small evap leak?

**albertj** · 04-07-2022, 12:40 PM

I could use some help deducing a "small evap leak" on my XC70. I think I have eliminated the leak detection pump (it's a Bosch, 2 y.o.) and the gas cap. I figure either (a) it actually is the leak detection pump and I just wish it wasn't (b) this new Volvo gas cap I put on ~18 mos ago already has issues although I seriously doubt it. (c) some clip somewhere has let go - after all the car is 15 y.o.

My next moves - ask my indie to test the cap; re-test the pump using VIDA (it seemed fine with smoke). I loaned my VIDA setup to a friend and will have it back (quite) soon.

I am going to run smoke again and peek in the fender well and elsewhere where the emissions plumbing is stuffed - maybe it's just a broken/missing clip?!?

The 'help' I need is: for those of you who have found a 'small evap leak' that was not the pump or cap, kindly chime in and tell us (me) what was it?

Thanks

Albertj

**br0dy** · 04-07-2022, 05:53 PM

Mine was on the line that goes from the purge valve to the charcoal canister. It's a hard line but theres a 6" piece of rubber flexible hose on it right before it goes into the plastic concealing "conduit". Very easy to see when you're under the car, I don't think you even need the splash shield off. It had shrunk and no longer sealed. I replaced with some 5/16" fuel line with a worm clamp on both ends. This leak also caused unfiltered air to contaminate my purge valve and caused multiple purge valve failures before I finally found it.

**albertj** · 04-08-2022, 06:19 AM

Originally Posted by br0dy

Mine was on the line that goes from the purge valve to the charcoal canister. It's a hard line but theres a 6" piece of rubber flexible hose on it right before it goes into the plastic concealing "conduit". Very easy to see when you're under the car, I don't think you even need the splash shield off. It had shrunk and no longer sealed. I replaced with some 5/16" fuel line with a worm clamp on both ends. This leak also caused unfiltered air to contaminate my purge valve and caused multiple purge valve failures before I finally found it.

Thanks! I'll check the lines (including the one you mentioned) more carefully. I looked but did not poke or pinch.

Albertj

**BrickDriver** · 04-08-2022, 09:59 AM

Mine had similar symptoms and I replaced the LDP, the purge valve, and the gas cap to no avail. I bought a smoke kit and smoked it, but couldn't find the leak. I took it to my local dealer and they smoked it and told me that the fuel filler neck vent pipe or filler neck had a leak above the tank and that it would take two thousand USD to fix. Seeing how difficult the access to this area was, I took it to a local indie to do it. He smoked it again and found a small leak, which he patched with JB Weld and I've had no problems since. Yay!
Apparently, the vent line to the canister had been rubbing the frame, which lead to a small hole in the line. I'm not sure where the hole was, but I recall him saying that it could only be seen with the back wheel off (not sure which back wheel). Sorry I can't provide more specific detail - perhaps someone has done a similar fix and can point us to the spot.
Good luck. I lived with mine for more than a year until it came time for state inspection, which gave me incentive to fix it.

**albertj** · 04-12-2022, 07:29 PM

Originally Posted by BrickDriver

Mine had similar symptoms and I replaced the LDP, the purge valve, and the gas cap to no avail. I bought a smoke kit and smoked it, but couldn't find the leak. I took it to my local dealer and they smoked it and told me that the fuel filler neck vent pipe or filler neck had a leak above the tank and that it would take two thousand USD to fix. Seeing how difficult the access to this area was, I took it to a local indie to do it. He smoked it again and found a small leak, which he patched with JB Weld and I've had no problems since. Yay!
Apparently, the vent line to the canister had been rubbing the frame, which lead to a small hole in the line. I'm not sure where the hole was, but I recall him saying that it could only be seen with the back wheel off (not sure which back wheel). Sorry I can't provide more specific detail - perhaps someone has done a similar fix and can point us to the spot.
Good luck. I lived with mine for more than a year until it came time for state inspection, which gave me incentive to fix it.

I'll check this too, thanks.

**br0dy** · 04-21-2022, 06:09 PM

Of course literally the day after I post here my p0442 comes back after a year with no CEL. Back to the drawing board....

**albertj** · 04-22-2022, 05:47 PM

Originally Posted by br0dy

Of course literally the day after I post here my p0442 comes back after a year with no CEL. Back to the drawing board....

I wonder if VIDA has some troubleshooting details about codes with no CEL?

Based on what I've seen in this thread, I think you (we - my code's back also) are settling in for an afternoon checking all the hoses and connections on the evap system, for deteriorated hoses and connections.

**br0dy** · 04-25-2022, 06:23 AM

The only useful thing in VIDA for evap leaks is the leak detection pump test which just verifies the pump’s operation so that you don’t needlessly change that. Which is always my first step and has saved me a lot of grief in that I haven’t had to experience the nightmare of replacing that.

I found my little hose on that hard line had come a bit loose so I snugged up both clamps. If my CEL doesn’t clear in a week I’ll be smoke testing the system which seems about the only effective way to troubleshoot these codes.

**v70+xc70** · 04-25-2022, 10:36 AM

Get a shop with a smoke machine to trace the leak

**albertj** · 05-25-2022, 07:55 PM

Originally Posted by v70+xc70

Get a shop with a smoke machine to trace the leak

An indie near me did that... replaced purge valve... code is back.

I'll be working on this further myself, it'll be a couple three weeks before I can get to it.