I determined that my PO 171 and 174 trouble codes on my '09 LS3 were do to a vacuum leak. I found a water separator in front of the PCV valve (my guess is that it was installed to eliminate blow-by.) At any rate, the water separator was damaged and caused a vacuum leak. I removed it, at least temporarily, to stop the vacuum leak and smooth out the engine, which it did. The air/fuel ratio is now spot on. How necessary is the separator?
Thanks for your insight and suggestions.

 

Is the water separator stock or did someone add it as an aftermarket device?

 

Hi,
It was installed after market when the engine was tuned with a twin turbo system. I was able to locate a replacement from Norgren. In the mean time, the by pass is working fine.

 

What's it separating the water from? Water injection maybe?

Does it still have the twin turbos?

 

I'm no wrench but anything that breathes creates condensation. This separator expels the condensation prior to entering the crankcase. Yes, the turbos are intact.

 

On a normally aspirated engine, the condensation is disposed of thru the PCV and burned.

 

Perhaps the turbos cause more condensation than the crankcase can otherwise handle.

 

Could be but I'd need somebody to explain the physics to me.