I've been runnin since a few days after I bought this 99 new with no isolator. I'm on the 3rd guage since then and it sits outside mounted on the hood. The first one leaked the fluid out of the guage area but still worked, I changed it out anyway just to be sure. The 2nd one I changed while I was changin some fuel lines out for the same reason, just because. I run the cheapest ones I can find so I can't even say it's because of the high quality. The current one cost me almost $20 and it was the most expensive one of the three.