Dear Tom,

I own a 2004 Chrysler Pacifica with 87,000 miles. There is a green liquid on the floor of my garage and I think it might be anti freeze. Can I add that stop leak stuff to it? Will it work? What happens if I don't fix the leak?

Sharon from Memphis, TN


Based on the color of the fluid it is probably anti freeze leaking from the cooling system. Do NOT put stop leak in the cooling system! Get the vehicle into a shop and have the cooling system pressure-tested for leaks and repair if needed. If you ignore the problem, you could face major engine damage down the road.


Questions and concerns about fluid leaks are quite common. It's a topic worthy of more in-depth consideration, since some leaks can result in major damage and costly repairs if they go unattended and/or the solution to the problem is shortsighted.

Sharon's Chrysler Pacifica comes from the factory with a coolant called ethylene glycol, which is green in color. Some carmakers use a long-lasting antifreeze that is orange in color. If your car uses this coolant and you see an orange fluid on the ground, it could be engine coolant, which is also orange.

Can I add that stop leak stuff? Will it work?

Engine coolant stop leak can and does stop small leaks, but it is a shortsighted solution. As the leak grows the stop leak becomes ineffective. Stop leak typically clogs small coolant passageways in heater cores and radiator tubes. I have seen so much stop leak installed in engines that it actually stopped up water jackets (the water passageways around the cylinder walls). Stay away from this product because it can and does cause more trouble than it fixes.

What happens if I don't fix the leak?

Cooling system leaks only get worse with time. The more coolant lost the hotter the engine gets; the hotter the engine gets, the more likely major engine damage will occur. So, fix it: it's cheaper down the road.

Fluid Colors To Watch Out For:

Red Usually power steering or transmission fluid
Carmel Engine oil
Clear A/C condensation
Clear translucent Brake fluid
Black Gear oil

If I see these various fluids leaking on the ground, should I simply add more?

Adding more fluid is okay. The proper level of whatever fluid is leaking should be maintained because a low fluid level typically results in failure of the system if ignored. However, you need to find the cause of the leak and repair it before serious damage is done and you have to face costly repairs or safety issues. For example, if brake fluid is leaking and the system is allowed to drain, then the brakes will not work, putting you at risk of an accident. If the transmission fluid is too low, friction increases which can cause internal failure and permanent damage to the transmission.

If I see a leak, how to I do I find the source?

Typically, a novice cannot track down and repair a vehicular leak. Systems are difficult to get at and present quite a challenge for the DIY'er.

How do professional techs track down fluid leaks?

Pressure testing: During this procedure air is injected into the vehicle's closed cooling system in an effort to force a coolant leak at the weakest point in the system. When a leak springs, you have found its source and can then repair it.

Dye testing: During this procedure the tech adds a small vial of fluorescent dye to the system he/she is testing. For instance, if the engine or transmission is leaking oil, and the leak continues to avoid detection, the dye is installed in the part that is leaking. The part is then cleaned of all leakage and the vehicle is driven for a few days. At this point the tech will shine an ultraviolet light on the part. A bright yellow color will appear in the area where the fluid is leaking. This is a very effective test for tracking down stubborn leaks.

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