No not at all......the outer diameter of the tubing i bought is a hair less than the aluminium tubes ID and the sidewall thicknesss is around 1 mm, but its fairly stiff, (can be coiled without kinking) so can be pushed through the aluminium without bending, or thread a wire through each tube from the engine bay side and attach to nylon tubing and pull through. Any place that sells piping, tubing, hosing, etc will have something that works....very cheap and permanent fix. I also tightened my hose clamps onto the nylon tubing as well as the aluminium tubing each end to ensure no seepage can occur between the tubes and into the tray well area. The nylon tubing extends roughly 3 cm past each end of the aluminium tubing. So I use two hose clamps for each end