98 V70 gas tank - possible vapor build up issues

Post by **98v70dad** » 09 Oct 2015, 05:02

I've noticed when I fill up that I can't put the fuel fill nozzle very far into the opening or the gas pump will shut itself off thinking the tank is full. If I fully insert the nozzle as you are supposed to do the gas flow shuts off immediately every time. I've also noticed when I remove the gas cap there is a big whoosh of vapor either in or out; haven't checked which way yet.

My question is what would be causing a build up of vapors in the tank and how do I fix/replace it?

Post by **abscate** » 09 Oct 2015, 07:29

The tank traps the vapors to stop the, from going into the environment....a whoosh is pretty normal on modern cars. I also have some cars that are harder to fill at high glow gas pumps than others.

I'm not sure if you really have a problem here, has it always been this way ?

Post by **98v70dad** » 09 Oct 2015, 11:50

I'm not sure I have a problem either, but it hasn't always been this way. If I put the fill nozzle in about an inch and let all the vapors escape while filling the tank (clearly defeating the purpose) I can fill the tank. Otherwise the pump clicks off immediately.

The swoosh may be a vacuum (air sucked in as intended) or it may be blowing outwards, I need to determine which way its going. I haven't always heard this swoosh on this car and lately it seems extreme for any car. This new issue is coupled with recurring p0172 and P0440 codes even though I replaced EVERYTHING that usually causes those codes 2 years ago. The car has been code free for 2 years until now.

Just trying to figure out what might be going on.

Post by **chexny** » 09 Oct 2015, 12:05

No codes here but same exact issue here (98v70). I asked my mechanic about it and his suggestion was to just deal with it. Doesnt happen 100% of the time but definitely most all of the time. The solution is pretty straight forward and works.

Post by **scot850** » 09 Oct 2015, 13:55

Not as familiar with FWD fuel systems, but many of the V/S 70's have an air filter in the fuel system mounted up at the top of the fuel filler pipe. I don't know if there is a recommended service interval on these, but depending on where you are driving, perhaps they get blocked. Also if your car has an anti-roll over valve, these can also fail or partially fail not allowing air to exit the fuel system quickly enough when filling causing the system to 'choke'.

If you decide to replace the fuel line air filter, be careful with the old plastic protector as they are obsolete I believe (but do verify). Warming the clips may help to make the plastic easier to bend to pop out the clips holding the filter cover together.

I paid about $40 CDN for the filter (about $30 US) from my local dealer.

: Fuel system breather filter (V70 AWD)

This is the filter protector/holder on my 2000 V70R AWD.

Neil.

Post by **erikv11** » 09 Oct 2015, 14:13

I have pulled a few tank/filler neck assemblies now, nothing like that filter on the FWDs I have worked with. I learn something new every time Neil posts about AWD (and then promptly forget most of it lol)!

Post by **98v70dad** » 11 Oct 2015, 07:45

scot850 wrote:Not as familiar with FWD fuel systems, but many of the V/S 70's have an air filter in the fuel system mounted up at the top of the fuel filler pipe. I don't know if there is a recommended service interval on these, but depending on where you are driving, perhaps they get blocked. Also if your car has an anti-roll over valve, these can also fail or partially fail not allowing air to exit the fuel system quickly enough when filling causing the system to 'choke'.

If you decide to replace the fuel line air filter, be careful with the old plastic protector as they are obsolete I believe (but do verify). Warming the clips may help to make the plastic easier to bend to pop out the clips holding the filter cover together.

I paid about $40 CDN for the filter (about $30 US) from my local dealer.

Fuel tank filler neck 2000 V70R 002.JPG
This is the filter protector/holder on my 2000 V70R AWD.

Neil.

I'll have to go outside and look when I get a few minutes. I think I remember seeing a plastic housing like that on the fuel filler neck.

Post by **98v70dad** » 11 Oct 2015, 08:08

I decided to replace a couple of rubber items in the vacuum system that look rather worn that I must have overlooked a few years ago when I thought I had replaced everything.

One item is the rubber elbow on either end of a small white plastic tube. The tube runs from the vacuum tree on top of the throttle body to the aft side of the air filter box. I dont know if I can buy the rubber elbows separately or if I have to buy an assembly (tube plus elbows). I need the part number(s). I've tried to find them myself and the dealer has has tried twice for me.

The other part number is for an O-ring in the air intake. It goes somewhere in the area of flame arrester where the PCV 5/8 ths hose tees into the air intake.

Can anyone help with the part numbers?

Post by **erikv11** » 11 Oct 2015, 10:02

For the elbow to the intake, it is much easier to just replace the whole line with one piece of rubber or silicone vacuum line. That way you can just pick up what you need from any auto parts store.

Post by **jreed** » 12 Oct 2015, 04:31

If checking the roll-over valve and in-line air filter as suggested above don't help resolve the fill-up problem, I'd recommend checking the charcoal canister and the canister vent valve. Both of those must allow air to pass during fill up.