oil trap PCV - replacement interval?

jbeebo · Post by **jbeebo** » 23 Mar 2018, 13:53

Greetings fellow masochists!

2005 S60 2.4L non-turbo w/ 180k miles. Starting to get uneven idle, and whistling sound from engine characteristic of failing oil trap - allowing too much vacuum in the crankcase, pulling air past cam or crank seals. Pull the dipstick and sound stops. Confirmed vacuum on the oil fill neck.

Alright - easy enough fix and I've done it before. This kit from FCP does the job.

But that's the impetus for this post: I've done it before, in fact 50k miles ago. Am I wrong to think that's too frequent for oil trap diaphragm failure? What else could be a) causing that oil trap to fail prematurely, or b) causing vacuum in engine crankcase?

Post by **oragex** » 23 Mar 2018, 14:10

I'd definitely replace some every 80K miles. In real life it depends on the driving habits, short drives will clog it faster that mostly highway. Having the engine idle to warm up in winter time doesn't help. Synthetic oil helps. Oil change interval is also a factor.

Do you mean the glove inflates over the oil fill cap?

Some PCV kits were not the best out there. Another factor is the lower port on the engine block: if it gets restricted and it's not cleared (removal of the oil pan), new PCV won't help.

Side note, you will need a cheap chinese oeticker clamp for those clamps, like this

https://www.ebay.com/itm/1Pc-CV-Joint-B ... 0677.m4598

jbeebo · Post by **jbeebo** » 23 Mar 2018, 15:38

so 50k replacement interval is not totally out of line. I have a long commute, 52 miles one way, and it's in SoCal - mostly it's wide open freeway 70mph. Maybe 30% of drive time it's yo-yo 0mph to 30mph. It's often hot outside, AC going. Don't seem to have a sludge problem, and use quality oils, Mahle or OEM filters and a regular 5k oil change interval.

There's vacuum in the crankcase. Recall this is a non-turbo naturally aspirated engine, which I understand fails differently than a turbo version. Mine's not as noisy as this one (not yet, the old trap was almost this bad), but this is exactly the same symptoms.

Kit I used at 130k miles was this same one from FCP Euro, which uses OEM Volvo trap, OEM hoses, etc. Last time I did not drop the oil pan, but confirmed the trap drain into the pan was open. When I removed the old trap, no oil came pouring out and the trap was light and empty. Didn't have a clogged trap then and don't think I have one now.

Question: worth dropping the pan this time so I can clean and replace oil intake seals? Didn't last time, not sure it's worth the risk.

Thanks for Oetiker clamp link, I used to have those exact ones but found them to be too soft and flexible - they bent before I had a good crimp. Bought some more sturdy ones when I did the half-shaft rebuilds.

Post by **oragex** » 23 Mar 2018, 18:24

The pliers I linked is indeed too soft but good enough for the small clamps on the PCV box. I tried it on the original VOlvo CV boot clamps and I indeed bent the arms on it

Hot weather and stop and go traffic may indeed be a factor in PCV life expectancy. In fact, none of us really knows for sure or could give technical numbers on this, so it's mostly assumptions we make.

As for the oil pan, I don't think it's needed unless indeed the lower port is clogged and no air can be blown into the oil pan, which you mention not to be the case on your car. I would not go the oil pan route, because the seals on 2001 and up were fixed by Volvo (these seals have indeed been a problem on up to 2000 cars)

Finally, the PCV box doesn't always get full with crud. Mine was also very light with no signs of oil inside at all, however the diaphragm was broken and I was getting the same whistle as yours. However - since mine is also a non turbo 2003 - the whistle noise would vanish when either I would pull the dipstick or untwist the oil filler cap, plus, what's more relevant here, I was getting some fumes by the oil dipstick (positive pressure, so different than the video) and the glove would slowly inflate when placed over the oil filler cap. With the new PCV box, the whistle is gone, no more fumes by the dipstick and the gloves over the oil filler gets sucked in quite strongly.