Review on ACDelco RC85 Original Equipment Radiator by Jared Gopalan

Can't complain about this radiator cap (yet), but only chose it because it was the only cheap cap for my Grand Prix, which has been losing some engine coolant for a long time. When changing the coolant, I noticed that I can easily squeeze and pinch the upper radiator hose with my hand, even when the engine is warm. Considering that the system must be pressurized by one atmosphere (according to the 15psi printed on the cap), I realized the system is nowhere near holding its rated pressure. I crossed my fingers and hoped it was just a radiator cap and not a leak and I ordered this. It turns out I was right; now that the engine is up to operating temperature, the upper radiator hose looks more like a closed coca-cola bottle when i squeeze it like it should. The old one had a flat O-ring. I don't know exactly how these caps work, but I do know that o-rings are pretty cheap. If you're thinking about replacing the cap, you should measure the size of the o-ring and just replace it (it probably won't cost more than a dollar or two). My gut tells me that's the only thing wrong with my old one, but I can't say for sure. Now I'm giving the cap five stars because I can't complain about that and it was pretty cheap. But if I still have a car in a few years and this cap breaks I will definitely update the review.