Welcome to On Site Auto Repair!
Our Services
Complete Auto Repair Services — Done Right the First Time
From brake and transmission repair to diagnostics and routine maintenance, our certified mechanics handle all makes and models with precision, honesty, and fast turnaround.
Serving Santa Rosa Since 2011
★★★★★ 4.8/5 (100+ Reviews)
Complete Auto Repair Services in Santa Rosa
From routine maintenance to complex repairs, we handle it all with precision and care. Trust our certified mechanics to keep your vehicle running smoothly and safely.
Brake Services
- Brake pads, rotors, fluid replacement
- “Starting at $89”
Read More
Transmission Repair
- Automatic & manual transmission service
- “Free diagnostic”
Read More
Engine Repair & Diagnostics
- Automatic & manual transmission service
- “Free diagnostic”
Read More
Read More
Heating & AC Service
- Climate control repair, refrigerant service
- “Stay comfortable year-round”
Read More
Steering & Suspension
- Shocks, struts, alignment service
- “Smooth, safe driving”
Read More
Cooling System Service
- Radiator repair, coolant flush
- “Prevent overheating”
Auto 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-Friday: 8:00 AM - 5:30 PM
- Saturday: 8:00 AM - 4:00 PM
- Sunday: Closed
New Customer Special:
$25 Off First Service Over $100
Oil Change Special:
Full Synthetic Oil Change – $69.9
Free Brake Inspection
Complete brake system check at no charge
Latest News
Why Is My Subaru Using So Much Oil Between Changes in Healdsburg? What Subaru Owners Need to Know
If your Subaru is burning through oil faster than it should, you’re not alone — and it’s not something to ignore. Here’s what’s actually causing excessive oil consumption in Subarus, which models are most affected, and what Healdsburg and Sonoma County drivers should do about it.
Why Is My Car’s Heater Not Working in Sebastopol? What to Check Before Winter Gets Worse
If your car’s heater is blowing cold air or barely warming up during Sonoma County’s wet winters, it’s more than just a comfort issue — it can affect your defroster, visibility, and engine health. Here’s what’s likely going on and when to bring it in for a proper diagnosis.
How Do You Know If Your Car Needs a Wheel Alignment in Windsor or Santa Rosa?
If your car is pulling to one side, your steering wheel feels off-center, or your tires are wearing unevenly, you probably need a wheel alignment. Here’s how to recognize the signs, why Sonoma County roads are especially hard on alignment, and when to get it checked.
Why Is My Car Hesitating When I Accelerate in Santa Rosa? What’s Causing That Sluggish Response
If your car hesitates, stumbles, or feels sluggish when you press the gas pedal in Santa Rosa or anywhere in Sonoma County, something is off — and it’s usually more than just a minor annoyance. This article explains the most common causes of acceleration hesitation, what warning signs to watch for, and when it’s time to bring your vehicle in before a small problem turns into a costly repair.
Why Is My Car Making a Grinding Noise When I Turn in Petaluma? What’s Going On with Your CV Axles and Wheel Bearings
A grinding or clicking noise when you turn your steering wheel is one of those symptoms you shouldn’t ignore — it usually means your CV axles or wheel bearings are telling you something important. If you’re driving around Petaluma or anywhere in Sonoma County and noticing this sound, here’s what it actually means and when to get it checked.
Why Does My Car Smell Burning When I Drive in Sonoma County? What Different Smells Actually Mean
A burning smell coming from your car is never something to ignore — and different smells point to very different problems. Here’s how to identify what you’re smelling and what to do about it before a minor issue turns into a major repair.
Why Is My Car Leaking Fluid in Petaluma? How to Identify What’s Dripping Under Your Vehicle
A puddle under your car isn’t always serious — but it’s never something to ignore. This guide helps Petaluma and Sonoma County drivers identify common fluid leaks by color, location, and smell, and explains when it’s safe to drive and when you need to pull over immediately.
Why Is My Oil Looking Dark and Gritty in Rohnert Park? What Your Engine Oil Is Actually Telling You
Dark, gritty, or milky engine oil is your car’s way of sending you a warning signal — and ignoring it can turn a simple oil change into a costly engine repair. If you’re a driver in Rohnert Park or anywhere in Sonoma County, here’s what your oil is actually telling you and when to act.
Why Is My Engine Running Rough After a Cold Start in Sebastopol? What Misfires and Rough Idle Actually Mean
If your engine stumbles, shakes, or sputters during the first few minutes after a cold start, it’s not something to ignore. For drivers in Sebastopol, Santa Rosa, and across Sonoma County, here’s what’s actually causing it — and when you need to bring it in.
Why Is My Tire Pressure Light On in Sonoma County? What TPMS Warnings Actually Mean
That little horseshoe-shaped light on your dashboard isn’t something to ignore — but it’s also not always a reason to panic. Here’s what your TPMS warning light actually means for Sonoma County drivers, when it’s a quick fix, and when something more serious might be going on.
