5 Car Additives for DIY Maintenance and Repairs

There are a lot of “snake-oil” car additives on the market promising just about anything you want to hear. (Want better mileage? More power?) Most, but not all, additives are a waste of money. Here are five that are actually worth using.

1 / 5

Chevron Techron Fuel Injection Cleaner

If you make a lot of short runs or drive in stop-and-go traffic, you may get better gas mileage and improve engine performance by adding a bottle of fuel system cleaner every 3,000 miles. No need to buy the expensive stuff; $15 or so should do it. Learn more about additives here.

Buy it now on Amazon.

2 / 5

Bar’s Leaks Radiator Stop Leak

 If you notice coolant puddles on your driveway, check for a cracked radiator or heater hose, or loose clamps. Then check the freeze plugs. If it turns out that your leak is coming from your radiator, try adding a cooling system sealer product. If it works, great! If not, you’ve gambled away a total of five bucks. Learn how to change your own engine coolant here.

Get this product for your vehicle now.

3 / 5

ZDDPlus Engine Oil Additive

Older engines need additional wear protection. Cars from the early-’80s or before have engines built with high-friction flat tappet lifters, which need a boost of anti-wear additive with ZDDP (zinc dialkyldithiophosphate. It costs less than $15 a bottle. Don’t use ZDDP additives with a post-’80s engine—the extra ZDDP can damage your catalytic converter.

Order this engine oil additive on Amazon.

4 / 5

Lucas Transmission Fix

If you’re driving a car with an older transmission with no shifting problems, it’s worth adding a $10 bottle of fluid conditioner. It bolsters the performance of older nonsynthetic transmission fluids. Skip it if you have a late-model car with synthetic fluid. You can change your car’s transmission fluid yourself.

Buy it now on Amazon.

5 / 5

Bar’s Leaks Head Gasket Fix

If you constantly have to top off your coolant but can’t find any sign of an external leak, you likely have a leaking head gasket. It’s worth trying a sealant before taking the car into the shop for a very expensive head gasket repair. Spend at least $25 on a quality product. It may not work, but if it does, you’ll save a boatload of money. But be sure to pay attention to the directions on the bottle! Did you know you can replace your car’s thermostat yourself? Here’s how.

Get this product today.

Disclosure: This post is brought to you by The Family Handyman editors, who aim to highlight products and services you might find interesting. If you buy them, we get a small share of the revenue from the sale from our commerce partners. We frequently receive products free of charge from manufacturers to test. This does not drive our decision as to whether or not a product is featured or recommended. We welcome your feedback. Have something you think we should know about? Contact us, here.