diff --git a/src/test/libslic3r/test_printgcode.cpp b/src/test/libslic3r/test_printgcode.cpp
index ee669d01a..34c529ed6 100644
--- a/src/test/libslic3r/test_printgcode.cpp
+++ b/src/test/libslic3r/test_printgcode.cpp
@@ -45,6 +45,9 @@ SCENARIO( "PrintGCode basic functionality") {
                 REQUIRE(exported.find("; support material extrusion width") == std::string::npos);
                 REQUIRE(exported.find("; first layer extrusion width") == std::string::npos);
             }
+            THEN("Exported text does not contain cooling markers (they were consumed)") {
+                REQUIRE(exported.find(";_EXTRUDE_SET_SPEED") == std::string::npos);
+            }
 
             THEN("GCode preamble is emitted.") {
                 REQUIRE(exported.find("G21 ; set units to millimeters") != std::string::npos);
diff --git a/xs/src/libslic3r/PrintGCode.cpp b/xs/src/libslic3r/PrintGCode.cpp
index 3fc7f0127..72f3ff03c 100644
--- a/xs/src/libslic3r/PrintGCode.cpp
+++ b/xs/src/libslic3r/PrintGCode.cpp
@@ -659,6 +659,8 @@ PrintGCode::process_layer(size_t idx, const Layer* layer, const Points& copies)
         copy_idx++;
     }
     // write the resulting gcode
+    gcode = this->_cooling_buffer.append(gcode, std::to_string(reinterpret_cast<long long unsigned int>(layer->object())) + std::string(typeid(layer).name()), 
+                                         layer->id(), layer->print_z);
     fh << this->filter(gcode);
 }