Whether your vehicle has been in a minor accident or your check engine light suddenly turned on, it’s important to check more than just the obvious. Your car’s fluids and filters play a major role in keeping systems running smoothly, and a collision or system alert could mean they’ve been compromised. Ignoring these components can lead to bigger problems down the road—especially if something critical has been overlooked.
Here’s what to inspect and maintain after a collision or a check engine warning to keep your vehicle performing safely and reliably.
Engine Oil and Filter
After any impact or diagnostic warning, checking the engine oil should be a top priority. A collision—even a minor one—can cause small cracks, dislodge components, or cause leaks that may not be visible right away.
- Check the oil level and look for any signs of leakage underneath the engine.
- Inspect the oil for unusual color or texture, which can indicate contamination or internal damage.
- Replace the oil filter if it hasn’t been changed recently or if the impact may have jarred or damaged it.
If the check engine light is tied to performance issues or misfires, dirty or old oil can be a contributing factor.
Coolant (Antifreeze)
The radiator and coolant system are often near the front of the vehicle—exactly where many collisions occur. Even a slight bump can crack a radiator hose or cause a slow leak in the coolant reservoir.
- Inspect the coolant level and check for any puddles or moisture near the front of the engine bay.
- Make sure the coolant is clean and not discolored or sludgy.
- If the engine is running hot or the temperature gauge is spiking, have the cooling system pressure-tested for hidden leaks.
Brake Fluid
If your car has experienced a jolt or triggered a check engine or ABS warning, don’t overlook the brake fluid. Leaks or air in the system can affect braking power.
- Check the brake fluid reservoir for proper level and clarity.
- If the fluid looks dark or murky, it may be time for a flush.
- Inspect for signs of leaks near brake lines or calipers, especially if the impact occurred near a wheel.
Transmission Fluid
In vehicles with automatic transmissions, hard impacts can damage transmission mounts or even affect the fluid pan. Low or dirty fluid can cause shifting problems, which may trigger a check engine light.
- Look for leaks under the center of the vehicle.
- Check fluid levels (if accessible) and ensure the color is bright red or amber—not dark or burnt.
- Sluggish shifting or unusual noises may indicate a fluid-related issue.
Air and Cabin Filters
While filters may not seem urgent, collisions can stir up debris or dislodge components that lead to blocked airflow.
- Replace the engine air filter if it’s visibly dirty or if you suspect the engine has been stressed.
- The cabin air filter should also be inspected, especially if the AC system is blowing weak or musty air.
- Keeping these filters clean improves performance, fuel economy, and air quality inside the vehicle.
Fuel System and Filters
In the event of a collision, the fuel system should always be inspected. While the tank itself is usually well protected, fuel lines and connections can be damaged.
- Look for the smell of fuel or visible leaks.
- A clogged fuel filter can also trigger a check engine light by affecting fuel pressure.
- If performance issues like stalling or hesitation occur, have the fuel system tested.
Final Thoughts
After a collision or when your check engine light comes on, checking your fluids and filters is one of the most important things you can do to protect your vehicle’s health. Damage isn’t always obvious, and small issues like leaks, dirty filters, or fluid contamination can turn into bigger problems fast. If you’re unsure about the condition of these components, schedule a post-collision inspection or diagnostic service with a trusted shop. A little attention now can save you major repairs—and keep you safely on the road.