1998 Volvo V70 Emissions Code P0442 - minor leak

[scot850]

I have gone on about this before. Car has emissions code #3 with the rectangular carbon filter under the front LH fender forward of the wheel.

Owner previously swapped the fuel cap to try to fix the issue. I still have to check this as I did have a problem with another P80 and it was not actually the cap but the top edge of the fuel filler neck that had been dinged badly preventing a good seal.

I have checked and swapped the emissions valve under the hood with a good used one as well as the hoses to the carbon filter and the other end of the valve to the intake.

Also checked the exhaust valve under the LH inner fender and also tested good.

Only thing left to check is the pipe that runs from the carbon filter to the back of the car.

Q) On FWD cars where does this pipe go to? Also is there a roll-over valve on these cars? If so where is it?

Any other suggestions for possible leaks?

Thanks,

Neil.

[MoVolvos]

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Put a piece of clothing in the filler neck, no smoking and sand the filler neck inlet of dirt and grime with a pad or super fine sand paper in a circular motion. Clean the O-ring on the cap with alcohol then lubricate with silicone grease. This reduce the same code on our 08 C30 by more than 85% perhaps . Need a cap really but a good indicator what is triggering the code.


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[MoVolvos]

the top edge of the fuel filler neck that had been dinged badly preventing a good seal.

Any other suggestions for possible leaks?

Thanks,

Neil.

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Find a coupe small but thick rubber bands and wrap it around the middle of the seal so it protrudes forward. This may help seal the gap in the ding. Again, trial and error in this case to find the cause of the code.

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[scot850]

Appreciate your input on this. This is what I did last time I had this issue, but I did not use the alcohol. The rubber band idea is also a great one. I'll update when I can get my hands on the car again to try this.

Thanks,

Neil.

[scot850]

So I have replaced the emissions valve by the radiator with another used one, replaced the pipes on the carbon filter as well as the pipe to the vent valve on the RH inner fender. Also cleaned and tester the valve.

I also cleaned and sanded the fuel filler neck, fitted a brand new Volvo fuel cap and even used a little vaseline on the seal for a week to see if any of this would fix this issue, but no. All that is left it the pipe that runs from the carbon filter to the back of the car. I think this runs back to the roll-over valve? Where is that situated and any other ideas? The fun of chasing this is running thin. May have to try having the system smoked as this is beating me!

Neil.

[jreed]

My 97 gave this code when the pipe connecting to the roll over valve was nibbled by a squirrel or some other creature. The roll over valve (at least on the 97) is near the fuel filter at the rear of the car.

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[scot850]

Awesome help as usual! I will have the wheels off this weekend when swapping the tires and giving the brakes and suspension a look-over. This will give me better visibility.

Great write up too!

Neil.

[abscate]

The rollover valve is in the fuel line supply, not the emission vacuum and vent line. It prevents fuel from running out of the tank in the Month of June.

The canister shut off and purge valves are the two that can give P04xx codes. Leaky lines and hoses are 10x more likely than bad valves.

Corrected

[scot850]

Ah, good point! I have checked or swapped the 2 valves at the front, but there is a pipe that runs to the rear of the car, one of those 6mm plastic hard pipes. Where does that go to?

Neil.

[jreed]

My memory is that the rollover valve is connected to the tank vent line. The purpose of the rollover valve is to block the vent line if the car rolls over, to prevent liquid from running out of the tank.
The tank vent line runs from the tank up to the purge valve at the front of the car.