Just bought a UK Subaru Impreza with engine mods 330BHP and noticed in the history its been run on 10/40 but is now using 5/30 fully synthetic on a rebuilt engine,

What do you guys n girls use,

 

What model and what year?
Personally if its a classic then get the 5w30 out of there, its not recommended by subaru at all, if its a new age then I still wouldnt recommend it, I would go with a 5w40 fully synthetic oil.

Tony

 

Thanks for the reply.
Its an X reg classic with a uk standard engine, version 8 crank and rods with uprated bolts and shells, bigger turbo...
Ive just checked and its currently on titan race pro s 5w 40 and was run on 10w 40 for the running in period of 500miles is this oil suitable to carry on with?

 

Well i wouldnt run a fully synth oil on a new build engine for atleast 3k miles to let it bed in properly, then go with the 5w40

Tony

 

My Castrol book at work recommends a magnatec 5/30 for my bugeye

 

Its a classic and 5w30 isnt recommended by subaru on these engines (nice page in the book with WARNING on there )
Even in a bug I wouldnt use a 5w30, and I would definately not put castrol in there

Tony

 

Millers CFS 10w40 or Titan (Silkolene) Pro-S 5w40 for me

 

Ideally go for a 5w-40, but if it's a bit rattly on start up, go for a 10w-40 instead. Pro S, Millers CFS, Redline, Motul 300V and Gulf Competition are as good as it gets.

Cheers

Tim

 

Noticed you said no to castrol. Why is that.

They have an offer in halfords.

Any ways I'm using 10w/40

 

Castrol (especially magnatec) doesnt always agree with scoobs, hence the reason not to use it, much better oils out there
Lots of old threads on it

Tony

 

Which is exactly why I use 10w40

 

New build engine done 2000 miles was using mineral oil but now im using 10w40 semi Millers oil fro another 3000 miles then fully synt oil after that.

 

Castrol Magnatec isn't recommended for any turbocharged engine to be honest. The main selling point is that this oil "clings" to surfaces meaning that when the engine is switched off, the components are left with film of oil which is supposed to offer an extra level of protection on cold starts.

The problem is this "film" builds up over time on turbocharger seals, forcing them apart and causing the turbo to pass oil.

 

It's more because the Magnatec is a fairly basic oil so will break down in an engine that is hard on the oil. The top end oils we sell cling to the metal in a more effective way than the Magnatec, but they don't have issues with turbo seals.

Cheers

Tim

 

I worked within the turbocharger industry for quite a few years, and we often had turbos in that looked to have failed, but once inspected it was found that the piston ring gaps has been forced out of spec, and the one common denominator we found was the use Magnatec once we'd gone back to the customer.

Not sure what it was about the oil specifically that caused this, but we never witnessed any problems with any other oil. We would always recommend that magnatec was not to be used.