98 V70 NA 139000 miles - Diagnose charcoal canister as OK

Post by **98v70dad** » 13 Jan 2016, 20:21

How can you tell when the evap canister is done absorbing gas fumes(no longer funtional) and needs to be replaced?

Post by **abscate** » 14 Jan 2016, 04:05

They don't really wear out unless you fill It with liquid fuel by overfilling the tank grossly. If you don't think it's working a PnP is An ideal solution.

Post by **98v70dad** » 14 Jan 2016, 05:31

abscate wrote:They don't really wear out unless you fill It with liquid fuel by overfilling the tank grossly. If you don't think it's working a PnP is An ideal solution.

Having fluid in it is what I'm concerned about. I have routinely overfilled the gas tank for years in order to avoid having to stop at the gas station twice a week. That extra half gallon makes the difference. At the time I didn't know better.

When fueling my car the gas pump shuts off immediately. I suspect that the fumes aren't being removed from the tank. Both the purge valve and the shut off valve are pretty new (less than 2 years old) and they are both volvo OEM parts. I have never suspected the charcoal canister in the past but lately I've been wondering about it. Last time I had it off (about 2 years ago when I replaced all the PCV hoses, purge valve and shut off valve) it did not have any fluid in it.

I know I can remove the canister and see if its heavy, but I was trying to avoid having to do that.

I don't know of a good PnP near me in Atlanta. We may have one but I don't know where it is....I guess I ought to search for one There used to be one pretty close to my house. I was a frequent customer. They closed it and cleaned up the site. Most places have the parts already removed and on the shelf in a warehouse at a higher cost.

Post by **cn90** » 14 Jan 2016, 08:27

I always fill the tank about 1 gallon short of FULL to avoid this issue.
For ex, if I am at 1/4 tank, and I know it takes another 14G to get to Full, I fill with only 13G.

On youtube, there is a guy rebuilding his charcoal canister by removing the lid, empty old activated charcoal, fill with new, then seal the lid with black RTV sealant.

And of course, you can get a junk yard canister.

New Volvo OEM is about $200.

Post by **98v70dad** » 14 Jan 2016, 10:05

cn90 wrote:I always fill the tank about 1 gallon short of FULL to avoid this issue.
For ex, if I am at 1/4 tank, and I know it takes another 14G to get to Full, I fill with only 13G.

On youtube, there is a guy rebuilding his charcoal canister by removing the lid, empty old activated charcoal, fill with new, then seal the lid with black RTV sealant.

And of course, you can get a junk yard canister.

New Volvo OEM is about $200.

Easy enough to avoid overfilling unless you are doing it on purpose. Before I knew better, I did it on purpose. I live in metro Atlanta and my commute (one direction) routinely takes up to an hour and a half. If its raining it takes longer. If there is a ball game it takes longer. The record for me is 3 hours if you don't count snowmaggedon a few years ago. On that day I left work at 11:30 AM and got home at around 2 AM THE NEXT DAY. I had to walk the last 2 miles because I had to abandon my car due to the road being impassable due to wrecks. I am from Chicago. Atlanta traffic is just as bad or worse in my opinion.

Anyhow the practice of overfilling freed up a little time for me on work night evenings by shifting the need to fill up to a saturday or sunday. Now I know better and don't do it anymore.

Post by **abscate** » 14 Jan 2016, 11:02

Are you getting a huge whoosh when you open the tank? If not, I would leave it alone - its probably doing its job.

Post by **98v70dad** » 14 Jan 2016, 11:29

No woosh. But before I replaced the purge valve for the second time I did get a huge woosh. After replacing the purge valve the second time with an OEM part the woosh stopped and so did the immediate gas pump shut off when doing a fill up. The purge valve was replaced to eliminate a P0455 code which id did successfully. Its been about 3 months now and P0455 is back, the woosh is still gone but the gas pump shut off problem is also back. I'm replacing the tapered rubber vent tube on top of the tank this weekend if I have time. Other than the evap canister and the fuel tank pressure sensor it is the only other possible problem in the PCV system (that I know of) that has not been upgraded to new.

Post by **theWIFES_S70** » 25 Jan 2016, 18:51

I came across this video today, https://www.youtube.com/watch?v=6qmLp-cJeCk, and was wondering if there's a breakdown of our charcoal canisters somewhere on this forum. Is there activated charcoal and foam like in this MGB? Is its purpose to absorb gasoline overspill and fumes? If so, it would stand to reason that if the charcoal is no longer working (i.e., has already absorbed all the gasoline and vapors it can possibly absorb) than perhaps if all the lines are new, maybe the computer would register a P0455, no?

Post by **sleddriver** » 25 Jan 2016, 19:10

I tested mine for both pressure and vacuum leaks using a small airbrush compressor. You could also do it with an aquarium pump.