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 here to help you with all of your automotive repair needs. No auto repair job is too big or too small for On Site Auto Repair.We specialize in all types of auto repair, including: regular maintenance, break/fix, engine repair, troubleshooting and much more! 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 or 6 “speed” meaning then have that many gear ratios to allow the vehicle to travel at the full range of speeds required and to make use of the engine’s output power as efficiently as possible. Due to their complexity, constant use and function within a vehicle’s operation, transmissions experience a lot of wear and tear. Add to this the fact that many owner’s forget to check and change the fluid on a regular basis and it’s easy to understand why so many people have transmission problems. At On Site Auto Repair in Santa Rosa, our transmission repair technicians can accurately diagnose, repair or replace your transmission. If your are looking for a reliable and honest transmission repair services company, 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 Mechanic Services We Offer in Sonoma, CA
We handle a wide range of repairs and maintenance, all performed at your location. Here's what we do most often for drivers in Sonoma and nearby areas like Glen Ellen, El Verano, Kenwood, Petaluma, and Santa Rosa.
Engine Diagnostics and Check Engine Light
That check engine light makes most people nervous — and honestly, it should. It's your car telling you something's off. We plug in an OBD-II scanner, pull the fault codes, and actually explain what they mean in plain English. No guesswork, no upselling you on repairs you don't need.
We diagnose the problem first, then give you a straight answer about what it will take to fix it.
Oil Change Service
We do full-synthetic and conventional oil changes at your home or workplace. We use the correct viscosity grade for your vehicle — 5W-30, 5W-20, 0W-20, or whatever your manufacturer specifies — and we replace the oil filter every time.
Honest truth: most people wait too long between oil changes. It's the cheapest maintenance you can do to extend the life of your engine. We make it easier by bringing it to you.
Brake Repair and Replacement
Worn brake pads squeak. Worn rotors grind. Soft pedals are a warning you shouldn't ignore. We inspect and replace brake pads, rotors, and calipers using both OEM-quality and aftermarket parts, depending on your preference and budget.
If you're hearing anything unusual from your brakes, don't wait. Brake jobs that get delayed usually end up costing more.
Battery Replacement and Testing
Dead batteries don't give much warning. We test your battery with a proper load tester — not just a voltage check — and if it's on its way out, we replace it with an AGM or standard lead-acid battery sized for your vehicle. We also check the alternator and charging system while we're at it, since a bad alternator kills new batteries fast.
Alternator and Starter Repair
If your car won't start or your battery keeps dying, the problem is often the alternator or starter. We test both, figure out which one is the culprit, and fix it on-site. This is exactly the kind of repair people think requires a shop — it usually doesn't.
AC and Heating Repair
Sonoma summers get warm. If your AC isn't blowing cold, we can recharge the refrigerant and check for leaks. If your heat isn't working in the colder months, we'll diagnose the issue and get it sorted. Comfort on the road matters, and we don't treat climate control as a low-priority service.
Scheduled Maintenance and Tune-Ups
Staying on top of scheduled maintenance is the single best way to avoid expensive repairs down the road. We handle:
- Spark plug replacement (iridium and platinum)
- Timing belt and serpentine belt inspection and replacement
- Air and cabin filter replacement
- Fuel system service and fuel injector cleaning
- Coolant system flush (HOAT and OAT compatible formulas)
- Transmission fluid flush and filter service
If you're not sure what your car is due for, we'll check your maintenance records or look it up by your vehicle's make, model, and mileage. We won't pad the list.
Tire Rotation and Inspection
Uneven tire wear is more than an aesthetics problem. It affects handling, fuel economy, and how long your tires last. We rotate your tires, check tread depth, inspect sidewalls, and check pressure. Simple service, done where you are.
Pre-Purchase Inspection
Thinking about buying a used car? Get it inspected before you commit. We'll look at what matters: brakes, belts, fluid conditions, undercarriage rust, suspension, and run a diagnostic scan for hidden fault codes. A $100-150 inspection can save you thousands on a bad purchase. We serve buyers all across the Sonoma Valley and into Napa County.
Roadside Assistance and Emergency Repairs
Stuck in Kenwood? Broken down near El Verano or out on Highway 12? If it's something we can fix on the spot, we will. Give us a call and we'll tell you honestly whether we can help or whether you need a tow.
Why Sonoma Drivers Choose On-Site Auto Repair
Most auto shops in and around Sonoma, CA do good work. The problem isn't the quality — it's the hassle. Drop the car off, wait for a call, figure out a ride home, go back and pick it up. That cycle eats your whole day.
We skip all of that.
Here's what you actually get when you book with us:
No tow truck needed. If your car starts (or even if it doesn't and you're local), we come to you. No dragging your car across town.
Flat-rate, upfront pricing. You know what it costs before we touch anything. No surprises when you get the bill.
Same-day appointments available. We know car problems don't schedule themselves. We do our best to get to you fast.
ASE Certified mechanic. Not a weekend hobbyist. A credentialed professional with real diagnostic tools.
California BAR Licensed. We're registered with the Bureau of Automotive Repair, which means we follow the rules and you have legal protections if something goes wrong. Most customers don't know to ask about this, but it matters.
Parts and labor warranty. Every repair is backed by a 12-month / 12,000-mile warranty. We stand behind our work.
We've been serving Sonoma, CA and the surrounding Sonoma County communities for years. Our Google reviews tell the story better than we can.
Ready to Book? Here's How It Works
Call or message us with your vehicle, location, and what's going on with your car.
Get a free estimate before we schedule anything.
Pick a time that works for you — at your home, office, or wherever the car is.
We show up, fix it, and you pay after the job is done.
That's it. No waiting rooms. No borrowed rides. No surprises on the bill.
On-Site Auto Repair — Sonoma, CA Serving Sonoma Valley, Glen Ellen, El Verano, Kenwood, Petaluma, Santa Rosa, and surrounding 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.
























