Welcome to On Site Auto Repair!
Auto Mechanic in Sonoma, CA — On-Site Auto Repair That Comes to You
Your car has a problem. The last thing you want to do is arrange a tow, sit in a waiting room, or beg for a ride across town. That’s the whole reason On-Site Auto Repair exists.
We’re a locally owned, mobile auto mechanic service based right here in Sonoma, CA. We come to your home, your workplace, or wherever your car is sitting. You don’t rearrange your day. We bring the shop to you.
Whether you’re near Sonoma Plaza, out along Highway 12, or anywhere across Sonoma Valley, our fully equipped service van is ready to handle most repairs on the spot.
What Sets Us Apart from Other Auto Shops in Sonoma
We know you have choices. Sonoma Motors, El Verano Auto Repair, and other local shops do good work. Here’s why some customers prefer coming to us instead.
Convenience is real, not just a talking point. You don’t have to leave your house. That’s a genuine difference, especially for families with one car, remote workers, or anyone who can’t easily arrange a ride across town.
You watch the work get done. Some people like that. There’s nothing hidden in a driveway repair. You can ask questions. You can see what’s being replaced. That kind of transparency builds trust faster than any certificate on a wall.
You’re not getting upsold on a waiting room estimate. We give you a diagnosis. We give you a price. You decide. No pressure, no vague “we noticed a few other things while we were in there.”
We’re local. Not a national franchise. Not a gig-economy app matching you with a stranger. An actual Sonoma-area mechanic who depends on word-of-mouth and repeat customers to stay in business. That means we have every reason to treat you right.
Service Areas in and Around Sonoma, CA
We’re based in Sonoma (zip code 95476) and regularly serve customers throughout:
- Sonoma, CA (our home base, near Sonoma Plaza and surrounding neighborhoods)
- Glen Ellen, CA
- El Verano, CA
- Kenwood, CA
- Petaluma, CA
- Santa Rosa, CA (Sonoma County seat)
- Napa, CA (select services)
Not sure if you’re in our service area? Just call or send us a message. We’ll tell you directly.
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.
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 CA drivers.
Can you really fix my car at my house?
Most of the time, yes. We come equipped with a full set of professional hand tools, a hydraulic jack and stands, an OBD-II scanner, a multimeter for electrical work, and common parts we know we'll need. We can handle the majority of repairs on-site.
The exceptions are things that require a lift or heavy equipment: certain transmission rebuilds, structural frame work, or anything that demands a hoist. When that's the case, we'll tell you upfront and point you somewhere that can help.
How do I know I can trust a mobile mechanic?
That's a fair question. A few things to check on any mechanic — mobile or otherwise:
Are they California BAR licensed? This is a legal requirement for auto repair businesses in California. Ask for their license number. We're happy to share ours.
Are they ASE Certified? ASE (National Institute for Automotive Service Excellence) certification means a mechanic passed a standardized knowledge test in their specialty. It's the industry benchmark.
Do they give you a written estimate before starting work? California law actually requires this. If a shop or mechanic skips this step, that's a red flag.
We check all three boxes. We're also fully insured and bonded, which protects you if something unexpected happens during the repair.
Is it more expensive than going to a shop?
Not necessarily. Because we don't have the overhead of a physical location — rent, utilities, a full front desk staff — our labor rates are often competitive with or lower than traditional shops. And you save on towing costs, which can run $80-200 depending on how far you are from the nearest shop.
We charge flat-rate, upfront pricing. You know the full cost before we start.
How soon can you get to me?
We offer same-day appointments when our schedule allows. For non-emergency services, we typically book within one to two business days. Call us directly for the fastest answer — availability varies by time of year and how many service calls we have going.
During busy periods (particularly summer and around the holidays when wine country visitors stress local roads), book ahead when possible.
Do you work on all types of vehicles?
We work on most domestic, Asian, and European vehicles — cars, trucks, and SUVs. We handle popular makes like Toyota, Honda, Ford, Chevrolet, Subaru, Nissan, Volkswagen, and more.
Some specialty situations — high-end European performance vehicles with proprietary diagnostic software, or very old classics requiring rare parts — may be outside what we can do on-site. We'll be straight with you about this before you book.
What if something goes wrong with the repair?
Every repair we do is covered by our 12-month / 12,000-mile parts and labor warranty. If the same problem comes back within that window, we fix it. No argument, no runaround.
That warranty also means we're invested in doing the repair right the first time. A callback doesn't help anyone.
Do you offer free estimates?
Yes. For most services, we can give you a price over the phone or by message once we know your vehicle, the symptoms, and your location. For more complex diagnostics where the root cause isn't clear yet, we'll explain what the diagnostic process costs before we start.
ReviewsWhat Our Clients Say
