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crankcase pressure doom and gloom--when is the patient terminal? 850

posted by  Paul_McBride on  Fri Mar 13 10:18 CST 2009
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last visit: Wed Apr 14 09:33 CST 2010
[RELATED]

Well i had the rms replaced on my 850 w/ 160K on it. The guys doing it claim that the crankcase pressure is not due to the pcv system but rather to a worn-out engine / piston blow-by and that no amount of tinkering would reduce the pressure to an appropriate level. I have always been attentive to the car in terms of oil changes, the right filters, etc., so i am a little suspicious and will probably take it somewhere else where they are willing to do a full pcv system overhall (breather replacement). Is there a level on a compression test that would indicate a "beyond-help" level, or can a fair amount of blow-by be captured by the pcv system? I would hate to give up on this otherwise spotless car...

Thanks!

Paul








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    crankcase pressure doom and gloom--when is the patient terminal? 850

    posted by  Paul_McBride on  Wed Mar 18 10:30 CST 2009
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    last visit: Wed Apr 14 09:33 CST 2010
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    Thanks folks for the good feedback.

    I am picking up the car today which will now have a new PCV system (breather box and pipes/hoses). I have asked the mechanic to save the old box and pipes for my inspection, as this has been an issue of curiosity for me for some time now (will post images soon). The true test will be looking at the dipstick holder for smoke, the hallmark of positive crankcase pressure, and watching that new RMS for leakage.

    Overall, I will have spent $750 for the RMS and about $500-600 for diagnosing and replacing the PCV system (seems like I underpaid slightly for the RMS and overpaid for the PCV business). While I was at it, I had the left CV boot replaced (easy during RMS repair) and finally got around to the driver's seat-back cable, which also needed a new control module (used = $150). Sometimes I wish the Fed would step in and buy this toxic asset from me, lol. Autorx may be my next step per Klaus' advice.









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    crankcase pressure doom and gloom--when is the patient terminal? 850

    posted by  someone claiming to be fixit2002 on  Wed Mar 18 02:35 CST 2009 [RELATED]

    What is sometimes missed is the PCV hose connection to the flame trap. The hose is OK but the plastic tube it connects to gets blocked with a hard carbon like substance. It needs to be carefully drilled out and cleared.








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    crankcase pressure doom and gloom--when is the patient terminal? 850

    posted by  KlausC on  Fri Mar 13 14:12 CST 2009
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    last visit: Fri Oct 24 10:15 CST 2014
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    Probably compression in the 120lbs range on all 5 cyl., with a hot engine. The real test will follow the initial test, by adding a tablespoon of engine oil into each cylinder and waiting a few minutes. The oil treatment will coat the rings, and if the rings or cylinder walls are worn, the compression will increase dramatically.

    Very few 5 cyl engines, or any other volvo engines for that matter, have worn cylinders or rings. The valves usually go out first.

    If no one wants to replace the oil separator box, then get a can/bottle of AutoRx and pour it into the crancase. Follow the directions and make sure you drive the engine unitl the oil gets nice and hot every time.
    This AutoRx will remove sludge and help the breather system also. It is not a cureall, but it helps.
    --
    My name is Klaus and I am a Volvoholic.








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      crankcase pressure doom and gloom--when is the patient terminal? 850

      posted by  RTBimmer on  Wed Mar 18 04:00 CST 2009
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      last visit: Mon Jun 30 09:41 CST 2014
      [RELATED]

      Speaking of Cylinder walls, is the Block of a 5 cyl cast aluminum and are the Cylinder walls sleeved with anything?








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        crankcase pressure doom and gloom--when is the patient terminal? 850

        posted by  KlausC on  Wed Mar 18 04:34 CST 2009
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        last visit: Fri Oct 24 10:15 CST 2014
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        The "white" blocks are all cast aluminum with hardened sleeves. The old Vega had an aluminum block and no sleeves, after 40K miles, the block was gone but the rings were still good :)

        After hearing and seeing numerous blocks with heads removed, the aluminum blocks and rings still looked new after 200K miles. The valve seats are a different story.
        --
        My name is Klaus and I am a V ♂ lv ♂ holic.








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      crankcase pressure doom and gloom--when is the patient terminal? 850

      posted by  Champ 6 on  Fri Mar 13 16:34 CST 2009
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      last visit: Sat Sep 18 10:02 CST 2010
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      Yeah, so far, 1400 miles into Auto-Rx, my oil consumption, which was really bad, has improved, and while my engine did not look sludgy, it is really clean now. Maybe it CAN clean the oil seperator, but that'd be a miricle.







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    crankcase pressure doom and gloom--when is the patient terminal? 850

    posted by  Champ 6 on  Fri Mar 13 11:07 CST 2009
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    last visit: Sat Sep 18 10:02 CST 2010
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    You need a leak-down test, to see how much blow-by is occurring before deciding whether the engine is tired or not. Get your new mechanic to do that first.








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      crankcase pressure doom and gloom--when is the patient terminal? 850

      posted by  Paul_McBride on  Fri Mar 13 11:23 CST 2009
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      last visit: Wed Apr 14 09:33 CST 2010
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      Got it. Leak-down test scheduled with a new shop. I've had a very difficult time getting mechanics (incl. Volvo guys) to R&R the pcv system despite all I've read on these boards. The shop that just replaced the RMS says they never see 850 pcvs clog, which has me suspicious.








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        crankcase pressure doom and gloom--when is the patient terminal? 850

        posted by  Champ 6 on  Fri Mar 13 16:32 CST 2009
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        last visit: Sat Sep 18 10:02 CST 2010
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        I've only experience with one 850, mine, but at about 95,000 miles, mine was plugged tight. I agree, get teh pcv system R&R'd








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          crankcase pressure doom and gloom--when is the patient terminal? 850

          posted by  Paul_McBride on  Mon Mar 16 10:38 CST 2009
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          last visit: Wed Apr 14 09:33 CST 2010
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          Well I took my car in to another shop and had a leak-down test performed. Here are the results:

          #1: 8%
          #2: 20%
          #3: 24%
          #4: 18%
          #5: 18%

          These results are not too bad for a car w/ 160K--the first shop (an independent Volvo mechanic in Chico, CA) had said that my #4 and #5 were 89% and 65%, which had me freaked. Their claim was that this pressure was too high for any PCV system to bear; therefore they were not willing to guarantee the RMS they had just replaced. This seemed like a way to opt out of standing behind the job. And the car recently passed smog with no problems, so I was confused as to how I'd get these high values.

          I am having the new guy (a Euro/Porsche mechanic) replace the whole PCV system + new intake manifold gasket. When all is said and done, I'll have a new RMS and PCV system and hopefully no more headaches...

          Paul







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