DIY 1997 Volvo 850 Roll-Over Valve Hose Replacement

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.

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.

OLD HOSES, ONE WITH DUCT TAPE “SQUIRREL PROOFING” WRAPPED AROUND IT

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

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

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 Hose installed on line.

HOSE INSTALLED ON UPPER LINE Inlet (lower) hard line

INLET (LOWER) HARD LINE

HOSES INSTALLED ON BOTH HARD LINES

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.