Is it safe to use pure isopropyl alcohol as a...

Dear Car Talk

Dear Car Talk | Dec 01, 1994

Dear Tom and Ray:

Is it safe to use pure isopropyl alcohol as a gas line antifreeze? We have been using NAPA gas line antifreeze, which says it contains 99.9% isopropyl alcohol. A 12 ounce container of NAPA costs me $1.07. Pure isopropyl alcohol is 39 cents a pint in my local drug store. Can I use that instead?

RAY: Sure you can. If you have a fuel injected car, isopropyl alcohol is the recommended gas line antifreeze (methyl alcohol is recommended for carbureted cars).

TOM: In both cases, the alcohol absorbs moisture that condenses in the gas tank and fuel line. And if you really feel you need this stuff (we never use it ourselves), you can use the isopropyl alcohol in the same ratio recommended on the NAPA bottle (about 12 ounces to ten gallons of gas).

RAY: And for a third of the price, you've got 99.9% of what's in the NAPA bottle. The other 0.01% is a secret ingredient NAPA throws in. We haven't been able to confirm this, but highly-placed sources tell us it's desalinated prune juice.827

Get the Car Talk Newsletter

Got a question about your car?

Ask Someone Who Owns One