The 4th of July is prime car time. If you own an old car, chances are you’ll be adorning it with a flag or two and taking it out this Thursday. But will it be ready for slow-speed cruising in the heat of summer? Here are a couple of things to check before you hit the road for your local hometown parade.

1. Coolant level/leaks

This is probably a no-brainer for most of you, but let’s cover it just in case. Slow speed cooling is where most original cooling systems fail, mostly because of limited airflow through the radiator. If your car is all original and has a fan shroud, this is less of a concern. But if there’s no shroud to help direct air through the radiator versus around it, you could be in for an overheating situation after a few miles of slow-speed elbow-elbow wrist-wrist.

Be sure your cooling system is topped off and there are no leaks from the upper, lower, and heater hoses BEFORE you go. If your coolant is low, you need to know why. Finding out in the middle of the street on parade day isn’t a good plan. Look for any coolant seeping around the cylinder heads or intake manifold — leaks here mean intake manifold or cylinder head gasket issues. If your coolant is low and you can’t find any leaks, pull your spark plugs and look at them. If coolant is being burned in one cylinder, that plug will show it. If you find that’s the case, better plan on taking a different car.

Also make sure those hoses aren’t too old and soft. If they are, replace them before you go.

2. Charging system

When I was still wrenching, we’d see charging system failures twice a year: once in winter, when cold temperatures killed batteries, and again in the summer, when heat cooked them. When’s the last time you checked yours? 

Generator and early alternator systems don’t put out much amperage at idle, so you’ll want to start out with a fully charged battery. Throw a trickle charger on your car on the night of the 3rd, just to be safe. Get it up to 12.5 volts (for a 12-volt system) with the engine shut off.

If you have a multi-meter, you can check your charging system’s function by probing the positive and negative terminals of the battery while the engine is running. You should see at least 13 volts at idle, with more as you throttle the engine slightly (again, for a 12-volt system). Any less could lead to problems on the parade route. Problems here are not always cut-and-dry, from bad charging wire connections through failed regulators or corroded battery cables. As such, don’t wait to solve this on the morning of the 4th.

If all the above checks out, and you have fresh gas and full tires, you’re parade-ready. Happy 4th!

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