Will Sea Foam help a 1965 Chevy summer car with 129,000 miles? [SOLVED]

Thanks for the question, Chuck.

Yes, Sea Foam can help. I’d recommend High Mileage Motor Treatment. It’s formulated as a strong cleaner for higher-mileage engines with years of buildup.

With a summer car like your ’65 Chevy, fuel gum and varnish can form while it sits. That buildup is very common in carbureted engines and is the #1 cause of things like rough running, sluggish throttle response, and even reduced fuel economy.

If gum and varnish in the fuel system is contributing to lost MPG, cleaning it up can absolutely help recover some of that mileage. When the fuel system is free from gum and varnish, the engine will run smoother and more efficiently.

Here’s what I’d do to get the most cleaning power out of a can of High Mileage:

• Wait until the tank is low (about 1/4 tank or less)

• Add a full 16 oz can of High Mileage

• Drive at least 10-20 miles (until almost empty) before refueling

The high concentration works much better and faster than adding it to a full tank.

You can also add High Mileage to the oil. Add 1 ounce per quart of oil in the crankcase, 100–300 miles before your next oil change. That will help reliquefy heavier oil residues and keep everything clean internally.