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Before I go to all the effort and expense, can anyone confirm that oil traps can go bad on an 05 XC90 2.5t? The YouTube videos and bulletin board posts I've seen all seem to relate to a much different style of oil trap, maybe for the 3.2 engine. They claim a diaphram goes bad, and Volvo recommends replacement at 100k miles. I have 133k now.
I'm looking at replacing p/n 1271988, which per Tasca and Volvopartswebstore is correct for my chassis number.
I haven't had the XC90 much more than a year, it was previously a one owner maintained and sold by the same dealer. But after getting the AWD system working again and monkeying around on a few different things like the timing belt, I'm ready for something else. It goes where ever we want it to go on trips, and my wife loves it.
Guess I'm just used to the simplicity of the 940.
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94 944 na 319,000 and still rolling - 05 XC90 2.5t AWD for the wife
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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I don't know anything about the 3.2 engine but I can tell you that the box in my 2.4 non-turbo HAS a vacuum control diaphragm which is integral to the box. So when the diaphragm cokes up and fails it necessitates the replacement of the box.
But the 2.5T has NO diaphragm or any other mechanical parts within it. So the diaphragm style may be used only in non-turbo engines??? Just a guess.
I see no reason to replace the box on a 2.5T as long as you can get it, along with all associated hoses and engine passages, thoroughly flushed out with carb cleaner or the like. There will be some crud built up inside the two ports going into the engine block. Try to carefully dig them out rather than pushing the crud into the engine block. Loosen the oil filler cap and make sure you can blow a healthy volume of air through those ports.
The achilles heal on the 2.5T PCV systems seems to be a small "nipple" fitting, as Volvo calls it. The original uses a section of hard plastic tubing that becomes brittle with age and nearly impossible to clean out without breaking it. See part #15 in this diagram (P/N 9202208):
https://www.volvopartswebstore.com/showAssembly.aspx?ukey_assembly=239388&ukey_make=865&ukey_model=12010&modelYear=2005&ukey_category=7072&ukey_driveLine=11324&ukey_trimLevel=24651
I see in the diagram that it may be somewhat re-designed from what I recall. Maybe it will now last longer before clogging up.
It bolts to the underside of the intake manifold via a banjo bolts and is the piece that provides vacuum to the PCV system. The "U" shaped tube is a coolant passage that is supposed to keep the vacuum tubing good and warm so that the crud doesn't solidify in the vacuum tubing. Once again, short haul driving is not your friend.
The 2.5T would be a fantastic engine if it weren't for the lame PCV system. So you'll have to settle for simply having a "really good" engine. :)
Good luck and sorry for the long ramble.
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Current rides: 2005 Volvo S80 2.5T, 2003 Volvo V70 2.4NA, 1973 Volvo 1800ES (STILL not road worthy!)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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@Chris Mullet, your rambles are fine with me. You've explained a great deal about the system that I didn't know, and we are all the better for it!
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94 944 na 319,000 and rolling; 05 XC90 2.5t AWD for the wife; 97 Chevy Suburban 3/4 ton 6.5 diesel daily driver; 92 745t beautiful condition (sold); 88 764t failed experiment (sold)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Have you tried the 'glove test' at the oil filler? Get the engine warm and see if the PCV is clogged.
Replacing the entire PCV is a 4 hour job, most of that taking things out that are in the way and cleaning them before putting it back. The PTC nipple is a royal pain, but when it gets clogged...
Until about 2 years ago, our esteemed dealer used conventional oil. Cheap bastard. The same might be true of the PO dealer.
\That whistle you mentioned earlier might be a diaphragm with a hole in it. OR it might be a vacuum line with a hole in it which will decrease mpg. Also check your Intercooler fittings and make sure they are all tight. Check your air cleaner for dirt and fit.
A clogged PCV does not decrease mpg. A bad O2 sensor could also be at fault.
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Keeping it running is better than buying new
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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I have not tried the glove test but read about it last night. It's to rain all week here. If I can dodge the rain drops, I'll check the glove test, nipple and other things. Vacuum lines seem to be intact, but I know visual inspection isn't enough.
All 5 plugs and one bad coil were replaced about 5,000 miles ago. Timing belt and serpentine belt were replaced shortly after 120,000 miles.
Curiously, the mpg did drop after replacing a fuel pressure sensor on the fuel rail. But we're not having the problems the old sensor gave us, like CEL and loss of power at speed on the interstate - scary! Maybe it's a wrong assumption, but I am assuming the new sensor is not at fault for our current decline of mpg.
Also got new tires right around the time mpg started dropping, but it's dropped much more than I would expect for new tires. Plus there's the whine that wasn't there before.
Thanks all for the responses. I appreciate your time. Wish I still had a garage, dodging rain drops ain't fun while wrenching.
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94 944 na 319,000 and rolling; 05 XC90 2.5t AWD for the wife; 97 Chevy Suburban 3/4 ton 6.5 diesel daily driver; 92 745t beautiful condition (sold); 88 764t failed experiment (sold)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Reactivating the AWD system and installing new tires, especially if they have an aggressive tread pattern and aren't properly inflated, could both add up to a noticeable decrease in fuel mileage. Also if the new tires are larger in circumference than the old ones then the car will be covering more ground than previously, but the odometer wont be aware of it.
