Dusty roads

[surfcam]

My Mk3 Jetta fills up with dust when I drive down gravel roads. It seems to be coming in through the back seat from the trunk? I noticed some kind of air check valves under the rear bumper. Maybe they have failed. Should I just duck tape them shut? This car also took a hit on the passager rear tail light and was patched-up by the P.O.

[TylerDurden]

Most sedans have a negative pressure area starting at the end of the roof, and extending around the entire tail. It's common to see the dryer vent style flaps hiding inside rear bumpers, that allow pressure to puff out when doors & hatches close, but don't let fumes in while driving.

I'd check the trunk seals and any other areas where air can infiltrate, and keep the blower running to pressurize the cabin.

[bscutt]

Or you may have rust holes you don't know about. My floor pan replacement has turned into a challenging 7+ week task. Found a few hidden holes along the way.

[surfcam]

You guy's have raised some good points for me to look at. This car did come from the rust belt (Ontario). Now that I think about it. There's been dirt now and again and one time mud balls showing up in the trunk. I hope I don't end up like Fat's if the trailing arm decides to let's go.

[Fatmobile]

Me too.
RIP Old Blue, ha.

[surfcam]

I finally got around to taking out the trunk liner and have a look see. There's a huge hole in the wheel well around the diesel filler neck and above it that's easy to see. Inside the trunk you can feel the hole but it's hard to see because there's some kind of support structure in front of it. The P.O. had a plastic bag with a piece of foam shoved into the hole (rust belt technology). I was thinking of screwing some plastic to the inside of the wheel well and then fill the other side up with foam from inside the trunk maybe that will stop the mud balls from coming in?

[bscutt]

yeah mine was somehow not letting in dust that I could tell but I have found some nasty hotes. Have most patched now but it's still a work in progress. Ran water over the car tonight and it wa slike someone opened a faucet to the passenger side front. That will be one of tomorrows tasks to get resolved

[surfcam]

Fun that I'm hitting my car with a hose as well. Try clean all the dust and dirt out of her. Getting read for some kind of patch. Part of a plastic wheel well would be good. Finding one to fit might be another matter.

[bscutt]

found my leak today. Apparently about 8 or 9 years ago when I changed out my heater core and had to remove the whole plenum from the rain tray, I failed to get one small area recaulked right under the valve that runs the fresh air/recirc vent. So today I found it, was able to move the vacuum valve out of the way, and used brush on seam sealer (using lots on the floor pan rebuild) and was able to get that hole filled up. Once that cures it will get some Flex Seal sprayed over that just for good measure. I guess that was a big contributor to my floor plans rusting out. So before any sound deadener or carpet goes in I fill do a good test for leaks from above and also from below. This chasing rust stuff is incredibly hard and time consuming to fix. I'll be happy when I find the last place to fix and get it done.

[TylerDurden]

I was thinking of screwing some plastic to the inside of the wheel well and then fill the other side up with foam from inside the trunk maybe that will stop the mud balls from coming in?

I would avoid foam on any panel interior, it seems to hold water against the metal for rapid rust generation.

I'd seal a patch on the outside and spray bedliner or undercoating on the inside & out.

[surfcam]

I spend a little time on utube watching people fix rust problems. There's a guy promoting POR15. It's just a expoxy in a two part putty form. They never heard of it where I live so I bought some Tech Steel which resembles the POR15. The hole is about 2 1/2 x 4 inches. I'm going to put the Tech Steel on a patch of something and use steel stud screws to hold it on. I love steel stud screws because they are self starting with their sharp tips. Your probably right about the foam. I think I remember vans that were spray on the inside and had problems. I wish I could get to this job and get it done. Now my wife who doesn't drive want's to go three hours the High River to bid on a barbie. I guess it will be fun to see how much she goes for. I wasn't making much headway anyway with everybody come over with they problem vehicles. Ever done a tune up on 1913 International truck me either but it looks niece. Lot's of brass on that baby.

[bscutt]

POR 15 is awesome stuff. I have used over a quart on the floor pan replacement (see Projects). They make a variety of products now besides the paint including metal prep and various other body work products. I got as much rust off this thing as I could and painted about 3 coats of the POR15 paint inside and 2 on the bottom so far. It cures into pretty tough stuff.

[surfcam]

While I final got around to fixing the hole in the wheel well and was successful. I used some plastic out of a 3 pound honey bucket. The round side worked well for the round wheel well. I used some PL 400 (joist glue). I cut some more plastic to go around the fuel filler neck as well. I just used some acrylic around the gas cap. I did this on my 91 jetta and it lasted. Dirt was flying up all over the gas cap. I've heard that the Mk 3 have rust problems and I can confirm that in this case.