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Rear main seal failure cause detected? 850

posted by  someone claiming to be Dan on  Tue Jul 20 02:01 CST 2004 [RELATED]


I have recently replaced my rear main engine seal in my 1996 Volvo 850 (non-turbo) with 80,000 miles on it. As a reader of many posts on rear main seal problems in this forum I am aware of the excessive crankase pressure problem with these cars.

I replaced the rear main seal,replaced the oil trap(oil vapor separator (under the maifold) and was told by my tech that he had cleaned out the vacuum line leading into the flame trap holder. Still,I was noticing blowby when I pulled the dipstick with the engine running.

Yesterday, I checked my flame trap and found the tech had removed it and noticed the vacuum line was detached from the flame trap holder. I removed the vacuum hose from the vacuum tree and probed the line. FOUR INCHES OF THE TOTAL SIX INCH LINE WHERE PACKCED SOLID WITH CARBONIZED OIL WITH THE CONSISTENCY OF CONCRETE. I could not probe and clear the line with rigid and pointed coat hanger wire and broke the line.

I immediately called my volvo parts supplier and asked for the the vacuum hose and rubber connecters. He said these were special order items because not many customers ordered these parts. He did volunteer to look for some "out back". Luckily, for me, he found some left over from a previous customer's order. I installed it and drove the car fast and hard. I checked the oil dipstick with the car running and NO MORE BLOWBY! The cost of hose and connecters $2. My time to disassemble and reinstall was 30 minutes.

Conclusion:
THE COST AND TIME TO CHECK THE VACUUM LINE AND INSTALL IS MINIMAL. ALWAYS DO THIS BEFORE THE MORE EXPENSIVE JOBS. I SUSPECT DUE TO THE NARROW WIDTH OF THE HOSE IT MAY CLOG REGULARLY. IT MAY SAVE YOU THE COST OF A REAR MAIN SEAL AND OIL TRAP (VERY EXPENSIVE AND EXPENSIVE IN TECH LABOR). I WONDER IF SERVICE SHOPS ARE CONCENTRATING ON THE HIGH COST REPAIRS AND NOT THE SIMPLE AND INEXPENSIVE VACUUM LINE REPLACEMENT. (MY PARTS GUY SAID THAT THE SERVICE DEPARTMENT GENERATES HIGH DEMAND FOR REAR MAIN SEALS AND OIL TRAPS, BUT LITTLE NO DEMAND FOR THE $2 CLAMPS AND HOSE I PURCHASED. IS THIS SIMPLE IGNORANCE OR PROFIT MOTIVE AT WORK?







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    Rear main seal failure cause detected? 850

    posted by  RonJon on  Tue Jul 20 18:08 CST 2004
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    Just a footnote to PCV system and oil leaks.

    I have been working professionally as a Volvo mechanic for more than 20 years and consistently see this,

    Those customers who get their oil & filter changed routinely {3months/3000 miles} never have plugged vacuum hoses, rarely need the flame trap replaced and rarely have oil leaks.

    Those who aren't so "anal" typically have those problems and oil/vapor separators are plugged or restricted.

    These are often the ones who use synthetics and then don't change the oil because they believe somehow synthetic oil doesn't get dirty.

    Also, I see K&N filters installed but then are forgotten {causing many drivability problems and part failures} or remembered too often {too much oil} with the same results.

    Volvo engineers don't build efficient, clean and powerful engines and then stick a restrictive air filter on.

    Dirty air filters are as much responsible for PCV problems as is failure to change engine oil.

    Anyhow.... 3 months or 3000 miles and follow the maintenance schedule and you will have few problems.








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      Rear main seal failure cause detected? 850

      posted by  someone claiming to be Dan on  Wed Jul 21 02:28 CST 2004 [RELATED]

      What concerns me the most is that I am anal about this vehicle and this problem has occured despite my vigilant auto care.

      I change the oil and filter every 3000 miles. I inspect clean and/or change the flame trap at this interval also. I inspect the air filter every other oil change and repalce it at 15k miles. I own and use the Haynes and Chilton 850 manuals and follow their overly cautious maintenance regimens. I have a volvo trained dealer tech who checks my work and does the big stuff I cannot do after his regular work hours.

      My conclusion is that a problem which shows up so often in posts in these forum from people who are assumed to be Volvo savvy and also shows up a shops too often must be related to a unanticipated design defect in a narrow short vacuum line which can suck up oil and solidify causing a major problem--rear mail seal failure.

      A simple service bulletin from Volvo NA to all techs suggesting a cleaning of the vacuum line when cleaning or replacing the flame trap would go a long way in soothing many consumer's ruffled feathers.








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    Rear main seal failure cause detected? 850

    posted by  someone claiming to be Dan on  Tue Jul 20 03:14 CST 2004 [RELATED]

    Additional Notes:

    For all you "clean the flame trap and change the oil" folks:

    I change oil (Castrol 10-30) and filter (Volvo oem) every 3000 miles or 3 months. I remove check and/or replace the flame trap and "O" ring at this time if necessary. The flame trap has never been plugged. I intend to check the vacuum line for blockages every time I inspect, clean or replace the flame trap in the future.

    There are some similarities here to the Volvo 240 Air Mass Meter cooking problem which many of you former 240 owners may have had. I owned two 1985 (his and hers) Volvo 240 s. Every other year one or the other would cook an Air Mass Meter. These used to cost $400 with labor and I went through 4 of them before a non-dealer tech remembered an obscure service bulletin that suggested checking to see if the air intake valve had failed in the closed postition. Sure enough mine had failed in both cars. This $27 part was replaced in both vehicles and no more cooked air mass meters occured. I wonder if to this day many more air mass meters are routinely replaced in shops while overlooking the air box intake valve?








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      Rear main seal failure cause detected? 850

      posted by  CJLomax on  Tue Jul 20 14:51 CST 2004
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      last visit: Tue Jan 18 20:40 CST 2011
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      Things that make you go hmmm .... good posts on both topics gents. Thanks for the insights. I'll be checking both now in the immediate future.

      CJlomax







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