gmctd wrote:
A Diesel turbo charger does not have seals, like in a gasser (patooie!) turbo, because a Diesel does not develop vacuum in the intake - therefore there is no seal to wear out - Diesel shaft sealing is centrifugal\slinger and labyrinthine on the compressor end as Boost pressure is greater than oil pressure in the housing bore\full-floating bearing\shaft interface - on the turbine end is same labyrinthine\centrifugal, with addition of a piston-type ring in a ring-groove on the shaft, mainly to prevent hot exhaust gasses from entering the bearing area - thus, a Diesel turbo will also spool up quicker than the similar gasser (you know!) version - the main faliure resulting in oil leakage is bearing\shaft deterioration, usually from extended oil changes, sometimes from 'coking' - Diesel-rated oils are resistant to coking, where normal passenger car oils are not - soccer moms'n'dads are more likely to put Wally-world Equate oil in a Diesel, creating more incidence of failure - plus, if you've just reached the top of a 45* grade towing a trailer, immediately stopped and shut the engine down, you're likely to encourage intense coking in the bearing housing even with Diesel-rated oil, resulting in excessive oil leakage - one reason I like a mechanical EGT guage, direct TC connect: indicates cast-iron temperature long after the IGN is off
FYI: since the turbo is officially accepted as an exhaust muffler in most states, the term 'worn out muffler bearings' is no longer a laffing matter....................
GM: I have not been able to get any data on whether our Garret M53 turbo is the ball bearing type like most of their small displacement units have, Or if it has the journal type bearings like the big boys. Do you have any input?