Using thick oil will mask the underlying problem, but it's not a fix. You are causing more harm to the VVT system when using 5W-50 where 0W-20 is required. The oil will not flow properly and the components which are working fine will go bad in addition to what's already bad.
In such cases there are two options.
1) Keep using thick oil and swap the engine when it completely fails.
2) Save the engine by rebuilding it now.