Oil in Throttle Body Assembly on '04 XC70

[m4sherman]

Hi all--

Longtime reader, first time poster. I've owned an 04 XC70 for a couple of years now, and put it through a lot of long trips, often alternating between low, hot desert (SW US) and high, cold mountains (Rocky Mountains). I'm told it was very well taken care of at the dealership by a single previous owner before I bought it, and I have kept up with frequent Mobil 1 oil changes and attendance to a few minor issues over the last couple years.

On a recent 200+ mile trip, the Check Engine light came on. I was able to run the code as P2177 (System Too Lean Off Idle). Car still ran fine and I was able to get to destination with no issues. I visually checked what I could in the engine (looking for obvious cracked/failed hoses, etc) and everything checked out. I cleared the codes, and nothing came back after some light driving around town. About a day later, however, Check Engine came back on, this time accompanied by the dreaded "Reduced Engine Performance" message and the car going into limp mode, limiting me to about 5-10 MPH. When I got it home, a new code: P2108 (Throttle Activator Control Module Performance).

Quick searching brought up a lot of information and a clear path forward--clean or replace the Throttle Body. Mine is the Bosch job, and because this happened away from home and over the holidays, I opted to grab a new part locally (and was lucky to be able to get it that day). I swapped that out, and car has been running fine since.

However, when I inspected the old Throttle Body, I expected to see a part worn down with age, likely broken gears, etc. In my case, though, the part looked fine, but the assembly had a good bit of oil in it (presumably fouling up the electrical contacts inside that assembly?):

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Furthermore, there was a decent bit of oil and what I assume was condensate pooled in the throttle inlet tube, where it connects up to the bottom of the Throttle Body:

55E49B6A-E60F-4E00-8594-59B5E2D25287_1_105_c.jpeg (85.44 KiB) Viewed 521 times

This made me think that some PCV issues were the culprit, but on doing the "glove test" at the oil filler cap and the dipstick tube, I get negative pressure or very slight positive pressure (no ballooning gloves). I assumed I'd see a ton of excess positive pressure, explaining the generally oiliness around and below the Throttle Body, but that doesn't look like the case.

The Throttle Body is not a cheap part, and it's not exactly a fun job, so my question is: did I just get supremely unlucky with oil managing to get into the Throttle Body assembly, or is there something bigger going on that could ruin the new Throttle Body in the same way? PCV issues still seem to fit the larger picture, so is there perhaps a better/different diagnostic I should be doing instead?

[jonesg]

the intercooler might have condensed oil in it. I've read where someone drained it, not sure how, maybe draw it out with a small tube.
The charge air pipe often has oil at the turbo end, it makes sense that it will migrate down stream.
The whole system strikes me as a messy design.

[scot850]

The Volvo intercooler on the older V70's (pre-00) were prone to building up condensate especially as they get older. You will get bypass oil from the turbo as it wears and some from the PCV system. I have had x2 P80 chassis Volvos with turbos and had both of the car's intercoolers flushed. The older Volvos if they have the original intercooler, had a 1/4" hole drilled in the lowest point to allow condensate to drain out. When the weather is really cold the intercooler will generate a bit when the engine is turned off and there is no air flow through it. Not sure if the P2 cars have the same feature.

Neil.

[sal329]

When I did the glove test on mine the glove ever so slightly had some movement but when I took the PCV off it was so clogged