Do all the prep work first. Sand lightly with #220 sandpaper. Wash and let dry.

Spackle is less resistant to cracking when the panel expands or contracts.

For best results, prime the groove before spackling. Spackling will adhere strongly to primed surfaces. Fill the groove and then skim over the spackle with the knife at a 45 degree angle to smooth and level it. Allow 24 hours to dry. If sanding is required, use the #220 to smooth it.

Prime then entire surface before painting. Bulls Eye 1 2 3 primer makes a good bond to paneling.

Michael

We have a 1950's ranch house full of mahogany wood paneling...much of it was beyond repair and it looked dried out dated so we painted over it. The grooves add interestto the wall. I used 2 coats of good quality paint in an eggshell finish --Dulux ultra eggshell (it's in a high traffic hallway) and didn't do a darn thing to prep.
When I painted I brushed in the grooves first and then covered quickly with a roller. You could try painting a section first to see if you like the look--you can always go back and fill in, but I bet you won't! Good luck. Can try and include a picture if you think that will help.

I think if you are going to go through the effort of masking/spakleing the grooves... just insall drywall over it!

We just primed and painted our grooved ugly 1980's wood panelling... the walls are painted a deep tan/goldy colour... and the grooves just give it some character... they don't look weird of out of place. We primed with a high adhesive primer and painted with our chosen colour in an eggshell finish....(I was going to post a picture... but in the photos you can't even see the grooves)

OK i filled all the grooves in my panelling before painting.What i want to know is how clean does it have to be before putting primer on. I used drywall compound to fill the grooves.I washed it off after 24 hrs but it looks dusty after washing many times. Is it ok to prime??? or do i have to wash some more OUCH !