I have vent visors on my vehicle that are the glued on type and I had to replace the door, how do I remove the old adhesive from the plastic vent so I can reinstall with new 3M tape

 

My preferred method is the string method. Using a thick piece of string like yarn, you can pull it tight and run it under the visor, then do a sawing motion while pulling it along under the visor, and the string will cut through the tape that's holding it on.

Then just have patients as you clean all the old tape off the visor. The way I usually do that is just with my bare thumb, pushing along and causing the tape to "roll up" on the visor. It's slow going, and chances are your finger will be raw when you're done lol, but it works pretty well. Then just wipe it down with rubbing alcohol, and apply new 3M trim tape. Then wipe down the new door with rubbing alcohol where it's going to be installed and stick it on.


That's how I've gotten all 4 of mine, all from the junk yard, and I'm pretty sure all 4 are different brands off of different donor vehicles lol.

 

If I correctly understand you have already removed the vent-visor? Else for removal blazen_red_red's suggestion is the preferred method.

If it is to remove the remainder of the adhesive/glue/silicone from the visor itself you have to test several solvent based or mechanical methods.
It is a trial-and-error thing and needs some testing on the plastic in order not to use products which will make it brittle or opaque.
When I use solvent based stuff to test, I apply usually on one corner where I want the adhesive to be removed. Treat it as you would for removal, but then go and wash the part in mild soap. Only then you can see if it becomes opaque as slowly evaporating solvents will keep it shiny for quite a while but two hours later you find it opaque.

I usually start out with the mechanical methods which are:

- rubbing/pushing off with your finger (fine for a try, full removal may want to use rubber gloves, else... LOL)
- pencil eraser (The ones with a sand feeling may scratch the plastic. May need plain rubbery ones.)
- tire shop rubber wheel for a drill (some shops have these rubbery wheels to remove the adhesive from the weights on aluminium rims, may be bought from auto-parts stores.)

The solvent based approach I start with:

• Soap and water with a strong paper or rad
• Window cleaner and strong paper or rag
• WD40 (check if it stains the plastic or makes it opaque)
• Gasoline (check if it stains the plastic or makes it opaque)
• Diesel or petroleum (check if it stains the plastic or makes it opaque. best results usually as it is a solvent for many adhesives but leaves that oily surface where the rubbed away glue does not stick to it anymore. For me lamp petroleum showed to be a bad solvent but we can still buy normal petroleum. Diesel also does the trick.

I had the best results with mechanical removal of as much adhesive as possible and remainder with some of the above solvents.

 

thanks good info