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Current rides: 2018 Volvo S60 Inscription (What the heck do all these buttons do?), 2005 Volvo S80 2.5T (Soon to go bye-bye), 2003 Volvo V70 2.4NA (The family "truck"), 1973 Volvo 1800ES (STILL not road worthy!)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Will I buy another Volvo??? We'll see....
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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A quick follow-up to the original post. Glove test passed. Transmission fluid was low about a quart. I brought the fluid level up, and it does seem to be more quiet when driving.
The whine, more like a whistle than a whine, at idle may be a belt noise or pulley. The noise does not rise with the rpm or goes away with rpm. I'm not going to worry about it for now.
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94 944 na 319,000 and rolling; 05 XC90 2.5t AWD for the wife; 97 Chevy Suburban 3/4 ton 6.5 diesel daily driver; 92 745t beautiful condition (sold); 88 764t failed experiment (sold)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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The new tires and reactivating the AWD system could definitely be the cause of the lower MPG. I’ve lost 2 mpg sometimes when just changing tires. The winter gas formula could also be a factor. Also thoroughly inspect the vacuum hoses.
What puzzles me is the whine... If it were my vehicle I’d start with the tranny/AWD fluid levels and the tires. Also, are you 100% sure it has the correct fluids? As my 95 850 reached high miles it developed a slight whine in the tranny but only when decelerating. My 2002 Passat has a strange whine too. It only happens between 40-60 mph. Been there for awhile. Obviously not serious and not too noticeable or objectionable.
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Will I buy another Volvo??? We'll see....
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Good thoughts. Fillup late last week was 14.2 mpg. MPG has been steadily declining since August or September. New tires in September, and AWD was reactivated right after Thanksgiving. New fuel pressure regulator in June. Average mpg mostly in town is now 13 on the dashboard (usually correct when I check it against odometer at fillup), and it was 17 before all this. Last trip was 22 or 23 mpg and before would be 25-26.
@jwalker, you may be right that the combination of tires and awd have decreased mpg. I didn't even consider that reactivating awd would affect mpg. Xemodex did a rebuild on the DEM. I was able to confirm that everything else is in working order and within specs. A new filter, drain and refill Haldex fluid, and a lot of aggravation later, voila the awd works.
The whine developed during this time. I've not been able to isolate the source, but best guess is between the radiator and engine. It starts 20-30 seconds after starting the engine and can also be heard on acceleration. I initially thought it was the turbo getting more noisy, but I was able to rule that out.
I expected mpg to drop with new tires and reactivating awd, but not 4 digits worth.
I'll check the trans fluid this afternoon. It seems I can rule out the oil trap for now. It's not raining today, perhaps I can do the glove test this evening.
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94 944 na 319,000 and rolling; 05 XC90 2.5t AWD for the wife; 97 Chevy Suburban 3/4 ton 6.5 diesel daily driver; 92 745t beautiful condition (sold); 88 764t failed experiment (sold)
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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These responses were helpful. But then this raises a few questions. The engine has been producing a whine that rises and falls with rpm, different from the turbo whistle. And mpg has gone from 17 around town to 13.
I had just thought after hearing others post a PCV whine and poor mpg when the PCV system needed serviced that this was the case on my XC90. But if the oil trap wouldn't go bad, then my next question is whether item 15 in the parts diagram would produce these symptoms?
Frankly, I have no interest in servicing the PCV system given that it requires so much digging to get to.
We bought the XC90 at 120k miles, and I changed out fluids for Amsoil which I run faithfully in my other vehicles. So synthetic only for the last 13k miles, unless the previous owner used synthetic, I don't know. I have an oil sample ready to send off to Oil Analyzers, so this will be the first real information I get about the internal health of the engine.
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94 944 na 319,000 and still rolling - 05 XC90 2.5t AWD for the wife
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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I would focus on the nipple (part#15) as mentioned by Chris Mullett. Bet it is a lot easier to replace than the whole PCV. I really don’t know as I have owned two NA 5 cylinder Volvos but no turbos. The NA cars don’t have the infamous nipple.
Just to cover all the bases, I’d doublecheck everything. All belts good? Correct Tranny/AWD fluid and level good? Condition of the ignition parts and properly tuned with no vacuum leaks etc...
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Will I buy another Volvo??? We'll see....
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posted by
someone claiming to be
on
Wed Dec 31 18:00 CST 1969 [ RELATED]
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Personally, I have not heard of the oil traps going bad on the 5 cylinder engines. If you are going to replace the oil trap, I suggest overhauling the entire PCV system since you are going to need to remove a lot of the system anyway to replace the oil trap. On the 5 cylinder engines it is good maintenance to replace/clean the PCV system at 150-200k. So you would be doing it just a bit early...:)
Not familiar with the diaphragm you mentioned. Maybe that only applies to to the 3.2 6 cylinder engines? Other more knowledgeable folks will probably expand on this topic.
One last thought. Do you use synthetic motor oil in the XC90? That is highly recommended as it will keep the PCV clean much longer than conventional oil. The 5 cylinders really do better with synthetic oil. It is particularly important if yours is a turbo.
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Will I buy another Volvo??? We'll see....
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