I am using my new silvia with the ese pod adapter with illy pods. When I press the coffee dispense button with a pod in place, coffee begins to come out of the right orifice, then after a few seconds it begins to leak noisily from what appears to be the contact between the grouphead and portafilter.

"leaks noisily from what appears to be the contact between the grouphead and portafilter"
* Leaks from top of portafilter and group head are caused by poor sealing at head gasket.
* wipe top lip of portafilter before inserting into group.
* check if group is clear of coffee grounds, paper bits, tissue, dry crud. Use a head cleaning brush (tooth brush works) and wipe group clean (do not use screwdriver to scrape!)
* Make sure when inserting portafilter it is seated properly. (check your manual for procedure) Note the position of the portafilter handle if it's in the right position AFTER you tighten it. Is it far to the left? or stuck and barely hangs on to group?
* Barely hanging on to group? Check if pod is too big. Note; you can't double shot or use 2 pods in a single pod basket! Make two separate shots for a double.
* Handle tightens but slips off group or still leaks when pulling shot? Worn out or missing gasket. Gaskets are made of rubber and can crack, drop out, or pit. You will need to have the gasket replaced. Check with vendor or MFR for service/parts.
* Make sure you have the correct portafilter. Many look the same and may even fit but when making fine adjustments or critical shots they don't work right. Check manual or vendor for confirmation.
* Make sure you have the correct basket. The portafilters may have different baskets or cups that can be inserted. Many have special uses that can affect the pull of a shot. Fewer holes causes slower flow and longer brew time. Many holes gives a weaker shot but smoother less bitter taste. There is a blank basket that has no holes which is used for backflushing and cleaning of the group. Check your manual or vendor for which basket you should be using. Odds are that you have a standard basket ment for ground coffee and not pods. (you can remove the coffee from the pod but it will be messy.) Ask for the optional 'POD' basket insert.
* Finally if everything checks out and your still having leaks then your machine needs service as the group head or valve needs replacement. Call your vendor or MFR direct.
Aloha! ukeboy57 (youtube)

P.S. Looking back at my service with pod conversions, I've found that most if not all pro-machines don't really like the pod adapters. Sure it will work but shots are weak and poor. Pods really like a very tight fit with a very small portafilter basket(chamber) I mean like the size of a soup spoon! They like very slow and very hot water pumped with a vibration type pump to extract all the essence from the paper filtered coffee. Illy is an excellent coffee pod with a very rich aroma and good creme. The best for them (pods) are the dedicated pod machines (won't do ground coffee, only pods). If you must use a pro semi-automatic machine then I would suggest adding a port constrictor to the portafilter output. There may be a third party supplier that has a compatible adapter for your brand. I've come across some of these very extreme tools for the elites coffee affectionato. It restricts the flow at the output thus causing the hot water to brew longer and at a higher pressure to force the hot water and steam into each coffee grain. (think pressure cooker) Some of the better ones are adjustable. But note that these will need daily or cleaning after each use as these restrictors have very tiny holes which clog unless flushed after each use. Good luck 9on your pursuit of the perfect cup!)