How to Get Fish Smell Out of a Car After a Leaky Cooler

Why does fish smell stay in a car so long?

Fish juice is full of oils and proteins. As bacteria break them down, they make a compound called trimethylamine. That is the main fishy smell. As long as there is food and moisture, the bacteria keep going.

Trimethylamine is alkaline, the opposite of an acid. That is why a mild acid like vinegar or lemon juice cuts the smell on hard plastic. But it cannot reach oil that has soaked deep into foam.

The liquid also sinks. It runs through the carpet into the padding below. Then it pools in the spare-tire well, the lowest spot in most trunks. You can scrub the top of the carpet and still smell fish a week later.

Heat makes it worse. A closed trunk warms up fast in the sun, and warm oil gives off more odor. That is why the smell seems to come back on sunny days.

What should you do right after a cooler leaks in your trunk?

Speed matters more than any product. Do these things the same day if you can.

• Put on gloves. Fish slime and old bait can carry germs.
• Take out the cooler, bags, bait bucket and anything else in the trunk.
• Blot up the liquid with old towels. Press down hard, but do not rub, or you will push it deeper.
• Leave the trunk open to air out, as long as you can stay near the car.

How do you get fish smell out of a car trunk, step by step?

This order works well for a DIY cleanup. You need gloves, towels, dish soap and a spray bottle. You also need an enzyme cleaner, a wet vac and activated charcoal.

An enzyme cleaner is a spray that breaks down the oils and proteins that feed the smell. The kind sold for pet messes works well here. A wet vac is a shop vacuum that can suck up water.

Look under the trunk floor before you add any water. Some cars, hybrids included, keep a battery, wiring or speakers there. Keep water off them, and blot and wipe near them instead of spraying.

• Pull it all out. Remove the trunk floor board, the spare tire, the jack and any foam or plastic trays. No spare tire? Lift out the foam block or sub-floor bins instead. Fish water hides in and under them.
• Wash the hard parts outside. Scrub foam trays, plastic bins and the jack with dish soap and water. Rinse and sun-dry them.
• Rinse the carpet with cool water. Spray it on lightly, then suck it back out with the wet vac. Skip very hot water for now, since heat can set proteins into the fibers.
• Spray the enzyme cleaner. Soak every spot the fish water touched, edges too. Give it the full time the label says, because enzymes work slowly.
• Extract again. Rinse lightly with cool water and pull it out with the wet vac. Repeat the spray and rinse if you still smell fish.
• Dry the spare-tire well completely. Towel it out, then vacuum up the last drops. Water left here will sour again, and salt water can start rust.
• Dry the carpet and padding. Point a fan into the open trunk, or run a dehumidifier in a closed garage. Padding that stays damp for days can also grow mold.
• Finish with charcoal. Set a bag or two of activated charcoal in the trunk for a few days. It soaks up the last faint smell. Baking soda in an open box works too.
• Put everything back only when it is bone dry. Then do a sniff test on a warm afternoon.

Where does fish water hide in a car trunk?

Fish water follows the slope of the trunk to the low spots. Check each of these places, even if they look dry.

Did a fish bag drip on a back seat instead? See our guide to cleaning cloth car seats.

Do vinegar, coffee grounds or ozone get fish smell out of a trunk?

Not on their own. Each one misses the oil soaked into the carpet and padding.

• Vinegar. It is good for hard plastic, the jack and the cooler, but not for soaked padding.
• Coffee grounds. They soak up a little odor but leave the source in place.
• Bleach. It can fade trunk carpet, and the fumes are harsh in a small space. Never mix bleach with vinegar or ammonia. The fumes can hurt you.
• Ozone. An ozone machine can help with a last stubborn trace after a full cleaning. It must run with nobody in the car, not even pets, and the car must air out well after.

Why is fish smell harder to beat in the Bay Area?

A lot of fish smell here starts with a coastal trip. People fish along the shore in Pacifica or go crabbing out of Half Moon Bay. Then wet crab pots, bait and a full cooler ride home in the trunk.

Ocean water adds salt. Salt pulls moisture from the air, so a salty carpet can feel damp again after a foggy night. Rinse salt water out with fresh water before you use the enzyme spray.

Fog is the other problem. A car parked on the street in the Sunset may stay damp for days under the marine layer. Dry it with a fan in a garage. Or wait for a sunny afternoon and stay near the car while it airs out.

Many apartment garages have no hose or outlet you can use. That is one reason people call a mobile detailer whose van brings its own water and power.

Why does my car smell like fish when nothing spilled?

First, search the car. Look under the seats, in the door pockets and under the trunk floor. A lost bait bag or a stray piece of shrimp can hide for weeks.

If you find nothing, treat it as a safety question. Overheating electrical parts can give off a fishy smell. If the smell blows from the vents when the heat or AC runs, the same rule applies. Have a mechanic check the car soon. That is a repair job, and no amount of cleaning will fix it.

How do you keep fish smell out of your car next time?

A few cheap habits stop most trunk spills before they start.

• Use a cooler with a lid that seals, and check that the drain plug is closed tight.
• Set the cooler in a plastic tub or on a rubber trunk liner. A spill stays in the tub, not in the carpet.
• Double-bag fish and bait, and tie the bags shut.
• Lay an old tarp or towel under crab pots and wet gear.
• Empty and wash the cooler as soon as you get home.

When should you call a pro for fish smell in your car?

DIY works well for a small, fresh spill that stayed on top of the carpet. Bigger spills are harder, because the smell lives in the padding and the spare-tire well.

Our technicians handle this with a Deep Interior clean. We lift out the trunk floor and trays, then extract the carpet and the spare-tire well. We treat the source with steam and enzyme cleaners, dry it, and finish with an odor treatment.

It starts at $249 for a sedan and $299 for an SUV. The final quote depends on how far the fish water spread. We come to your home, office or garage in San Francisco, the Peninsula and Marin.

Call a pro when any of these are true:

• The smell is still there after two rounds of cleaning.
• Fish water soaked the padding or pooled in the spare-tire well.
• The spill sat for days, especially in warm weather.
• The liquid reached the rear seats or the cabin carpet.
• You have no hose, no wet vac or no good place to dry the car.

Frequently Asked Questions