Cleaning Up My Used 2008 Prius

A couple of months ago I bought a used 2008 Prius with 180K mileage. Of course, like all used cars, it needed some work.

I pulled out a few dents, painted and clear coated the scratches, and installed a better battery.

On the same day I drove the car home my wife said she saw the driver side headlight switch off. At first I didn't want to believe it, but sure enough, the bulb would go out when it rained heavily. After reading about how others had solved the problem I went ahead and sealed the edges of the headlight lens using GE Silicone 2. After a few tries all the gaps were filled but the problem persisted.

The next thing I did was to replace the washer on the running lamp assembly. I used a neoprene O ring from a set I bought at our local hardware store. Then I used a hair dryer to blow air into the headlight assembly and past the opening, thus using the Venturi Effect to pull the moist air out and replace it with warm, dry air. I haven't had a problem since. HID bulbs are very susceptible to moisture, and the design of the headlights is tenuous. Too many points of failure.

The battery was 8 years old. On general principles, a stock battery lasts about 6 years. The car was throwing P0420 codes. The codes would appear during heavy rains. I read that the upstream oxygen sensor on the catalytic converter can fail so I simply pushed a dangling wire up toward the floor of the car. That seems to have helped Also, a weak battery can cause current interruptions, triggering the oxygen sensor. Long story short, the new battery seems to have solved that P0420 code problem - without replacing the catalytic converter.

I like to buy used cars. You can save tens of thousands of dollars if you just do a little work that the previous owner neglected! Toyota Prius can rack up over 300,000 miles, and at my age this may be my last. By doing a few things I can maintain the car for at least ten years. Now I have a great touring car in the best condition one could imagine. I saved a LOT of money. The battery was the only large expense at roughly $150. When I installed that new Optima Yellow Top battery all the displays looked brighter. I hear they have at least double the life of the Toyota stock battery. The battery can cause reduced mileage because the engine is harder for the system to start when needed. A deep-cranking battery removes this problem.