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S80 '98-'06 / S60 '00-'09 / V70 & XC70 '00-'07 General Forum for the P2-platform S60 / V70 / XC70 / S80 models |
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Aircon causing positive PCV pressure?Views : 475 Replies : 7Users Viewing This Thread : |
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Mar 27th, 2024, 20:16 | #1 |
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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. |
Mar 27th, 2024, 22:25 | #2 |
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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. |
Mar 27th, 2024, 22:48 | #3 |
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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. |
Mar 27th, 2024, 23:07 | #4 |
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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. |
Apr 2nd, 2024, 18:40 | #5 | |
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Quote:
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!
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Apr 2nd, 2024, 23:44 | #6 |
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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. |
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