La Plaza Park and West Sierra Avenue can bend components; we inspect suspension, then explain priorities and costs before work. Improve braking stability on the Cotati Grade and comfort on Railroad Avenue. Choose local techs who know Sonoma County roads: Suspension Repair in Cotati, CA for safe, predictable handling.
Tire Shop Cotati, CA
Searching for a Tire Shop in Cotati, CA that fixes vibration from Cotati Grade and pothole damage after winter rains? We install Michelin, Bridgestone, Goodyear, and Continental tires, mount with proper torque, replace valve stems, repair punctures, rebalance wheels, and service TPMS so you drive smooth on Old Redwood Highway, Highway 116, and 101. Drop in for emergency flat repair near downtown roundabouts or schedule replacements before Sonoma State commutes. We service Toyota, Honda, Ford, Chevy, Subaru, Lexus, Acura, Hyundai, and more using road-force balancing and equipment. Choose a Tire Shop in Cotati, CA: Tire Shop in Cotati, CA.
Transmission Repair Cotati, CA
Need Transmission Repair in Cotati, CA? We diagnose harsh shifting on Highway 101 commutes, clutch slip on Old Redwood Highway, leaks after vineyard backroad driving, and vibration from worn CV joints or axles. Services include fluid exchanges, filter replacement, clutch and flywheel work, transfer case service for AWD Subarus and Toyotas, and complete rebuilds for domestic and import models. We use advanced scan tools and road-test around Cotati grade to pinpoint faults, explain options and costs. Get free transmission checks, same-day fixes for minor issues, and towing coordination. Choose local expertise: Transmission Repair in Cotati, CA that keeps you moving.
Auto Repair and Maintenance in Cotati, CA
On Site Auto Repair provides mobile auto repair in Cotati, CA, serving homes, workplaces, and roadside locations. Services include diagnostics with OBD-II scanning, battery testing and replacement, starter and alternator replacement, brake pad and rotor service, oil and filter changes, belt and hose replacement, radiator and cooling system service, spark plug and ignition repair, fluid leaks, and check engine light troubleshooting. We handle scheduled maintenance and many no-start issues on most cars and light trucks, offering convenient on-site service across Cotati and nearby areas.
About Cotati, CA
Cotati, CA centers around its hexagonal downtown plaza, a rare street layout rooted in early ranch-era town planning. The city blends small-scale living with accessible commercial corridors, supporting independent shops and service businesses. Notable landmarks include Cotati City Hall, La Plaza Park, Cotati-Rohnert Park Unified School District offices, Helen Putnam Park, and the Cotati Library. Technicians travel to Cotati addresses and handle jobs curbside near landmarks like La Plaza Park, Sonoma State housing edges, and Old Redwood Highway storefronts. They bring diagnostics, batteries, brakes, oil changes, and electrical fixes to driveways and parking lots, coordinating around street parking rules and school zones for minimal disruption, quick turnaround, and transparent estimates on-site.
Cotati's population is 7,592. City center coordinates: 38.3266, -122.7078. Summers are warm and dry with coastal fog in the evenings; winters are cool, wet, and occasionally windy. On Site Auto Repair uses corrosion-resistant parts, checks battery health after damp, chilly nights, and schedules mobile service around rain windows, while following California regulations on waste oil handling, parts sourcing, emissions-related repairs, and hazardous material disposal. - Downtown Cotati: Mobile diagnostics and brake repairs near La Plaza Park with convenient curbside service. We prioritize eco-friendly practices, using recycled materials and sustainable methods, and we actively support Cotati’s community through local partnerships and events. Proudly serving Cotati, CA. For reliable Auto Repair services in Cotati, contact On Site Auto Repair today.
Cities We Serve
Neighborhoods We Serve
Things to Do
Scandia Family Fun Center
Cotati Historical Society
Karah Estate Vineyards
Rebounderz Rohnert Park - Indoor Trampoline and Adventure Park
La Plaza de Cotati
Cotati Veterans memorial building
Alicia Park
Reed Between The Lines
Sonoma Coast State Park
Stones Throw
Spancky's
Mercy Wellness Of Cotati
Libarle Vineyards
Flagship Taproom
Cotati
Grav South Brew Co.
