2005 XC70 Burning Oil

[shin91]

Hey guys,

Hope this finds everyone well.

My 2.5T 2005 Volvo XC70 is a lovely car with 133,000km and has been burning oil at a rate of about 1 quart per 1,500km.
I bought it second hand at 123,000km and as far as I can tell from the receipts, it has been serviced yearly/15,000 km intervals with Mobil 1 fully synthetic 10w40 High Milage.
We changed the oil grade from Mobil 1 10w30 to Mobil 1 10w40 High Milage after I found that it was burning oil so profusely and also because of the Australian summer which commonly hits 40+ degrees celcius.

There is no leak under the car or on the ground where I park it.
No smoke from the exhaust at ignition or whilst driving.
No oil splattered on the engine.
No white deposits under the oil cap.

1. My independent mechanic believes its the turbocharger ($2000+)
2. Dealer thinks its a partially blocked breather box (from the research I've done on the forum I'm guessing that this is the PCV system? please confirm) and replacing this will be $900. They have written on the invoice to "replace soon."

At this stage, after reading on the forums and research I'm leaning toward getting the breather box replaced by the dealership.
Could anyone give me some more insight and kind words before I pour some more money into my beloved Volvo?
Any way to confirm?

Not confident and do not have tools to DIY - would like to leave to a pro.

Thanks for your time and have a great day.

[JRL]

Breather is probably clogged, 10,000 miles is WAAAAAAAAAAAAY too long for an oil change
These cars need an oil change every 5000 miles WITH SYNTHETIC
I would guess the breather is completely clogged and can cause numerous issues (and they get worse if not fixed/replaced)

[Astro14]

Breather is probably clogged, 10,000 miles is WAAAAAAAAAAAAY too long for an oil change
These cars need an oil change every 5000 miles WITH SYNTHETIC
I would guess the breather is completely clogged and can cause numerous issues (and they get worse if not fixed/replaced)

Yep.

99% chance your PCV system is clogged.

Mobil 1 is good oil, but the 10w40 high mileage isn't extended drain like the 0W40. 15,000 KM intervals are unsupportable without used oil analysis to determine the oil's acidity/Ph at that point. Even the 0W40, which is designed for extended drain, might not make it that long. Once the oil turns acidic, sludge forms, and it likes to collect in the PCV system. I've attahced some representative Used Oil Analysis from my cars below. 7,500 miles on the proper European specification oil works for me and my usage pattern.

But I have objective data to validate that. Further, there is a lot more to oil specification than mere viscosity. That is discussed in an oil rant (by me) thread. I've linked that below for your potential edification in oil specification.

Since you're the second owner, it's likely that the oil service hasn't been done correctly, or as frequently as it should have been.

Your options at this point:
1. ignore it and incur thousands of dollars in future repairs when the oil seals are blown.
2. Replace the entire PCV system (cleaning it simply doesn't work, and the parts get brittle and break with age).
3. Replace the turbo, which is a shot in the dark and expensive.

Choose 2 above, that's your most likely cause. Go with all new parts. $900 isn't a bad price as your parts cost there is crazy. It's $300 for parts up here. I've done it twice.

Then - look at a good 0W40 synthetic that you can get locally. M1 is fine, as is the Pennzoil/Shell Helix. And change it no later than 10,000 KM. Your engine has been neglected, and more frequent changes will help clean it up.

With a new PCV system (flame trap in Volvo Vernacular), it should stop using the oil (you'll find quite a bit in the turbo inlet and in the charge air pipe when the the system is replaced, that's where it's been forced under pressure). If not, then you can consider the turbo, but $2,000 buys a lot of oil...

Here's an oil discussion from a few years back:http://www.volvoxc.com/forums/showth...Oil-Rant/page5

UOA on Pennzoil 5W40 Ultra in the XC: http://www.bobistheoilguy.com/forums...mi#Post2288158
UOA on Mobil 1 0W40 in the T5: http://www.bobistheoilguy.com/forums...02#Post2281431

[shin91]

Firstly, thank you for all your kind and timely replies.

With a new PCV system (flame trap in Volvo Vernacular), it should stop using the oil (you'll find quite a bit in the turbo inlet and in the charge air pipe when the the system is replaced, that's where it's been forced under pressure). If not, then you can consider the turbo, but $2,000 buys a lot of oil...

