diff --git a/CMakeLists_files.cmake b/CMakeLists_files.cmake
index 0c510e1a4..0675e1aa7 100644
--- a/CMakeLists_files.cmake
+++ b/CMakeLists_files.cmake
@@ -28,7 +28,10 @@ list (APPEND MAIN_SOURCE_FILES
   opm/simulators/timestepping/SimulatorReport.cpp
   opm/simulators/flow/MissingFeatures.cpp
   opm/simulators/linalg/ExtractParallelGridInformationToISTL.cpp
-  opm/simulators/linalg/FlexibleSolver.cpp
+  opm/simulators/linalg/FlexibleSolver1.cpp
+  opm/simulators/linalg/FlexibleSolver2.cpp
+  opm/simulators/linalg/FlexibleSolver3.cpp
+  opm/simulators/linalg/FlexibleSolver4.cpp
   opm/simulators/timestepping/TimeStepControl.cpp
   opm/simulators/timestepping/AdaptiveSimulatorTimer.cpp
   opm/simulators/timestepping/SimulatorTimer.cpp
diff --git a/opm/simulators/linalg/FlexibleSolver.hpp b/opm/simulators/linalg/FlexibleSolver.hpp
index d3fa0584e..d4fec9c15 100644
--- a/opm/simulators/linalg/FlexibleSolver.hpp
+++ b/opm/simulators/linalg/FlexibleSolver.hpp
@@ -21,7 +21,7 @@
 #ifndef OPM_FLEXIBLE_SOLVER_HEADER_INCLUDED
 #define OPM_FLEXIBLE_SOLVER_HEADER_INCLUDED
 
-#include <opm/simulators/linalg/PreconditionerFactory.hpp>
+#include <opm/simulators/linalg/PreconditionerWithUpdate.hpp>
 
