DIY 1997 Volvo 850 Roll-Over Valve Hose Replacement

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.

California Relaxes OBD-II Smog Test Readiness Requirements

MVS Forums Moderator abscate made an interesting post about OBD-II readiness states during state smog emissions testing. It turns out that recently (2015 for California) some states have relaxed their rules about passing/failing cars without all monitors in the readiness state. Yes, this is technical nerdery that can cause you (or used to cause you) […]

S90 Intermittent Hesitation At Low Rpms

MVS Forums member bloodrootfc asks, then answers, a question about diagnosing intermittent hesitation on his Volvo S90 sedan: After getting fed up with “try this” from 4 mechanics, I started doing my own diagnostics with a Torque app and scan tool, and calling the shots. My mechanic works faster than I do, and he does […]

V70 P0455, P0440, P0442 Fix w/ Photos

Finally got fed up with the host of evap codes on my 1998 V70 AWD and went ahead and replaced the canister hoses, rollover valve hoses, purge valve (and surrounding hoses), and the three inches of rubber line connecting the small vent filler tube to the hard plastic line coming from top of fuel tank. I didn’t order any special hoses, rather went to Autozone and bought a variety of molded J and U hoses (they were kind enough to let me go the back and pick out what I needed).

How to Test and Repair your EVAP Valve


The purge valve is a common failure item on the Volvo 850/x70 series. This is a great how-to with easy-to-follow pictures for a fix to avoid buying a new valve. I have adapted this from my original tutorial for the BMW M30 engines. They both use Bosch systems and the valve is identical. What happens […]