Astro14 -
That's exactly what my independent said "just top it up with oil mate, she'll be fine."

I just had all fluids flushed (not cheap) and after reading Howard's blog, will move to 7,500 km oil change intervals.
Need to get my timing belt done so maybe I'll try to get it done together with the PCV.

Billr99 - sorry mate I'm from Australia and everything is in Litres and KM. Imperial. Thanks

[billr99]

Yeah, 1500km per quart (US or Imperial?) is not good. At 370K kms, my '02 still only uses 1 litre (and maybe a bit more when its consistently below 0C) over my synoil change interval of 10K kms. Easiest enough to check for a clogged breather by putting a piece of light paper over the oil filler when the car is running and see if the engine tries to suck it in. If it does, you are good in that respect. If it blows it out, then your breather is clogged. Might as well check that as you prepare to be raped by the dealer (sorry).

Cheers,

Bill

[Scopeman]

FWIW, my 2005 with 103,000 uses about 1/2 quart of M1 0W-40 in 3000 miles. This is with a complete breather job about a year ago. If I use 5W-30 it will burn about twice that. Runs great, and I don't know where the oil is going, maybe turbo, or perhaps rings and valve guide seals as well. I bought it a little over two years ago with 75K on it. I believe it was mostly dealer serviced by the original owner.
It seems that some of these use some oil, and some do not.
However, the OP's car is way too much, and no doubt needs a breather job.

[sanfelice]

FWIW, my 2005 with 103,000 uses about 1/2 quart of M1 0W-40 in 3000 miles. This is with a complete breather job about a year ago. If I use 5W-30 it will burn about twice that. Runs great, and I don't know where the oil is going, maybe turbo, or perhaps rings and valve guide seals as well. I bought it a little over two years ago with 75K on it. I believe it was mostly dealer serviced by the original owner.
It seems that some of these use some oil, and some do not.
However, the OP's car is way too much, and no doubt needs a breather job.

same here, did the PCV last summer and it's burning still, not sure the amount just yet, but it has been down. I'm thinking I will have to go into the oil pan and check the passage way up the middle of the block where it connects to the PCV, perhaps this is clogged from down below.

[2002V70XC]

Hi Shin91,
I recommend you to do the simple test first so you can tell whether your PCV system needs replacing. This guy on youtube has a great and simple video on how to test the PCV system.
https://www.youtube.com/watch?v=FIRoc0VxLd4
if it doesn't suck in, its about time to get it replaced.

[shin91]

Hi Shin91,
I recommend you to do the simple test first so you can tell whether your PCV system needs replacing. This guy on youtube has a great and simple video on how to test the PCV system.
https://www.youtube.com/watch?v=FIRoc0VxLd4
if it doesn't suck in, its about time to get it replaced.

Thank you very much, thats a great video!

[Antherzoll]

Here's my explanation of the PCV circuit.

LOL, that's what I call it, but I'm sure there is a more technical term for it. You tapped into the hose off the intake pipe, correct?

I'll post this pic for an explanation from an earlier post in this thread.


Starting from the top you have two fittings, one hose that goes to the intake pipe (where you normally splice in the catch can) and one pipe screw fitting for the coolant port on the block. After the large 90* in the pipe where the second set of hoses are is the connection to the stock breather box. Continuing down there is another pipe screw connection, this connects to the intake manifold with a check valve style pipe screw (rattle valve). The hose at the end attaches to the thermostat housing.

So the breather box get its vacuum from the strongest source. When idling or at cruise (not in boost), vacuum in the intake manifold will be greater then what is in the intake pipe, the system will draw its vacuum from the intake manifold (lower pipe screw fitting) causing the vapors to travel to the intake manifold. Under hard acceleration or in boost vacuum in the intake pipe will be greater then the manifold, the system will draw vacuum from the intake pipe just before the turbo causing the vapors to be drawn into the intake pipe. The rattle valve will close as there is a vacuum being drawn in it so you won't loose boost through the intake manifold fitting.

That video is informative, but for the glove test you are still only testing the idle circuit as reving your engine to 2000rpm in neutral still creates sufficient vacuum in the intake manifold. What you want to do is put it in gear and rev it with your foot on the brake, if the glove blows up then the "boost circuit" is clogged at the PTC or the pipe is blocked up.