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I have a 71 C3 that is in very good condition but I’m having an ongoing issue with gas leaks with the EVAP valve that mounts to the side of the tank. Gas leaks out from the valve, runs down the side of the gas tank and drips on the top of the muffler....not good.
I’ve personally dropped the tank twice and replaced the valve but still have gas leaks whenever the tank is ½ full to full. (Full is 1” below the base of the filler neck).
The car is back for a second time at a well-respected vintage repair shop, still leaking gas after their repair. The work done at the shop was replacement of the EVAP valve, replacement of and rerouting gas lines, blowing out the line to the EVAP charcoal canister.
It resumed leaking after just two weeks of bringing it home.
Anyone experiencing EVAP valve leaks?
Seems there are no good quality OEM replacements, only cheap plastic junk.
I’ve personally dropped the tank twice and replaced the valve but still have gas leaks whenever the tank is ½ full to full. (Full is 1” below the base of the filler neck).
Anyone experiencing EVAP valve leaks?
Seems there are no good quality OEM replacements, only cheap plastic junk.
This last sentence is on the money. There are currently no good quality replacements for the fuel separator valve. Good thing you mentioned you still have the problem with 1/2 tank of fuel, otherwise you'd have everyone claiming your problem is that you don't know how to fill up the gas tank. Ask me how I know.
As mentioned in that thread, I suspect the problem is either with the ethanol in today's fuels and/or manufacturers have cut corners with the thickness of the material and the quality of the seams. Most of the valves that failed on me had the sides collapsed to the point the float inside was being captured and not allowed to move freely. I suspect the collapse of the sides also led to the seams opening up on those valves that leaked.
If your leaking fuel with 1/2 tank it should not be leaking from the EVAP check valve. That fuel tube is almost at the top of the tank unless you are parked with the car at a steep angle toward the front or left side of the car. Sound like the tank seam maybe the cause of this leak.
If your leaking fuel with 1/2 tank it should not be leaking from the EVAP check valve. That fuel tube is almost at the top of the tank unless you are parked with the car at a steep angle toward the front or left side of the car. Sound like the tank seam maybe the cause of this leak.
Certainly possible to be a tank leak but I can tell you from experience that driving aggressively with less than a full tank will definitely slosh fuel into the vent line.
Also very possible to be a hose leak, if the hose is old or not the correct size or not clamped to prevent leakage. The tank fitting could be damaged, cracked, etc as well.
EVAP Gas Leak