Eight Ball
Jaded Toad BBQ & Grill Cotati
Cal Skate of Rohnert Park
Transportation
Cotati Hub
East Cotati Ave & La Salle Ave
East Cotati Ave & Santero Way
Old Redwood Hwy & Page St
East Cotati Ave & Camino Colegio Ave
Hwy 116 & Redwood Dr
East Cotati Ave & La Salle St
East Cotati Ave & Sunflower Dr
Old Redwood Hwy & St Joseph Way
E Cotati/Lancaster
East Cotati Ave & Lancaster Dr
East Cotati Ave & Cristobal Way
East Cotati Ave & Adrian Dr
Old Redwood Hwy & St Joseph Way
Old Redwood Hwy & George St
Raley's Town Center
East Cotati Ave & Camino Colegio Ave
Camino Colegio & East Cotati Ave
East Cotati Ave & Ryan Lane
East Cotati Ave & Snyder/Maurice
Driving Directions
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Frequently Asked Questions
Our certified mechanics answer the most common car repair questions to help you stay informed and confident. Explore our FAQs for honest, expert advice trusted by Santa Rosa drivers.
Do you provide loaner cars or shuttle service?
While we don't provide loaners, we're located in downtown Santa Rosa's Railroad Square with easy access to shopping, dining, and public transportation while you wait.
Can you work on my vehicle if it's still under warranty?
Absolutely! We perform warranty-compliant maintenance and repairs. We use OEM or equivalent parts to maintain your vehicle's warranty coverage.
How do I know if I really need the recommended service?
We provide detailed explanations and show you exactly what needs attention. We never pressure you into unnecessary repairs - our reputation depends on honest service.
Do you offer payment plans for major repairs?
We accept cash, check, and all major credit cards. For major repairs, we can discuss payment options that work for your budget.
What if my car breaks down outside of business hours?
Call our main number (707) 326-8655 and leave a message. We'll get back to you first thing in the morning to arrange service.
ReviewsWhat Our Clients Say
Brands We ServiceAuto Repair Brand
Toyota Repair
Honda Repair
Ford Repair
Chevrolet Repair
Nissan Repair
Mercedes Repair
Lexus Repair
Acura Repair
Infiniti Repair
Kia Repair
Hyundai Repair
Subaru Repair
Mazda Repair
Volkswagen Repair
Contact Info
Location
363 W 9th St B & C
Santa Rosa, CA 95401
Phone
707-326-8655
Hours
- Monday-Thursday: 7:30 AM - 4:30 PM
- Friday: 7:30 AM - 12:00 PM
- Saturday: Closed
- Sunday: Closed
New Customer Special:
$25 off your first service over $100. New customers only. One per household. Mention this offer when you call. Valid through December 31, 2026.
Oil Change Special:
Full synthetic oil change for $69.99. Includes up to 5 quarts of oil and a new oil filter. Most cars and light trucks. Valid through December 31, 2026.
Free Brake Inspection
Free brake inspection. We check pads, rotors, fluid, and lines and give you a written report. No purchase required.
Latest News
Why Is My Coolant Light On in Sebastopol? What Low Coolant Actually Means for Your Engine
If your coolant warning light just came on near Sebastopol or anywhere in Sonoma County, don’t ignore it — low coolant can lead to serious engine damage fast. This guide explains what that light actually means, what causes coolant loss, and when you need to get it checked before a small problem becomes a very expensive one.
Why Are My Shocks and Struts Worn Out Already? What Healdsburg and Sonoma County Drivers Need to Know
If your ride feels bouncier than usual, or your car nose-dives when you brake, your shocks and struts might be telling you something. Here’s how to recognize the warning signs, why Sonoma County roads accelerate wear, and what to expect when you bring your vehicle in for suspension service.
How Do You Know When Your Car Battery Is Dying in Windsor or Santa Rosa? Signs, Tests, and What to Do
A dying car battery doesn’t always announce itself with a dramatic no-start. Learn the early warning signs Santa Rosa and Windsor drivers should watch for, what a proper battery test involves, and when it’s time to replace — before you’re stranded.
