Hi @jwamb ,
Here’s a link to the [https://topics-cdn.dell.com/pdf/latitude-e5440-laptop_owners-manual_en-us.pdf|service manual] for your laptop.
Scroll to the bottom of p.29 to view the necessary pre-requisite steps and then the procedures to remove the system fan so that you can clean it and the vents.
You may also use the opportunity when you have dis-assembled that laptop this far to remove/ replace the thermal paste that is covering the CPU, as the old application of paste has no doubt dried out and is not as effective. Be careful as you do this so as to not damage anything. As always with electronics be gentle. ;-)