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Is Fix-a-Flat Dangerous?

Fix-a-Flat

The most common "tire fix in a can" product is Fix-a-Flat. Mechanics often have a love-hate relationship with this stuff. Anecdotal reports about how it can explode, catch fire, or ruin tire pressure monitoring systems (TPMS) abound. Yet officially, the company that makes the product says it isn't flammable and won't harm TPMS systems. So which is it?

First off, Fix-a-Flat will not explode or catch fire when used. This is a myth based on the original formulation of the "tire in a can" which appeared twenty-some years ago. Nothing in today's Fix-a-Flat is flammable. Neither can it explode when a technician removes the tire from its wheel after Fix-a-Flat has been used. Anecdotes of this happening are old or patently false.

Other similar products are also likely not going to cause explosions either, though it's impossible to vouch for every one of them.

What about your TPMS? Will Fix-a-Flat ruin that?

This is a bit more muddled. Most likely, it won't, if used properly. If used improperly, yes, it can, but it's still not likely to ruin the sensor, just require it be cleaned.

We checked Consumer Reports as our go-to source for testing and found that they did not find Fix-a-Flat to be a problem for TPMS. Be aware, however, that some tire shops will charge extra to clean out the tire, wheel, and sensors if you do use a product like Fix-a-Flat. You may also have to replace the valve stem.

So should you use products like Fix-a-Flat?

That depends on what you need. It can't hurt to have a can in your trunk just in case a tire is punctured but is not ruined. For small punctures in the meat of the tire, like nails, these can be a life and time saver. For serious punctures or breaks that cannot be repaired (such as sidewall impales), you'll still need a spare tire or AAA service.