Aircon causing positive PCV pressure?
 

Hey,

I recently bought a 2001 S60 B5204T5 from my dad for cheap and it understandably has some issues. Very recently, it developed a very critical oil leak after the intake cam gasket seal was blown out. This was replaced.

From what I understand the gasket might have been blown out from a mix of an old seal and the aircon working on low rpms (?).

I have done the old glove test on my oil filler cap, air con off leads to slightly negative pressure. Air con on leads to just borderline negative pressure, but the glove does not inflate. My dad says it would help if the car revved higher when the air con was on but it does not. I was wondering if my PCV is clogged or if this is something I should even be that worried about if the pressure isn't necessarily positive. I am just paranoid about any oil leaks since the cam intake gasket seal came out.

Another one!

Under the manifold, above the alternator is a banjo bolt that provides the vacuum for the PCV system.
On earlier cars, this banjo bolt simply has a restricted orifice, so under boost, the crankcase will always be pressurised to some extent. Now these cars are old, and the seals a bit less than perfect, priblems will arise.
This is most likely why your intake cam seal blew out. It happened to my wife's V70XC with the B5244T3 engine, with an absolutely clear PCV system. and yours is the third other car I have heard about. Always the intake cam seal too.
Later cars have a modified banjo bolt with a non-return valve built in to prevent the crankcase being pressurised under boost. This is a direct replacement for the original (although vida says otherwise and gives a part number for a bolt with no check valve for some reason). I would highly recommend you get the new design of bolt and replace the one you have.

Part number 31325709.
I wouldn't get a second hand one though, some of the early versions in 2005ish had an issue whereby the check valve ball got ingested by the engine!
Mine came stamped 2019 on the bolt head.

Hey, I really appreciate your reply. Just to confirm the part number you gave is of the new revised bolt. Also, do you possibly know of any resources or tips I could use for the replacement, if not some advice?

I am optimistic about this answer.

Yes that is the revised one.

When I replaced it, it was at the same time as a (completely unecessary) replacement of the whole PCV system so the manifold was off/ loosely in place and the intake pipework / ETM etc was removed so I had the best possible access.

I _think_ if you are quite deft you should be able to do it by only removing the power steering pump and alternator to give clearance to get the bolt in/out.
There is not room to do it with the alternator in situ, even with everything else off, I know that much.

Make sure you put two new copper washers on it, and be careful not to cross thread it in the Alloy manifold.

Apologies for a slightly hi-jack, but Chris1Roll, do you have any pictures of doing this?

I get positive pressure on idle (yet to try at 1500rpm+) and would like to investigate a little.

I've tried looking back through your posts, but to be honest there's far too many to go through all of them! :teeth_smile:

Not specifically of replacing the banjo bolt, but there are pictures and general ramblings regarding the PCV job which may help you on my readers cars thread in Pistonheads:
https://www.pistonheads.com/gassing/...f=47&t=2006981 around March 2023 was when I was doing it.

Brilliant thanks. Do you know if the PCVs are a problem on the petrol models only or the diesels too?
I can't quite seem to find enough information either way, and a lot of people saying that they don't exist on the D5 (I've got the Euro 3).

Solved!
 

Hey,

So I have solved my little aircon pressure problem. It was indeed the PCV banjo bolt. I have a 2001 2.0L petrol S60 and the bolt didn't even have a year marking on it, all I know is that it did not have a boost valve inside at all, it was just hollow. I replaced it with a 2020 bolt (the new one was slightly longer, which caused me a headache.)

I managed it all WITHOUT removing the alternator. I removed the top coolant hose, loosened the turbo air intake and removed the dipstick holder. Because I have slim hands, I could fit them between the alternator and intake manifold and undo the bolt (this was after I had broken it loose with a filed down 17mm so it fits in the spot). However, because the new bolt was longer, it kept being prevented by the alternator's plastic backing from going straight into the hole. I filed down this plastic backing and the rib on it, giving me enough room. I controversially reused the copper crush washers as the OEM ones I ordered were too big. If you have some time and more mechanical proficiency than I do, then I would highly recommend loosening the alternator, however, if you feel like it, you can go through with my method (a mirror on a stick is extremely useful).

Now my car (which may be a placebo) runs a lot better. It also has better negative pressure in the crankcase, compared to what it was before. If anyone has any questions please ask, keep in mind (as you have seen above) that I am no professional.