 #include <dune/common/fmatrix.hh>
 #include <dune/istl/bcrsmatrix.hh>
diff --git a/opm/simulators/linalg/FlexibleSolver1.cpp b/opm/simulators/linalg/FlexibleSolver1.cpp
new file mode 100644
index 000000000..440d412ea
--- /dev/null
+++ b/opm/simulators/linalg/FlexibleSolver1.cpp
@@ -0,0 +1,54 @@
+/*
+  Copyright 2019, 2020 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#include <opm/simulators/linalg/FlexibleSolver_impl.hpp>
+#include <opm/simulators/linalg/matrixblock.hh>
+
+#include <dune/common/fmatrix.hh>
+#include <dune/istl/bcrsmatrix.hh>
+#include <dune/istl/solvers.hh>
+#include <dune/istl/umfpack.hh>
+#include <dune/istl/owneroverlapcopy.hh>
+#include <dune/istl/paamg/pinfo.hh>
+
+// Explicit instantiations of FlexibleSolver
+
+template <int N>
+using BV = Dune::BlockVector<Dune::FieldVector<double, N>>;
+template <int N>
+using BM = Dune::BCRSMatrix<Dune::FieldMatrix<double, N, N>>;
+template <int N>
+using OBM = Dune::BCRSMatrix<Opm::MatrixBlock<double, N, N>>;
+
+// Variants using Dune::FieldMatrix blocks.
+template class Dune::FlexibleSolver<BM<1>, BV<1>>;
+
+// Variants using Opm::MatrixBlock blocks.
+template class Dune::FlexibleSolver<OBM<1>, BV<1>>;
+
+
+using Comm = Dune::OwnerOverlapCopyCommunication<int, int>;
+
+template Dune::FlexibleSolver<OBM<1>, BV<1>>::FlexibleSolver(const MatrixType& matrix,
+                                                             const Comm& comm,
+                                                             const boost::property_tree::ptree& prm,
+                                                             const std::function<BV<1>()>& weightsCalculator);
+
diff --git a/opm/simulators/linalg/FlexibleSolver2.cpp b/opm/simulators/linalg/FlexibleSolver2.cpp
new file mode 100644
index 000000000..837b1fab9
--- /dev/null
+++ b/opm/simulators/linalg/FlexibleSolver2.cpp
@@ -0,0 +1,54 @@
+/*
+  Copyright 2019, 2020 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#include <opm/simulators/linalg/FlexibleSolver_impl.hpp>
+#include <opm/simulators/linalg/matrixblock.hh>
+
+#include <dune/common/fmatrix.hh>
+#include <dune/istl/bcrsmatrix.hh>
+#include <dune/istl/solvers.hh>
+#include <dune/istl/umfpack.hh>
+#include <dune/istl/owneroverlapcopy.hh>
+#include <dune/istl/paamg/pinfo.hh>
+
+// Explicit instantiations of FlexibleSolver
+
+template <int N>
+using BV = Dune::BlockVector<Dune::FieldVector<double, N>>;
+template <int N>
+using BM = Dune::BCRSMatrix<Dune::FieldMatrix<double, N, N>>;
+template <int N>
+using OBM = Dune::BCRSMatrix<Opm::MatrixBlock<double, N, N>>;
+
+// Variants using Dune::FieldMatrix blocks.
+template class Dune::FlexibleSolver<BM<2>, BV<2>>;
+
+// Variants using Opm::MatrixBlock blocks.
+template class Dune::FlexibleSolver<OBM<2>, BV<2>>;
+
+
+using Comm = Dune::OwnerOverlapCopyCommunication<int, int>;
+
+template Dune::FlexibleSolver<OBM<2>, BV<2>>::FlexibleSolver(const MatrixType& matrix,
+                                                             const Comm& comm,
+                                                             const boost::property_tree::ptree& prm,
+                                                             const std::function<BV<2>()>& weightsCalculator);
+
diff --git a/opm/simulators/linalg/FlexibleSolver3.cpp b/opm/simulators/linalg/FlexibleSolver3.cpp
new file mode 100644
index 000000000..68890230d
--- /dev/null
+++ b/opm/simulators/linalg/FlexibleSolver3.cpp
@@ -0,0 +1,54 @@
+/*
+  Copyright 2019, 2020 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#include <opm/simulators/linalg/FlexibleSolver_impl.hpp>
+#include <opm/simulators/linalg/matrixblock.hh>
+
+#include <dune/common/fmatrix.hh>
+#include <dune/istl/bcrsmatrix.hh>
+#include <dune/istl/solvers.hh>
+#include <dune/istl/umfpack.hh>
+#include <dune/istl/owneroverlapcopy.hh>
+#include <dune/istl/paamg/pinfo.hh>
+
+// Explicit instantiations of FlexibleSolver
+
+template <int N>
+using BV = Dune::BlockVector<Dune::FieldVector<double, N>>;
+template <int N>
+using BM = Dune::BCRSMatrix<Dune::FieldMatrix<double, N, N>>;
+template <int N>
+using OBM = Dune::BCRSMatrix<Opm::MatrixBlock<double, N, N>>;
+
+// Variants using Dune::FieldMatrix blocks.
+template class Dune::FlexibleSolver<BM<3>, BV<3>>;
+
+// Variants using Opm::MatrixBlock blocks.
+template class Dune::FlexibleSolver<OBM<3>, BV<3>>;
+
+
+using Comm = Dune::OwnerOverlapCopyCommunication<int, int>;
+
+template Dune::FlexibleSolver<OBM<3>, BV<3>>::FlexibleSolver(const MatrixType& matrix,
+                                                             const Comm& comm,
+                                                             const boost::property_tree::ptree& prm,
+                                                             const std::function<BV<3>()>& weightsCalculator);
+
diff --git a/opm/simulators/linalg/FlexibleSolver4.cpp b/opm/simulators/linalg/FlexibleSolver4.cpp
new file mode 100644
index 000000000..d2a4b2d03
--- /dev/null
+++ b/opm/simulators/linalg/FlexibleSolver4.cpp
@@ -0,0 +1,54 @@
+/*
+  Copyright 2019, 2020 SINTEF Digital, Mathematics and Cybernetics.
+
+  This file is part of the Open Porous Media project (OPM).
+
+  OPM is free software: you can redistribute it and/or modify
+  it under the terms of the GNU General Public License as published by
+  the Free Software Foundation, either version 3 of the License, or
+  (at your option) any later version.
+
+  OPM is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "config.h"
+
+#include <opm/simulators/linalg/FlexibleSolver_impl.hpp>
+#include <opm/simulators/linalg/matrixblock.hh>
+
+#include <dune/common/fmatrix.hh>
+#include <dune/istl/bcrsmatrix.hh>
+#include <dune/istl/solvers.hh>
+#include <dune/istl/umfpack.hh>
+#include <dune/istl/owneroverlapcopy.hh>
+#include <dune/istl/paamg/pinfo.hh>
+
+// Explicit instantiations of FlexibleSolver
+
+template <int N>
+using BV = Dune::BlockVector<Dune::FieldVector<double, N>>;
+template <int N>
+using BM = Dune::BCRSMatrix<Dune::FieldMatrix<double, N, N>>;
+template <int N>
+using OBM = Dune::BCRSMatrix<Opm::MatrixBlock<double, N, N>>;
+
+// Variants using Dune::FieldMatrix blocks.
+template class Dune::FlexibleSolver<BM<4>, BV<4>>;
+
+// Variants using Opm::MatrixBlock blocks.
+template class Dune::FlexibleSolver<OBM<4>, BV<4>>;
+
+
+using Comm = Dune::OwnerOverlapCopyCommunication<int, int>;
+
+template Dune::FlexibleSolver<OBM<4>, BV<4>>::FlexibleSolver(const MatrixType& matrix,
+                                                             const Comm& comm,
+                                                             const boost::property_tree::ptree& prm,
+                                                             const std::function<BV<4>()>& weightsCalculator);
+
diff --git a/opm/simulators/linalg/FlexibleSolver.cpp b/opm/simulators/linalg/FlexibleSolver_impl.hpp
similarity index 77%
rename from opm/simulators/linalg/FlexibleSolver.cpp
rename to opm/simulators/linalg/FlexibleSolver_impl.hpp
index 5a1d8e89d..8c19a15e7 100644
--- a/opm/simulators/linalg/FlexibleSolver.cpp
+++ b/opm/simulators/linalg/FlexibleSolver_impl.hpp
@@ -20,6 +20,7 @@
 #include "config.h"
 
