Team owner Frank Williams has accused engine partner BMW of poisoning their relationship by incessant sniping.
Williams is not happy about BMW's criticism of his team
"Our partnerships in the past with Renault and Honda have been more successful and co-operative," Williams told Autosport magazine.
"You never had this constant finger-pointing. We do not constantly ask why BMW had some 150 engine failures in 2000 alone."
BMW has criticised the performance of Williams' cars in recent years.
The German manufacturer has a contract with Williams until 2009, but is expected to expand its Formula One programme next season by supplying Swiss team Sauber as well.
Williams won the constructors' championship with Honda in 1986 and '87, when they also won the drivers' title with Nelson Piquet.
And the team won four drivers' titles and five constructors' titles between 1992 and '97 while partnering Renault.
But their best results in the constructors' championship with BMW, during a period dominated by Ferrari, have been second place in 2002 and fourth in 2004 .
And despite Ferrari's problems in 2005, Williams have again got off to a slow start this season, with Renault and McLaren dominating the year so far.