Seasonal Maintenance for EMS and Fire Fleets

If you’re in EMS or fire, you already know the deal: your vehicles don’t get a vacation. They run through salt, heat, potholes, thunderstorms, road debris, and the occasional possum. Every season brings its own brand of abuse, and most rigs get just enough attention to survive it — not to handle it.

Here’s how the seasons actually mess with your fleet, and what you should be checking before something breaks and leaves you stranded mid-shift with a patient, three firefighters, and a transmission that sounds like a blender full of rocks.

Spring

AKA: The "Let’s Find Out What Broke in Winter" Season

Winter’s over, but the mess it left behind is still bolted to your chassis. Time to dig in and undo some damage.

✅ Test the batteries.
Cold kills batteries, but they usually wait until spring to die in the most inconvenient parking lot possible.

✅ Wash the undercarriage.
You’ve been bathing your suspension in salt for three months. Wash it off before it eats through your brake lines.

✅ Check the paint.
Rust doesn’t sleep. If the paint’s bubbling, flaking, or mysteriously gone — deal with it now.

✅ Weather seals.
You’d be amazed how much water can sneak in through a cracked door seal. Then it freezes. Then it breaks stuff.

✅ Exterior lights.
Moisture, salt, and vibration — it’s like a spa day for electrical failure. Look for fogged lenses or flickering LEDs.

Summer

Heat, road debris, and that weird smell coming from the cab HVAC

Summer doesn’t care that your fleet is already tired from winter. It just turns up the heat and adds a few roofing nails to the road for fun.

✅ Check the coolant.
If it’s low or gross, your engine’s going to roast. Overheating on a call? Not a good look.

✅ Test the fan.

• Mechanical: Engine off, spin it by hand. Should be some drag. Spins like a windmill? Fan clutch is cooked.

• Electric: Turn the rig on, crank the A/C. Fan should kick on. If not, grab your wallet.

✅ Tires.
Hot pavement + underinflated tires = kaboom. Bonus: summer construction means more debris, so enjoy that free nail collection.

✅ Transmission fluid.
Heat destroys trans fluid. Old fluid looks like coffee, smells like death. Change it before it changes your plans.

✅ Cabin air filters.
Blower weak? Vents blowing warm air? Might not be the A/C — could just be a filter full of pine needles and mystery fuzz.

✅ Check electronics fans/inverter vents.
If it makes power or cools something down, make sure it’s not clogged up with dust, hair, or whatever that fuzz is behind the bench seat.

Fall

The calm before the saltstorm. Get your act together.

Fall is when you do all the stuff you meant to do in the summer but didn’t. It’s your last window before everything starts freezing and breaking for no reason.

✅ Undercarriage wash + re-coat.
Start clean. Hit it with undercoating. You’ll thank yourself in February.

✅ Test the heat.
Go ahead, fire it up now — before your next shift starts with a freezing crew and a heater core that’s MIA.

✅ Lubricate all your exterior latches.
Use CorrosionX HD. Not WD-40. Not axle grease. The good stuff. Do not lube the chassis latches unless you enjoy doors that stop working.

✅ Manually check every latch.
Spraying it isn’t enough. Open it. Close it. Slam it. If it sticks, fix it before it freezes shut.

✅ Belts and hoses.
If they’re cracked, brittle, or shiny — they’re done. Replace them.

✅ Brakes.
Marginal pads today = poor stopping on snow tomorrow. Fresh brakes stop better. Pretty simple.

✅ Tires.
Yes, again. Because balding tires on snow are a lawsuit waiting to happen.

Winter

The season of “I didn’t think that could freeze.”

Everyone’s checking their fluids and plugging in the block heaters. Great. Now here’s what most folks aren’t checking — and should be.

✅ Door handles and locks.
When they freeze, they snap. Open and close every door before they need to be opened with a pry bar and a bad attitude.

✅ Power steps and ramps.
These things love to bind when it’s cold. Test them before your next patient ends up climbing in sideways.

✅ Compartment lights and switches.
Cold + moisture = weird flickering, non-working switches, and late-night troubleshooting you don’t want.

✅ Air system (if equipped).
Drain the tanks. Ice in your valves = air suspension that won’t rise or brakes that don’t release.

✅ Scene and perimeter lighting.
Old, brittle wires love to crack in cold weather. Check everything before your next nighttime call turns into a flashlight dance.

Final Thoughts From the Wrench Side

Your fleet doesn’t take sick days. But you know what it does take? A beating — every single season. Stay ahead of it, and your crew stays safe, your calls go smoother, and your budget doesn’t get blindsided by $3,000 electrical repairs that could’ve been prevented with a can of CorrosionX and 20 minutes.