How Often Should You Change Your Transmission Fluid in Rohnert Park? Here’s What You Need to Know
Transmission fluid doesn’t get talked about as much as oil changes, but skipping it is one of the most expensive mistakes a driver can make. If you’re in Rohnert Park or anywhere in Sonoma County, here’s what you actually need to know about transmission fluid intervals, warning signs, and what happens when you wait too long.
Why Is My Car Shaking When I Drive? Steering and Suspension Warning Signs in Santa Rosa
If your car shakes, pulls to one side, or feels like it’s bouncing over every little bump, your steering or suspension is trying to tell you something. Here’s what those symptoms actually mean for Santa Rosa drivers — and when to get it looked at before a small problem becomes an expensive one.
Why Is My Car’s AC Blowing Warm Air in Petaluma? What’s Going On and How to Fix It
If your car’s AC is blowing warm air this summer, you’re not imagining it — and you’re definitely not alone in Petaluma or anywhere across Sonoma County. This article breaks down the most common reasons your AC stops cooling, what the warning signs mean, and when it’s time to bring it in for a proper diagnosis.
Why Is My Check Engine Light On in Santa Rosa? What It Actually Means and What to Do Next
That little amber light on your dashboard can mean anything from a loose gas cap to a failing catalytic converter — and most Santa Rosa drivers have no idea which one they’re dealing with. Here’s what the check engine light actually means, when it’s safe to keep driving, and when you need to pull over and call a shop right away.
Why Are My Brakes Squealing in Santa Rosa? What It Means and When to Get It Fixed
That high-pitched squeal when you hit the brakes is your car trying to tell you something — and in Santa Rosa, where hilly neighborhoods and long Highway 101 commutes put real strain on your braking system, it’s worth listening. This guide breaks down exactly what brake noise means, when it’s urgent, and what you can expect from an honest brake inspection.
Why Is My Car Overheating in Petaluma? What to Do and When to Get It Checked
If your temperature gauge is climbing or you’re seeing steam from under the hood around Petaluma or anywhere in Sonoma County, don’t ignore it. Overheating is one of the fastest ways to turn a minor repair into a major engine problem — here’s what’s actually happening, what to do in the moment, and when to bring it in.
Essential Hyundai maintenance tips for long-lasting performance
With regular maintenance, you can ensure that your Toyota performs at its best in the beautiful surroundings of Santa Rosa, CA. This guide offers imperative tips tailored to the unique driving conditions and climate in the area, helping you keep your vehicle in top...
Read More About Our Auto Mechanic Services
On Site Auto Repair in Santa Rosa is a full service auto mechanic shop. Our auto mechanics are certified and are here to help with all of your repair needs. No auto repair job is too big or too small for On Site Auto Repair. We handle all types of auto repair, including regular maintenance, engine repair, brake work, and troubleshooting. If you are looking for honest and reliable auto mechanics, give us a call today. Ask us about our new customer specials.
Vehicles are usually described as 5 speed or 6 speed, meaning they have that many gear ratios. Those gears let the vehicle travel across the full range of speeds and use the engine's power efficiently. Transmissions are complex and are in constant use, so they take a lot of wear and tear. Many owners also forget to check and change the fluid on a regular schedule. That is why transmission problems are so common. At On Site Auto Repair in Santa Rosa, our transmission technicians can diagnose, repair, or replace your transmission. If you are looking for an honest transmission repair shop, give us a call today.
There are several warning signs that your vehicle can give you before your brakes may reach the point of potential failure or extensive repair. Whether composed of ceramic, semi-metallic, or organic materials, brake pads erode each time you depress the brake pedal. If the pads wear down too much without being replaced, the metal housing for the pads will make contact with the metal rotors (or drums), which may produce not only a safety issue but a situation where the rotors/drums are required to be replaced as a result of the prolonged contact of metal parts without the pad buffer. If you are in need of an affordable brake repair mechanic in Santa Rosa, please do not hesitate to schedule an appointment today!
Vehicle Inspection In Santa Rosa
The key to top notch automotive repair and troubleshooting lies in a thorough understanding of what’s actually going on under the hood. Sure, you know that a radiator keeps your engine cool, but understanding how it keeps it cool is the key to solving technical problems efficiently. If you know which parts perform what function, your powers of diagnosis will be much more powerful.
