Trouble while filling up your Volvo at the gas pump? Does it keep shutting off? This is how to fix it.
DIY 1997 Volvo 850 Roll-Over Valve Hose Replacement by 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.
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.
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.
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.
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.
Then reattach the roll over valve bracket to the car. On my car, it is a 12mm bolt:
Then trim the lower line to the right length:
And slide the line over the lower nipple:
Install and trim a zip tie to hold the lower line in place on the nipple:
Here is the completed installation:
I’m looking forward to trying to fill up with fuel next time to see if this repair helps make it go smoothly.