Your Chevy Chevelle: How to Diagnose Overheating Issues

If you have recently restored a Chevy Chevelle, you’re probably in love with this muscle car. Hearing the engine roar to life for the first time was music to your ears. You’ve taken it out for a few spins around like it’s the good ole days. But you may have come upon a very common problem with this particular classic hot rod: overheating.

These issues arise because your car from over 50 years ago is trying to keep up with modern times. For starters, the Chevelle radiator in the 1964 to 1967 models was already quite small to begin with. Also, radiator technology has greatly improved over the last few decades, so the original radiators won’t be able to help cool the car properly. Plus, overall, the cooling system could use an upgrade from the original belt-driven fan to an electric fan. On top of that, you most likely have or will in the future, want to upgrade your car’s engine upgrade, which will create even more heat.

To understand how or why your Chevelle is overheating, it helps to know when and where this is happening, as well as what kind of cooling system your may car need.

A Checklist for Your Chevelle’s Overheating Issues

If your car overheats during city driving but is cool while on the highway, your issue involves airflow. If your car overheats no matter where it is, or it overheats when you use a lot of power, then it’s the radiator.

An engine upgrade or performance modification can be the source of your problem. If you haven’t done that, then your problem is probably smaller, or you have found another part of your cooling system is starting to fail.

Tuning issues can create overheating, such as an upgrade to a fuel-injection system or a carburetor, which makes the Chevelle’s engine run more efficiently; or when the ignition timing has been altered by a few degrees. Check the ignition timing, even if you have changed it, because you may have a clogged fuel filter or some other issue that has changed the air/fuel mixture.

If your Chevelle radiator is not receiving enough airflow, you’re most likely experiencing overheating while idle or while driving slowly. The culprit is typically a missing or broken fan shroud within a belt-driven fan. The air is bypassing the radiator instead of going through it.  You may need a better fan system that can improve airflow. Finally, your radiator’s airflow may be restricted due to a damaged core.

If you go through this checklist, you should be able to solve your Chevelle’s overheating problem and be back on the road in no time.