Radiator Inspection Service In Santa Rosa
Ensuring that your vehicle’s engine cooling system is in proper operating condition is extremely essential to engine life and performance. Operating at excessive temperatures can lead to premature engine wear. Your vehicle’s engine cooling system should be checked periodically, and a radiator coolant flush is also recommended to prohibit radiator corrosion. On Site Auto Repair will thoroughly drain and power flush the old coolant and particulates, and refill the cooling system with your vehicle manufacturer’s recommended coolant.
Our Santa Rosa Service Area – Directions to On Site Auto
Proudly serving drivers throughout Santa Rosa neighborhoods, from Railroad Square to Bennett Valley, and extending our trusted auto repair services to Petaluma, Sebastopol, Windsor, and all of Sonoma County.
Auto Repair Services We Offer in Santa Rosa, CA
Our shop at 363 W 9th St B & C handles a wide range of repairs and maintenance for drivers across Santa Rosa and Sonoma County.
Engine Diagnostics and Check Engine Light
A check engine light means your car is reporting a fault. We connect an OBD-II scanner, read the fault codes, and explain what they mean in plain language. We diagnose the problem first, then tell you what the repair will cost.
Oil Change Service
We do full-synthetic and conventional oil changes. We use the viscosity grade your manufacturer specifies, such as 5W-30, 5W-20, or 0W-20, and we replace the oil filter every time.
Brake Repair and Replacement
Worn brake pads squeak. Worn rotors grind. A soft brake pedal is a warning. We inspect and replace brake pads, rotors, and calipers using OEM-quality and aftermarket parts, depending on your budget.
Battery, Alternator, and Starter Repair
We test your battery with a load tester, not just a voltage check. We also test the alternator and starter, because a failing alternator will kill a new battery quickly.
AC and Heating Repair
If your AC is not blowing cold, we recharge the refrigerant and check for leaks. If your heat is not working, we diagnose the cause and repair it.
Scheduled Maintenance and Tune-Ups
We handle spark plug replacement, belt inspection and replacement, air and cabin filter replacement, fuel system service, coolant flushes, and transmission fluid service. If you are not sure what your car is due for, we look it up by make, model, and mileage.
Tire Rotation and Inspection
Uneven tire wear affects handling, fuel economy, and tire life. We rotate your tires, measure tread depth, inspect the sidewalls, and check the pressure.
Pre-Purchase Inspection
Thinking about buying a used car? We check the brakes, belts, fluids, undercarriage, and suspension, and we run a diagnostic scan for hidden fault codes. Call for current pricing.
Why Santa Rosa Drivers Choose On Site Auto Repair
Free estimates. You know the cost before we start any work.
Same-day appointments available. Call and we will tell you what we can fit in today.
ASE Certified mechanics. Credentialed professionals with real diagnostic tools.
Convenient location. We are in Railroad Square, minutes from downtown Santa Rosa, with shops and restaurants in walking distance while you wait.
Ready to Book?
Call (707) 326-8655 or send us a message with your vehicle and what is going on with it. We will give you a free estimate before we schedule anything.
On Site Auto Repair — 363 W 9th St B & C, Santa Rosa, CA 95401. Serving Santa Rosa, Petaluma, Rohnert Park, Sebastopol, Windsor, Healdsburg, and Sonoma County.
Things To Do In Santa Rosa, CA
From exploring the Charles M. Schulz Museum and Luther Burbank Home & Gardens to enjoying outdoor adventures at Spring Lake Regional Park and Annadel State Park, Santa Rosa offers endless opportunities for family fun, Wine Country experiences, and recreational activities that keep our community vibrant year-round.
Santa Rosa Transportation to On-Site Auto Repair
Conveniently located in the historic Railroad Square district with easy access from Highway 101, our auto repair shop is just minutes from downtown Santa Rosa, Santa Rosa Plaza, and all major neighborhoods, with nearby public transit options and walkable access to local shops and restaurants while your vehicle is being serviced.
Contact On-Site Auto Repair Today
Ready to experience honest, reliable auto repair in Santa Rosa?
Whether you’re dealing with a check engine light, need routine maintenance, or facing an unexpected breakdown, our ASE-certified mechanics are here to help. We serve drivers throughout Santa Rosa and Sonoma County with the same commitment to quality and honesty that has made us the area’s most trusted auto repair shop.