Just had the VF40 Turbo (OEM) replaced on my 2006 Outback XT.
I began noticing heatshield rattling and a myriad of other noises in the last month. So when I took it in to get brakes and tires I asked the shop to troubleshoot the noises. They fixed the heatshields but there was one noise they coudn’t figure out. Now they are an independant mechanic, but they’re used to dealing with trucks (I live in a rural area of Western NY), and maybe a few turbo diesels. So when I got home I listed to the car, and now that all the other noises were gone I could focus on this one.... and it was coming from the turbo.
Fortunately for me there is a great Subaru shop out here, but its about 30 minutes away. So I took it there to have them troubleshoot it. They focus on Subarus and they have a lot of experience with building performance engines for Subarus, but also drag cars. So these are the people I trust with more difficult issues.
The noise was a rattle on deceleration, coming from the turbo area. Before they took it in back, the mechanic I was talking with went through a few different scenarios, but all of them meant replacing the turbo. The car has 200k miles, but the engine was rebuilt 100k miles ago, along with a new turbo. So I was a little disappointed the turbo was already seeing issues.
As it turns out the waste gate actuator (not the solenoid) was stuck, so whenever I let off the gas, the boost couldn’t exit the waste gate like normal. Fortunately my younger brother had the same model turbo that he took out of his Legacy, when he replaced it with an STi turbo. So the shop replaced it with that one.
I guess my old turbo wasn’t building much boost at all, because now this car pulls harder than my old E60. It helps that the car is 1000 lbs lighter and only down 50 HP. So now the car is very ready for the winter weather to come. Refreshed turbo, new tires, new brakes all around. (Even had them change the coolant). It feels like a completely new car, and I love it!