 #include <opm/simulators/linalg/FlexibleSolver.hpp>
+#include <opm/simulators/linalg/PreconditionerFactory.hpp>
 #include <opm/simulators/linalg/matrixblock.hh>
 
 #include <dune/common/fmatrix.hh>
@@ -184,48 +185,3 @@ namespace Dune
     }
 
 } // namespace Dune
-
-
-// Explicit instantiations of FlexibleSolver
-
-template <int N>
-using BV = Dune::BlockVector<Dune::FieldVector<double, N>>;
-template <int N>
-using BM = Dune::BCRSMatrix<Dune::FieldMatrix<double, N, N>>;
-template <int N>
-using OBM = Dune::BCRSMatrix<Opm::MatrixBlock<double, N, N>>;
-
-// Variants using Dune::FieldMatrix blocks.
-template class Dune::FlexibleSolver<BM<1>, BV<1>>;
-template class Dune::FlexibleSolver<BM<2>, BV<2>>;
-template class Dune::FlexibleSolver<BM<3>, BV<3>>;
-template class Dune::FlexibleSolver<BM<4>, BV<4>>;
-
-// Variants using Opm::MatrixBlock blocks.
-template class Dune::FlexibleSolver<OBM<1>, BV<1>>;
-template class Dune::FlexibleSolver<OBM<2>, BV<2>>;
-template class Dune::FlexibleSolver<OBM<3>, BV<3>>;
-template class Dune::FlexibleSolver<OBM<4>, BV<4>>;
-
-
-using Comm = Dune::OwnerOverlapCopyCommunication<int, int>;
-
-template Dune::FlexibleSolver<OBM<1>, BV<1>>::FlexibleSolver(const MatrixType& matrix,
-                                                             const Comm& comm,
-                                                             const boost::property_tree::ptree& prm,
-                                                             const std::function<BV<1>()>& weightsCalculator);
-
-template Dune::FlexibleSolver<OBM<2>, BV<2>>::FlexibleSolver(const MatrixType& matrix,
-                                                             const Comm& comm,
-                                                             const boost::property_tree::ptree& prm,
-                                                             const std::function<BV<2>()>& weightsCalculator);
-
-template Dune::FlexibleSolver<OBM<3>, BV<3>>::FlexibleSolver(const MatrixType& matrix,
-                                                             const Comm& comm,
-                                                             const boost::property_tree::ptree& prm,
-                                                             const std::function<BV<3>()>& weightsCalculator);
-
-template Dune::FlexibleSolver<OBM<4>, BV<4>>::FlexibleSolver(const MatrixType& matrix,
-                                                             const Comm& comm,
-                                                             const boost::property_tree::ptree& prm,
-                                                             const std::function<BV<4>()>& weightsCalculator);
diff --git a/tests/test_flexiblesolver.cpp b/tests/test_flexiblesolver.cpp
index a790ce9ea..615ffa9dd 100644
--- a/tests/test_flexiblesolver.cpp
+++ b/tests/test_flexiblesolver.cpp
@@ -29,6 +29,7 @@
     BOOST_VERSION / 100 % 1000 > 48
 
 #include <opm/simulators/linalg/FlexibleSolver.hpp>
+#include <opm/simulators/linalg/getQuasiImpesWeights.hpp>
 
 #include <boost/property_tree/json_parser.hpp>
 #include <boost/property_tree/ptree.hpp>