TorchRedRocket

So, I ended up getting a new cap from NAPA, and my problem looks to be solved. It's been about 4 weeks since the new cap has been on the car and no signs of seepage! I was initially worried when I opened up the package and the cap didn't come with a new rubber gasket, but I thought, oh well, I'll try it anyways. I put my existing rubber gasket in the new cap, screwed it on, and I noticed right away that it fit a lot tighter on the reservoir, and the rubber really sealed it shut more tightly than when it was in the old cap. Makes me wonder if the cap that was on my car was the wrong size? Anyways, thanks for the advice!

Baldfart

Nice. I have only my C5 for a month now, but this is one of the things I have noticed that needs a fix on my car. I am going to give this a shot.

sarrojm

Thanks to this forum, replaced mine with a NAPPA cap and problem solved. The fluid did eat away some paint on the black housing behind the reservoir

TorchRedRocket

Did the rubber gasket come with your cap?

sarrojm

The rubber gasket did not come with the cap. I used the old one.

Tigershark3

Mine leaked as shown... new gasket for the cap solved the problem - no need to get an entire cap. Advance Auto or Autozone should have one for a few bucks. Cheapest repair to date on this car.