Had to replace mine at 40K while on a trip up the CA/OR coast. I knew they were wearing and called HDI to see if they would cover it under the extended warranty. The answer back was "let it develop!" So I says, "you mean they finally go out and trash the motor while I am out on some desert?" HDI says, "yes, when the engine goes we would cover its repair since it was a result of the cam chain tensioner failure, but we can't just replace them because I thought they were worn, besides they are designed to wear." Ok, so the noise is getting pretty bad and I drive it into the dealer in Eureka and the service manager says he doubts that I will make it home to Boise. He calls HDI and explained that they really were gone and needed to be changed or the cost will be a lot more if I keep driving." He got the authorization to change them out. Turns out there was an oil hole that that got plugged with the material that wears off the tensioner, which then made the tensioner wear much more rapidly then normal. Works great now and I have 70K on the engine.