oneofeleven

Ok, my car (Impreza Turbo MY98) got new short engine. But the oil they put in (Castrol SLX 0w/30) makes me wonder if I should change it to semisynthetic (I have Shell Helix Plus 10w/40 waiting...) I have now driven only 100 miles after engine change. Is it still ok/preferable to use semisynthetic instead of fullsynthetic (SLX)?

scoobyslut

I shudder at the thought of 0w oil in a turbo engine, its far too thin for Uk use, better change for a 10w oil, be it a 40 or 60 grade but I'd never put oil that thin in an engien running at our temperatures, not for road use.
use of either semi or fully synthetic oil is your choice, both are ok.

darkblueturbo

I don't know, so could be talking **** but I think I heard that new engines should be run on semi synthetic during the running in period then fully synthetic thereafter.

Likewise I wouldn't use 0 I usually use 10w/50 silkolene pro s

oneofeleven

It just "popped in my mind" that maybe there is some reason why the garage put such a thin oil into new engine and it would have something to do with running in (driving nice and easy so engine isn't running especially hot). Obviously not. Another thing was going to semi from fully synthetic. I guess it's ok because the engine is still almost undriven. Thanks for comments.

MorayMackenzie

I am not 100% sure that a 0 grade oil was necessary, however, it is normal to use a thin mineral oil for running in.

Running in is the final stage of engine preparation, where all the components get bedded in. If you change to fully synthetic before the engine is properly run in you will prevent this process and end up glazing the bores and getting poor ring seal.

I believe it is normal to run the engine in for an initial ~1000miles on thin oil, then change to a semi-synth for the next stage of running in.

It may be a good idea to do a search on "running in" or similar to read about the process.

oneofeleven

Yep, search can find a lot of information about running in a new car in general and I don't want to start another discussion. I just have now this "oil hassle" concerning new engine in old car and first 1000 miles. So where can I get thin mineral (or semisynthetic) oil (they all seem to be 10w/40)? Or lets put it this way: I'm sure here are many enthusiasts who have put many ;-) new engines in their cars, what kind of oils have you used?

Or maybe I'm just splitting hairs and I should drive my car. And after running it in drive it like it should be ;-)