diff --git a/include/cantera/transport/GasTransport.h b/include/cantera/transport/GasTransport.h
index d83863d5c..e754d2c8e 100644
--- a/include/cantera/transport/GasTransport.h
+++ b/include/cantera/transport/GasTransport.h
@@ -129,7 +129,7 @@ protected:
     /*!
      * These are evaluated from the polynomial fits of the temperature at the unit pressure of 1 Pa.
      */
-    void updateDiff_T();
+    virtual void updateDiff_T();
 
     //! Vector of species mole fractions. These are processed so that all mole
     //! fractions are >= MIN_X. Length = m_kk.
diff --git a/src/transport/GasTransport.cpp b/src/transport/GasTransport.cpp
index 371c05f1e..e0fb03e96 100644
--- a/src/transport/GasTransport.cpp
+++ b/src/transport/GasTransport.cpp
@@ -131,6 +131,8 @@ bool GasTransport::initGas(GasTransportParams& tr)
     m_viscwt_ok = false;
     m_spvisc_ok = false;
     m_bindiff_ok = false;
+
+    return true;
 }
 
 void GasTransport::update_T(void) {