diff --git a/CMakeLists.txt b/CMakeLists.txt
index afa88e4a6..f982fe085 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -341,26 +341,6 @@ opm_add_test(flow_onephase
   DEPENDS opmsimulators
   LIBRARIES opmsimulators)
 
-opm_add_test(flow_co2_diffusion
-  ONLY_COMPILE
-  DEFAULT_ENABLE_IF ${FLOW_VARIANTS_DEFAULT_ENABLE_IF}
-  SOURCES
-  flow/flow_co2_diffusion.cpp
-  $<TARGET_OBJECTS:moduleVersion>
-  EXE_NAME flow_co2_diffusion
-  DEPENDS opmsimulators
-  LIBRARIES opmsimulators)
-
-opm_add_test(flow_bo_diffusion
-  ONLY_COMPILE
-  DEFAULT_ENABLE_IF ${FLOW_VARIANTS_DEFAULT_ENABLE_IF}
-  SOURCES
-  flow/flow_bo_diffusion.cpp
-  $<TARGET_OBJECTS:moduleVersion>
-  EXE_NAME flow_bo_diffusion
-  DEPENDS opmsimulators
-  LIBRARIES opmsimulators)
-
 opm_add_test(flow_onephase_energy
   ONLY_COMPILE
   DEFAULT_ENABLE_IF ${FLOW_VARIANTS_DEFAULT_ENABLE_IF}
diff --git a/flow/flow_bo_diffusion.cpp b/flow/flow_bo_diffusion.cpp
deleted file mode 100644
index f93e638de..000000000
--- a/flow/flow_bo_diffusion.cpp
+++ /dev/null
@@ -1,43 +0,0 @@
-/*
-  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/flow/Main.hpp>
-
-namespace Opm {
-namespace Properties {
-namespace TTag {
-struct EclFlowDiffusionProblem {
-    using InheritsFrom = std::tuple<EclFlowProblem>;
-};
-}
-
-template<class TypeTag>
-struct EnableDiffusion<TypeTag, TTag::EclFlowDiffusionProblem> {
-    static constexpr bool value = true;
-};
-
-
-}}
-
-
-// ----------------- Main program -----------------
-int main(int argc, char** argv)
-{
-    using TypeTag = Opm::Properties::TTag::EclFlowDiffusionProblem;
-    auto mainObject = Opm::Main(argc, argv);
-    return mainObject.runStatic<TypeTag>();
-}
diff --git a/flow/flow_co2_diffusion.cpp b/flow/flow_co2_diffusion.cpp
deleted file mode 100644
index 8b4fe9a95..000000000
--- a/flow/flow_co2_diffusion.cpp
+++ /dev/null
@@ -1,64 +0,0 @@
-/*
-  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/flow/Main.hpp>
-#include <opm/models/blackoil/blackoiltwophaseindices.hh>
-
-namespace Opm {
-namespace Properties {
-namespace TTag {
-struct EclFlowCo2Problem {
-    using InheritsFrom = std::tuple<EclFlowProblem>;
-};
-}
-
-template<class TypeTag>
-struct EnableDiffusion<TypeTag, TTag::EclFlowCo2Problem> {
-    static constexpr bool value = true;
-};
-
-//! The indices required by the model
-template<class TypeTag>
-struct Indices<TypeTag, TTag::EclFlowCo2Problem>
-{
-private:
-    // it is unfortunately not possible to simply use 'TypeTag' here because this leads
-    // to cyclic definitions of some properties. if this happens the compiler error
-    // messages unfortunately are *really* confusing and not really helpful.
-    using BaseTypeTag = TTag::EclFlowProblem;
-    using FluidSystem = GetPropType<BaseTypeTag, Properties::FluidSystem>;
-
-public:
-    typedef Opm::BlackOilTwoPhaseIndices<getPropValue<TypeTag, Properties::EnableSolvent>(),
-                                         getPropValue<TypeTag, Properties::EnableExtbo>(),
-                                         getPropValue<TypeTag, Properties::EnablePolymer>(),
-                                         getPropValue<TypeTag, Properties::EnableEnergy>(),
-                                         getPropValue<TypeTag, Properties::EnableFoam>(),
-                                         getPropValue<TypeTag, Properties::EnableBrine>(),
-                                         /*PVOffset=*/0,
-                                         /*disabledCompIdx=*/FluidSystem::waterCompIdx> type;
-};
-}}
-
-
-// ----------------- Main program -----------------
-int main(int argc, char** argv)
-{
-    using TypeTag = Opm::Properties::TTag::EclFlowCo2Problem;
-    auto mainObject = Opm::Main(argc, argv);
-    return mainObject.runStatic<TypeTag>();
-}