2 replies to this topic

[st0neyHDII]

i recently changed out my old turbo cuz it was leaking oil, the shop i took it to had a used turbo sitting around so i swapped it out and put the used one in. they threw it on the dyno and i noticed a large amount of smoke coming from the exhaust which never happened with the first turbo. the smoke is a bluish color so im thinking its something to do with the oil burning.

im thinking its either a bad turbo or the valve seals on my head have gone bad.

any advice?

[Raley]

Oil or water cooled turbo? What turbo?

[Gtjetta97]

If running super rich it is most likely fuel. If new pistons not past 1500 miles then the rings need broken in to seal or someone did not break them in properly and they are glazed. When breaking in new rings you keep under 60 mph for 1500 miles to keep massive heat away from the walls to prevent glazing, they will never properly seat that way. If it is compressor intake side leaking oil check intake pipes. If it is intake valve leaking it will show at idle as massive cloud of smoke when you rev it. If it is exhaust valves only the plugs will be dry and a shop used too big of seals on it. They might rise up due to the hot exhaust valve expanding and pulling the seal off while the intake valves might not be leaking do to being colder and not pulling the seals off. This would lead you to assume leaking turbo exhaust side if your plugs are dry. I made this mistake!!! If its leaking under boost it is not your turbine side because backpressure is pushing exhaust gas into the turbo bearing housing along with boost from the other side. If your PVC is not set up correctly then it could be pressurizing the entire system and then you will blow all your oil seals out. Even if the turbo is used it should not burn oil under boost because air enters both sides of the turbo under proper circumstances and exits usually to atmosphere in the drain line via intake air filter on some stock setups. This is one reason turbos have a whistle sound. That is boost blowing from compressor side behind the compressor wheel into the bearing housing to keep the oil in. Try to boost leak test a turbo and the whistle stops if you plug the oil entry/ exit. This is how it works. Don't guess it's the turbo like I once did if it's the exhaust valve seals. And check them all not just one. Good luck