I have a 1998 S70 GLT. 9 months ago the CEL came on for code P0440. I replaced the canister purge valve and the problem went away for a while. About a month ago the CEL came on for P0440 again. I thought 9 months was a little short for the purge valve to last, but I checked it and it didn't hold a vacuum, so I replaced it. Now just a week later, the CEL came on again, again for P0440. I checked the new purge valve and now the new one doesn't hold a vacuum. The car runs fine; no change in behavior.

I don't think it's related, but 2 months ago I noticed oil was being forced out where the turbo oil return line enters the oil pan so I replaced the gasket and o-ring like it says in Bay 13.

I there something else that could be wrong with the car that could be damaging the purge valves? Could the turbo oil return line repair be related?

I checked for a vacuum using a rubber squeeze bulb from my Prestone anti-freeze tester. I removed the purge valve from the car, squeeze the bulb, pushed it onto the purge valve, and released. I did this when the valve was brand new and it held a vacuum. Was that a good way to test?

Thanks,
Dave

Obviously something is causing this problem and it isn't your purge valve. In fact that and possibley the turbo "o" ring may be the symptoms of other issues. I would first check all of your Positive Crankcase System hoses and elbows as well as flametrap (if your car doesn't have one, there are still hoses that act the same way) which can get clogged up and cause blow-by from built up pressure. What you don't want is the rear main seal going due to this problem. If your not confident in figuring all of this out, take it to a good indy mechanic.
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1998 S70 T5 Emarald Green Metallic, 2004 V70 2.5T Ruby Red, Previous Owner of Black '94 850 Turbo Wagon