geordi wrote:
About the oil... Any xW-40 oil becomes the same 40 weight after the temperature rises above the cut-off point. IIRC, that is something like 0 degrees F. So the winter weight doesn't matter as such to the thickness. Once the engine is running, the oil warms up and is a 40 weight.
The play in the shaft side to side is the big concern, and the thickness of the oil is as well. The passages in the turbo around the bearing are amazingly small, about the thickness of a pin. The oil cushion around the center shaft is about half that thickness. Your oil change interval and the cleanliness of your oil is VERY important for this turbo. I wouldn't push the change interval past 6k, and ALWAYS use the best synthetic oil you can find, diesel rated.
As for the cost of a turbo, rebuilt turbos are not available from Garrett. If you talk to your local Bosch Injector service shop, they might already be a Garrett distributor or can direct you to one. My local South Florida ADS (Association of Diesel Service) / Bosch shop found me a brand-new turbo from Brazil for $1080 a few months ago. That was without any core charge.
Garrett does not offer parts either, but if you want to replace the main journal bearing, have a search for my thread called "turbo rebuilding might just be possible" and you will find my write up and a link to the parts kit that I used. $70-odd dollars seems a decent gamble if you want to try rebuilding it yourself, it isn't that difficult and all it requires is basic tools. I don't know if I mentioned in the writeup, but the compressor wheel is reverse-threaded. Hold it with a towel when you unlock it (righty-loosey) and you won't cause it any damage.
Lets see, they make 0W-40 by adding Viscosity Index Improver to 0W oil.
If the Viscosity Index Improver breaks down what do you end up with, you got it 0W oil.
Run 0W oil with broken down Viscosity Index Improver, you are running 0w oil through the turbo and the rest of the engine, not 0W-40. If you use 5W-40, and the Viscosity Index Improver breaks
down, you have a better safety margin. If you don't live in -40C/F weather, what the #ell do you need 0W-40 oil for?
I have run turbos for well over 250,000 miles with out problems, i think it is more than just luck.