Have you got one of those plastic repair kits that come with the super glue and powder handy.
I have used this stuff to fix a mounting on my headlight and even fixed a plastic sprinkler with it and both are still going strong [thumbsupbig]
Q-Bond QBond Plastic Repair Kit, Glues Grilles Bumpers Body Clips KE70 AE86 S13 | eBay
Maybe some PVC glue would do the trick but I am not sure if the diesel would affect the glue or not.

