Patches

I have had this issue since day one - after a period of 45-60 minutes of steady-state highway driving, I will start to hear a very distinct clicking sound. One single loud click every several seconds that sounds like it's coming through the firewall. I remember conversing with a forum member about 4 years ago with the same problem and a mechanic he knew well said "it was something about a small amount of oil gets in EVAP Canister Purge Solenoid Valve and it starts clicking. He said if you downshift and raise the RPM, it purges itself and then stays clear for awhile."

I was out for a long drive today (68 deg. in southern Indiana ) and heard the clicking noise again. Haven't heard it in quite some time. My wife was with me and commented on it as well and she rarely notices car noises. I had to stop for gas and when we got back on the highway, the clicking was gone.

I never did hear from that member if there was any other resolution for this issue. It doesn't affect performance. Anyone here got a clue what this is?

madeouttaglass

Ed, I've done plenty of multi hour, steady state highway driving in the C5. I'm fairly good at catching odd sounds in any of our vehicles, usually with a 2 second, "Oh crap" 100 item runthrough of what it could be. I can't say that I've ever heard what you're describing.

Patches

Hey, Tom. Funny thing is, I didn't hear it at all when I made the 400 mile drive from Atlanta when I moved here. Seems more coold/cool weather related as I don't rmember hearing it in the warm summer months.

madeouttaglass

I'm sorry that I'm no help here, but a few more posts always helps in getting others to look at a thread. I've driven my car in temps from below freezing to near 100 without ever hearing that sound.

Patches

So, anyone experienced / heard of this phenomenon?

vettenuts

Haven't heard it but have to admit I am puzzled how oil could get in there to start with. Vacuum is on intake side and EVAP canister on the other.

Patches

I agree. It does have me wondering though since it is attached to the intake, so it seems somewhat plausible that oil could be involved. I need to pull it off and examine it closely this coming week since I am off work. If I find any traces of oil the above thory may have some truth to it. Geez, hope I don't need another friggin' catch can.

vettenuts

Too bad you didn't have Autotap running when the noise came on, you could check the percentage and tank vacuum numbers to see if something goofy was going on.

Patches

Good idea. If the weather holds next week, I'll take her out for awhile and log an EFI session and see if I can get it to happen.

Jeremi Stanford

i dont have a corvette but i have a 2000 jeep grand Cherokee Laredo that is doing the same thing the evap canister under the hood is clicking at first i thought my engine was knocking if i unplug the evap solenoid the noise stops i have now mil/cel light on i think its normal its been doing it for years so i dont know it just passed inspection my jeep runs great and i get 14mpg city and about 18 highway i would like to know how to fix the issue but i accepted it as normal its done it since i bought the vehicle when the hood is closed and radio is on cant hear it but if you listen closely you can hear it with hood closed.