DIY 1997 Volvo 855 Roll-over Valve Hose Replacement Topic is solved

[jreed]

The past few times I've tried to fill up the gas tank the pump keeps shutting off after just a few seconds, no matter how slow you try to pump in the fuel. It took me a while to finally get the tank full. This is new behavior for this car. As part of the diagnosis, I decided to check out the roll over valve to make sure that it was allowing the vapor from the tank to pass through to the charcoal canister during fueling. I had worked on the hoses about 7 or 8 years ago after a squirrel or some other critter had eaten through them, setting off a P0455 code. I had replaced the nibbled hoses and wrapped the most exposed one of them with aluminum duct tape. Here you can see the roll over valve and hoses after I removed them from the car.

Old hoses, one with duct tape "squirrel proofing" wrapped around it

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I inspected the hoses and found a hard white debris partially blocking the outlet (upper) hose. I don't know what the debris was but it looked like it might be blocking the passage of vapor. I had also used some black electrician's tape on the nipples to increase their diameter to make a better fit with the fuel line that I had used before... I suspect that the tape might have moved and partially blocked off the nipples.

Debris blocking the hose

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I noticed the roll over valve is marked "Can Vent" and has a Chrysler pentagon symbol on it... interesting. I think the charcoal canister has a "GM" label.

Chrysler symbol on top of roll over valve

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After cleaning up the ends, I tested the operation of the roll over valve by blowing through the lower pipe to verify that it was allowing air to pass and then tilting the valve on it's side and upside down to verify that it blocked the air. Then, I oriented it upright again and verified that it started allowing air to pass again.

Next I proceeded to install new hoses on the hard lines. I used 6mm ID silicone hose, which isn't the best choice for fuel vapor but it has the advantage that it can stretch -- this is helpful because the roll over valve nipples have a smaller diameter than the black plastic hard lines. The nipples are about 6mm and the black plastic hard line is about 7 or 8mm.
Outlet (upper) hard line:

Outlet hard line

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Hose installed on line:

Hose installed on upper line

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Inlet (lower) hard line:

Inlet (lower) hard line

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Hose installed on both lines:

Hoses installed on both hard lines

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Once you have the lines installed, trim the upper line to the right length and attach it to the roll over valve. To improve access, do this before you reattach the roll over valve to the car. Install a zip tie to hold the hose on the nipple.

Attach upper line to roll over valve

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Then reattach the roll over valve bracket to the car. On my car, it is a 12mm bolt:

Reattach 12mm bolt holding roll over valve bracket to car

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Then trim the lower line to the right length:

Trim the lower line to the right length

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And slide the line over the lower nipple:

Slide lower line over lower nipple

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Install and trim a zip tie to hold the lower line in place on the nipple:

Install and trim a zip tie to hold line

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Here is the completed installation:

Completed installation

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I'm looking forward to trying to fill up with fuel next time to see if this repair helps make it go smoothly.

[matthew1]

Entered into the VRD. Thanks JReed.

[smacknab]

Thanks for writing this up, do you know if the 99 has the same valve? On my car the carbon canister is back here too, by the fuel filter

[abscate]

Thanks for writing this up, do you know if the 99 has the same valve? On my car the carbon canister is back here too, by the fuel filter

Part 8 in this diagram

Part number 1255422, not showing available there but worth a google

[erikv11]

All P80 cars have that rollover valve in the back near the fuel filter.