7 Mistakes You’re Making With Your Car in This Heat (And How to Fix Them)

Date: 07.03.26

The Sacramento sun doesn't play around: make sure your Kia is ready for the triple digits.

If you’ve lived in the Sacramento or Roseville area for more than a few days in July, you know exactly what "Dry Heat" feels like. It’s the kind of heat that makes the pavement shimmer, turns your steering wheel into a branding iron, and puts your vehicle through an absolute gauntlet.

At Roseville Kia, we see it every summer. When the thermometer hits 105°F and stays there, cars that weren't prepared start showing up on the back of tow trucks. The good news? Most of these summer breakdowns are completely avoidable.

To help you stay on the road and out of the heat, we’ve put together the seven most common mistakes drivers make during a Northern California summer and, more importantly, how you can fix them.

1. Waiting Until You’re Sweating to Check the A/C

We’ve all been there. You jump in the car after a long day at the Galleria, blast the air, and... it’s lukewarm. The biggest mistake is assuming your A/C is "fine" just because it worked last September.

Extreme heat increases the load on your A/C compressor and refrigerant. If your system is even slightly low on refrigerant or has a tiny leak, a 100-degree day will expose it instantly.

The Fix: Don't wait for a heatwave. Turn your A/C to the lowest setting and highest fan speed now. If it takes more than a minute to get icy cold, or if you hear a "hissing" sound, schedule a service appointment at Roseville Kia. We can perform a pressure test and recharge your system before the real sizzle starts.

Our certified technicians can spot potential cooling issues before they leave you stranded.

2. Ignoring Your Coolant Levels

Your engine is essentially a giant metal heat-generator. In the winter, the radiator has an easy job. In a Sacramento July, that radiator is working overtime. Many drivers forget to check their coolant (antifreeze) levels until the temperature gauge is in the red.

Driving with low or old coolant can lead to a warped cylinder head or a blown head gasket: repairs that cost way more than a simple flush.

The Fix: Check your coolant reservoir (the clear plastic tank under the hood) while the engine is cool. If it’s below the "Full" line, top it off with the Kia-approved mixture. If you haven't had a cooling system flush in a couple of years, it’s time to let us take a look. Fresh coolant has better heat-transfer properties than old, degraded fluid.

3. Forgetting That Heat Increases Tire Pressure

Most people know that tires lose pressure when it gets cold. But did you know that for every 10-degree rise in outside temperature, your tire pressure can increase by about 1 PSI?

On a day when it goes from a 65-degree morning to a 105-degree afternoon, your tires could be significantly over-inflated. Over-inflated tires have a smaller "patch" touching the road, which reduces traction and causes uneven wear. Even worse, if your tires are old or have "road rash," the combination of high pressure and sizzling asphalt can lead to a dangerous blowout.

The Fix: Check your tire pressure in the morning when the tires are cool. Follow the PSI numbers listed on the sticker inside your driver’s side door jamb, not the number on the tire sidewall. While you're at it, check your tread depth. If your tires are balding, they won't dissipate heat as well.

Check your tire pressure in the morning to get the most accurate reading before the heat expands the air.

4. Underestimating "The Battery Killer"

Everyone thinks winter is the season that kills batteries. In reality, heat is the silent killer. High temperatures accelerate the internal chemical reactions inside your battery and cause the internal fluid to evaporate. This leads to corrosion and, eventually, a dead battery right when you need to get home from Folsom Lake.

The Fix: If your battery is more than three years old, have it tested. We can check the "Cold Cranking Amps" and overall health in just a few minutes. Also, take a peek at the terminals. If you see white, crusty powder (corrosion), it’s preventing your battery from charging correctly. A quick cleaning or a proactive replacement can save you a huge headache later.

5. Leaving "Melting Hazards" in the Cabin

We’ve seen it all: melted crayons in the upholstery, exploded soda cans, and warped plastic sunglasses. But some items are actually dangerous. Lighters, aerosol cans (like sunscreen or hairspray), and even hand sanitizer can be fire hazards or can leak when a car's interior reaches the 140°F+ temperatures common in Roseville parking lots.

The Fix: Do a "sweep" of your car every time you get out. Pay special attention to electronics with lithium-ion batteries (like tablets or power banks), as extreme heat can cause them to swell or fail. And never, ever leave a plastic water bottle in the sun: the plastic can act like a magnifying glass and actually start a fire on your seat fabric!

6. Skipping the Sunshade (and the Tint)

Your car’s dashboard is a heat sponge. Without protection, the sun’s UV rays will eventually crack the dash and fade your beautiful Kia interior. Plus, a car that has been sitting in the sun without a shade will take twice as long to cool down once you start driving.

The Fix: Invest in a high-quality, custom-fit sunshade for your windshield. It’s the cheapest "insurance" you can buy for your interior. For even better protection, consider our ceramic window tinting services. Ceramic tint doesn't just look cool; it blocks a massive percentage of infrared heat, keeping your cabin significantly cooler even before you turn on the A/C.

A simple sunshade can lower your dashboard temperature by as much as 40 degrees.

7. Neglecting Your Transmission Fluid

When it's hot outside, your engine isn't the only thing struggling to stay cool. Your transmission generates a lot of heat, especially if you’re stop-and-go driving on I-80 or towing a boat up to the Sierra. Transmission fluid acts as both a lubricant and a coolant. When that fluid gets too hot, it thins out and loses its ability to protect the gears.

The Fix: Check your maintenance schedule in your owner's manual or via our Kia vehicle research page. If you’re a heavy commuter or do a lot of mountain driving, you might need to change your transmission fluid more frequently than someone in a milder climate. If you notice your car "shuddering" or shifting roughly in the heat, get it checked immediately.

Fresh fluids are your car's best defense against the grueling Sacramento summer.

Stay Cool with Roseville Kia

The Sacramento summer is relentless, but your Kia is built to handle it: as long as you give it a little TLC. Whether you’re driving a brand-new Kia EV9 or a reliable pre-owned Sorento, staying on top of these seven mistakes will keep you on the road and enjoying the summer.

Don't let the heat catch you off guard. Come see us at Roseville Kia for a summer multi-point inspection. Our expert team will check your battery, fluids, tires, and A/C so you can drive with confidence.

We'll help you PAY LESS, so you can SAY YES!

Jordan Rodgers, Geneeral Manager, Roseville Kia

7 Mistakes You’re Making in This California Heat