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Yeah, try this Posted by Cmyles [Email]  (#1126) [Profile/Gallery]
(more from Cmyles) on Thu, 29 Sep 2011 09:25:45
In Reply to: Very interesting..., Darcey, Thu, 29 Sep 2011 08:21:45 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Darcy,
No, the comp. test won't tell you anything about valve stem seals. Such a test determines the condition of the rings and the valves only. By doing the "dry" comp. test (first) you find whether the compression is low and then the "wet" test, with a small amount of oil poured into the cylinder, tells you whether the low compression (if that's the case) is due to bad rings or bad valves/seats. The oil temporarily improves the ring to bore seal so if the reading shoots up then you have bad rings but if the reading remains the same then it's the valves that are failing to seal when closed. Usually we suspect worn valve guides or valve seals when a car burns oil after being parked for a length of time but otherwise does not. The idea being that while the car is parked the oil in the head slowly leaks past the worn seals and/or worn guides and accumulates where it will be burned on start-up. when the car is started that accumulated oil burns off in a huge but temporary cloud of blue tailpipe smoke which eventually subsides as the leakage is too slight to cause much noticeable smoke while driving. You should definitely do a comp. test in any event.
A whining turbo is almost certainly passing oil into the induction system which would account for the tailpipe smoke.
If we really want to see whether the turbo is responsible for the dipstick smoke then try this; Connect the air mass meter directly to the throttle body and run the car. You can do that by using the rubber boot that's on the output end of the air mass meter to connect it to the "L" shaped pipe that's the first one off of the throttle body (flop it over). That will totally cut the turbo out of the system so that it can't pass any oil to the induction system. See how that effects the tailpipe and dipstick tube smoking condition.
posted by 198.233....
, Thu, 29 Sep 2011 08:05:55, Thu, 29 Sep 2011 09:25:45 <-- Viewing This Message, Fri, 30 Sep 2011 08:19:46
, Sat, 1 Oct 2011 08:56:34
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