I'm going to tape off the sunroof on my wife's car to find out if that's the source of a leak. I'll need to leave it in the rain for a couple days.

Is there any particular kind of tape I should be using so as not to damage the paint? I also want a kind of tape that would be water-resistant to completely seal off the sunroof.

(BTW, it's not the mini, but another car she owns--figured the responses could be potentially helpful here as well)

 

Blue painter's tape. I've used it to mask off the vinyl stripes while running the random orbital for polishing. Just don't leave it for more than a day or two.

 

+1 blue painter tape, guys like it for Auto X protection from rocks and such.

 

Blue painters tape should be safe for the paint, but I'm not sure if it will hold in the rain, or keep the water out of the sunroof jamb/drains.

 

+1 on blue painter tape and ... maybe duct tape over the blue tape (and ONLY over the blue tape).
Just for 2 or 3 days.

 

Check with an auto glass shop since they regularly tape in replacement windshields. I'd throw down a coat of wax prior to your tape-job.

 

you could always put down vinyl to get a better seal (can find at most craft stores)

 

I went in to the local auto parts store and they had green tape they suggested I use. It has the feel of masking tape or painters' tape, and I don't know if there's any real difference.

 

3M Automotive Performance masking tape? No worries.

 

If the green they showed was 3M you might want to review this 3M chart ...

the green is great for masking as it provides a cleaner 'edge' than blue and can be removed 'clean' after much longer

... BUT

It has LESS holding strength (important if you plan to drive with the tape on the car vs. just letting it sit in rain) and a lower temperature resistance (200 vs 250) which can be important if the car will be sitting in the sun and has a dark color roof . . .

I think the green costs more ... but may not be better for your application.

I would not use a plastic tape or duct tape .... I know "masking tape" is safe but dunno about the other stuff

If not 3m tape .... Google Green Masking Tape ..... I got a bunch of articles about comparisons to blue . . .

I'd use Blue 3M .... actually I did in the past for a similar application. After having the windshield replaced on a Honda Element TWICE ... I still got a wind whistle above 50 mph. I used blue masking tape over the seal to identify the exact problem area (and SAFELITE replaced the glass a third time - no extra charge - and used a different gasket material which solved the problem)