Andy, Sorry for being a loser and not checking this section of the board recently, I'm always over on the Viper Discussion page. I'll clear up any confusion.
All 92-02 caps are vented. If you remove yours and blow in the nipple, you'll see that air will come through. On the underside of the cap, the "stick" portion that shows the fluid level attaches to the cap top but holes are around the base to allow air through. There is a rubber splash ring that is supposed to keep fluid from simply exiting out the hole. Venting is important in his design.
The problem is that the splash ring doesn't do a great job, especially during hard cornering of keeping the fluid in the reservior. Our product solves that. When installed, fluid is required to make it out of the cap nipple AND up another inch or so through the arch on the vent tube. This is almost impossible unless you've totally overfilled your reservoir. Even if you are tracking you Viper and fluid does make it out, the vent tube safely routes it out below the reservoir instead of on your headers.
The most important aspect of the vent tube though is the fact that is keeps the cap from turning. The stainless clamps lock onto the cap nipple with the Viton rubber seal. The cap can't turn because the tube hits the square side of the reservoir. Easy for you to pop off with small screwdriver to check/change fluid. Both reported fires were by caps falling on headers and catching fire which then in turn runs right up to reservoir and total engine is on fire.
