City moved ahead on 16 minutes when Aguero beat the offside trip from a Fernandinho through ball before knocking his shot beyond the helpless home goalkeeper Jussi Jaaskelainen.
The visitors were always on top and added a second early in the second half when Aguero's header from a Silva free-kick somehow managed to elude Jaaskelainen, who should have kept it out.
An inventive Ricardo Vaz Te overhead kick from close range somehow gave an out-passed and out-thought West Ham fresh hope just before the hour mark, but City finished matters off with their best move of the match 10 minutes from time.
Yaya Toure slid the ball into the path of Aguero, whose backheel enabled Silva to send a spinning shot into the corner of the net to finally bury West Ham. Ominously, title favourites City move up to fourth place in the standings only three points behind leaders Arsenal, who routed Norwich 4-1 earlier in the afternoon.
16' - AGUERO OPENER: Aguero beats the offside trap before beating Jaaskelainen with the finish. Lovely ball from Fernandinho. West Ham punished for going to sleep.
22' - AGUERO BIDS FOR A SECOND: Aguero drives at the West Ham defence. Jaaskelainen dives to make the stop, but Silva just fails to tap home the rebound. West Ham being put through their paces at the moment.
51' - AGUERO FINALLY MAKES IT TWO: Aguero with the header eight yards out from the Silva free-kick. Jaaskelainen with weak hands. Should have made the save. City now lead 2-0.
58' - WEST HAM LIFELINE: Vaz Te with the overhead kick from Stewart Downing's flick on and West Ham back to 2-1 behind. Diame offside earlier on in that move, but flag stays down. West Ham back in this game.
61' - NEGREDO RATTLES BAR: Negredo dashes onto the Aguero pass, but so unlucky to see the ball come back off the underside of the bar with Jaaskelainen well beaten for pace.
67' - ALMOST THE TREBLE: Another brilliant effort by Aguero going for his treble, but Jaaskelainen dives to push the ball wide of his post
80' - SILVA SEALS IT: Aguero with a backheel into the path of Silva, who strokes the ball into the corner of the net. Sublime goal from City. A 3-1 lead.
This was Man City’s biggest Premier League away win of 2013 – and biggest since they won 3-1 at Newcastle on December 15th 2012.
West Ham have lost their last three home matches in the Premier League, after only losing four at home in the whole of last season. It is their worst losing Premier League home run since March 2010.
Manuel Pellegrini has won his first league away match in nine as manager of Man City and Malaga, stretching back to April 2013 (seven defeats, one draw).
Manchester City recorded their first Premier League away win of the season at the fourth attempt.
This was only Silva’s second Premier League goal outside of the North West (of a total of 16) – 10 have come at home, whilst his first four away from home came at Blackpool, Man Utd (twice) and Bolton.
TALKING POINT: Are City's away day blues in the Premier League over? It's a bit too early to suggest they are the finished article in Europe, but they will be hard to handle in the Premier League if they can maintain this level of performance. After losing at Cardiff and Aston Villa, this was much more like it from Manuel Pellegrini's men.
MAN OF THE MATCH
Sergio Aguero (Manchester City): Marvellous performance from the little Argentina forward. West Ham struggled to handle his pace and movement.
West Ham United: Jaaskelainen 6, Demel 6, Rat 6, Tomkins 5, Reid 5, Noble 6, Morrison 5, Diame 6, Vaz Te 6, Downing 5, Nolan 6. Subs: Jarvis 6, O'Brien 6, Petric 6.
Manchester City: Hart 7, Richards 7, Garcia 7, Nastasic 7, Clichy 7, Nasri 7, Fernandinho 7, Toure 8, Silva 8, Aguero 9, Negredo 7. Subs: Kolarov 6, Milner 6, Jovetic 6.
THE MATCH IN A TWEET