O'Fallon Auto Repair

We’ve all heard it before: "Oh, I know a guy who can do it cheaper!" And while saving money is great, when it comes to your car, trusting the wrong "guy" can lead to catastrophic—and expensive—consequences. Recently, we had a customer in O'Fallon whose well-meaning friend replaced her spark plugs. Unfortunately, he didn’t torque them properly. The result? The spark plug backed itself out, compression blew it clean out of the head—and took the threads with it. Now, instead of a simple spark plug change, she’s facing a costly cylinder head repair. The Perils of Improper Repairs This isn’t an isolated incident. With the deadly heat wave we’re enduring in O'Fallon, we’ve seen cars overheat because "their guy" used improperly mixed coolant. We’ve had vehicles towed in with engines overfilled with oil (hello, blown seals!). We’ve even seen brake pads installed ... read more

Manual transmissions are built to last—but only if you treat them right. Unfortunately, many drivers (even self-proclaimed "car enthusiasts") unknowingly abuse their gearboxes with bad habits that lead to premature wear, grinding gears, and costly repairs. At Hillside Auto Repair, we’ve rebuilt enough transmissions to know which mistakes are most common—and how to avoid them. In this post, we’ll cover: ✔ The top 5 manual transmission mistakes killing your clutch and synchros ✔ How to extend the life of your gearbox (proper shifting, maintenance, etc.) ✔ Why DIY fixes often make things worse (and when to call a pro) 5 Manual Transmission Mistakes That Lead to Early Failure 1. Riding the Clutch (The Silent Killer) The Mistake: Resting your foot on the clutch pedal while driving. Why It’s Bad: Even slight pressure can cause the clutch to partially engage, leading to: Premat ... read more

Modern engines are marvels of efficiency, but carbon buildup can rob them of power, fuel economy, and smooth operation. That’s where induction cleaning comes in—a professional service that restores your engine’s performance by removing harmful deposits. Recently, a customer asked us: "Why do I need an induction cleaning? Can’t I just do an Italian Tune-Up?" Great question—and one that deserves a thorough answer. In this post, we’ll cover: ✔ What induction cleaning is and why it’s critical ✔ Why the old-school "Italian Tune-Up" doesn’t cut it ✔ Signs your engine needs an induction service ✔ Why DIY methods can be risky (and when to call a pro)   What Is Induction Cleaning Induction cleaning is a professional service that removes carbon deposits from your engine’s intake valves, throttle body, and combustion chambers. Over time, fuel a ... read more

Your engine is a symphony of controlled explosions—but when the timing is off, it can sound more like a chaotic drum solo. Pre-detonation (engine knock) is one of the most destructive issues an engine can face, and if left unchecked, it can lead to costly repairs. What Is Pre-Detonation? Pre-detonation (also called engine knock or spark knock) occurs when the air-fuel mixture in the combustion chamber ignites too early—before the spark plug fires. Normally, combustion happens in a controlled burn, but pre-detonation creates multiple flame fronts, leading to violent pressure spikes that hammer your engine’s internals. Think of it like trying to push a swing at the wrong time—instead of smooth motion, you get a jarring clash of forces.   What Causes Pre-Detonation? Several factors can trigger knock, including: 1. Low-Octane Fuel Using regular (87 octane) gas in a high-compression ... read more

Imagine your car’s engine is like a human body—and oil is its blood. Now, picture driving with a massive oil leak like trying to run a marathon with a slit wrist. Sure, you might make it a few more steps, but eventually, you’re going to collapse. Recently, a customer called us wanting to drive her car in despite it hemorrhaging oil. She figured, "It’s still running, so how bad could it be?" The answer? Catastrophic engine failure bad. In this post, we’ll break down: ✔ Why oil is your engine’s lifeline (it’s not just about lubrication) ✔ What happens when you run out of oil (spoiler: it’s expensive) ✔ Why you should NEVER drive with a severe leak (tow it instead!) ✔ The risks of DIY oil leak repairs (and why pros do it better)   Oil Is Your Engine’s Lifeblood—Here’s Why Oil isn’t just there to keep parts sl ... read more