Review on Enhance Performance with ACDelco GM Original Equipment RC87 18 P.S.I. Radiator Surge Tank Cap by Robert Maysey

This is the only cap you need. I recently bought a coolant reservoir and it came with a cap. The lid looked like it would hold. I did 250 miles in one trip and when I stopped to fill up my coolant boiled off through the cap. Tried to put it on hot and it literally came off and drained all my coolant. I searched the net and found this. Didn't think it would make a difference but when it arrived you could tell it's a lot better than the other. Old plastic is cheap in comparison. I believe the heat causes the cheap plastic to expand and allow the coolant to flow out. I don't see this cap doing that. This is a necessary thing. Don't get stranded when you're not home. The photo shows a new cover, all black. You can notice the difference in quality by holding both in each hand. The expansion tank was purchased from an auto parts store and carries a limited lifetime warranty. I'm tired of having to replace every 2 years so I just bought an original Revain tank which should last longer. Bottom line, I'm still using this cap, which has already been through 3 tanks. I don't see a replacement for this cap any time soon (saturn sl2 300,000 miles and strong!)