Don’t be that person that just installs a new turbo without diagnosing what may have caused the old turbo to leak oil or disintegrate!
Sometimes people blow up one or more otherwise perfect replacement turbos because of oil supply or drain issues!
I’d do some basic health checks eg:
Perform an inlet pressure test using smoke or soapy water spray.
Logging and learning view: fuel corrections reveal inlet tract leaks.
Check boost control hoses etc before eg removing dump or turbo inlet pipe to check for runout/damage on the compressor wheel or exhaust turbine.
These checks need to be performed as an overspeeding turbo can break apart due to too much rotational inertia.
Overspeed can be caused by a failed boost control solenoid, boost control solenoid hoses routed the wrong way, or due to boost leaks!
Excessive blow-by: combustion gasses leaking past the piston rings can be diagnosed by attaching a boost gauge to a hose fitting installed in a spare oil cap.
The crank case should be under vacuum if the engine is running, if it goes positive pressure over 3000rpm on load, suspect compromised engine compression.
Remove intercooler or charge pipe to check for shavings in the compressor outlet. Its unlikely that shavings from the compressor wheel or housing will make it past the intercooler, but checking the cold side piping and throttle-body for shavings is a good idea regardless.
Check, clean and or replace the PCV whilst the intercooler is removed.
The valve should be clean and rattle when shaken.
If in doubt, replace it as they’re very affordable.
Excessive crank case pressure can force oil out of the chra into either the dump, turbo inlet or compressor outlet.
Maybe grab a new core for your turbo from kinugawa etc if it is blown, but confirm if the turbo oil supply and drain aren’t blocked.
The oem hard turbo oil supply lines can crimp or crack, so carefully inspect its integrity.
Oil starvation will kill the new turbo in seconds.
Check if your car has turbo oil feed banjo bolt filters and remove them if they’re blocked with soot or swarf.
The turbo oil feed banjo bolt is on the rear of the rhs head on prefl, or on postfl top of the rhs block under the turbo inlet.
Banjo bolts that have filters for the turbo (and avcs system) are known to have a raised section on the bolt head aka a nipple.
A sharp tooth pick is useful for fishing for and pulling out the oil filters.
If the filter is broken up, try blowing compressed air past the hole to draw it out, or put a rag over the hole and have someone crank the engine over in a short burst (pull fuel pump fuse) to let oil push the filter out.
Some turbo vendors recommend capping the turbo oil feed (leaving the rhs avcs feed intact), and running a new oil line to feed the turbo, via a serviceable filter, from a sandwich plate above the oil filter.
In the case of engines with very high oil pressure, as stock or modified (including H6) a Turbosmart oil pressure regulator is recommended in particular for ball bearing turbos.
The OPR will require an oil drain to be fitted, common locations are tapping a port into the rhs rocker cover (h6), welding a bung into the sump or dipstick tube, or a port tapped into the oil cap. For journal bearing turbos, the stock, as supplied, restrictor should work but may require changing in the case of very high oil pressure.
Ensuring the turbo oil drain is very important, any restriction here will cause the chra to leak.
Its accepted that the stock oil drain hose and fittings are of the perfect size if working properly.
If using aftermarket AN fittings and hose, the inner diameter of the fittings must match or exceed the oem items. For this reason, sticking to oem is regarded as the best solution.
Also re-crimp the end tanks on the stock tmic, the tabs are notorious for opening up causing leaks.
I use a set of parallel pliers to recrimp the tabs.
This is all a great opportunity to upgrade various items, eg for stock location top mount intercoolers, install an AVO or Kobe throttle-body hose with good quality screw clamps eg oetiker, norma, or murray.
A silicone turbo inlet hose is also a good idea, as is getting your new setup tuned.
If the car is over 200k km, I’d consider replacing any tired pcv hoses, upper & lower inlet manifold gaskets, injector and cam sensor orings and the coolant crossover pipe orings. All this is easier to do in one go when the inlet manifold is off.
Then the car will be ready for the next 200k km
