Rep Power: 0

Help!

I've got a 2003 Si Coupe (Canadian Car) 1.7l vtec with 130k km. I commute roughly 2000 km every weekend ( 1000 km each way - interstate 90% of the way)
I've got two problems I can't seem to figure out.

1.
It's pushing the coolant into the overflow bottle but not bringing it back to the rad. Car has never overheated. I add about a 1/2 litre of coolant back to the rad weekly. Run it with the cap off until no more air. Once the air is purged it doesn't bubble anymore.
2.
Oil consumption is high - adding 1 litre per 1000 km BUT only sometimes. Seems I can drive for days and not use any and then BAM need a litre. I check every morning during the week and then each fuel fill up on the commute. Most recent commute checked oil 500 km into trip - all good. Next check 500 km later needed a litre.

I don't race, no mods, gas mileage stays consistently good, RPM's haven't changed, power hasn't changed, not overheating. No coolant in oil. Nothing to indicate problems.

I've changed the timing belt and water pump. PCV valve and O2 sensors changed when engine threw codes to indicate.

Any ideas? Head gasket?

 
Rep Power: 314

Head Gasket is toast. Check for exhaust gases in the coolant system.