Leak under dash in 78 Chinook

[george101]

Hello,

I was wondering if anyone has experience with leaks under the dashboard of a 78 Chinook.

I was driving yesterday and we had a pretty good rain coming down. A consistent drip started hitting my foot by the driver's pedal. So, I narrowed the leak area down to that little vent area in front of the wind shield by the wind shield wipers. I found this little square compartment that you can unscrew from the engine compartment. You can stick your hand into the square compartment and reach the vent area.

There I found enough soil to plant a tree.

I guess leaves and stuff have been piling up there since 1978 and just have been deteriorating there. SO I presumed if I just removed all the soil, or as much as I could get, then this would unclog some sort of drainage hole and fix my problem. But I removed as much of the dirt as I could get and then sprayed it with a hose, but still had leakage. I guess there's a possibility that I just didn't get enough of the dirt out to clear the drainage hole?? But, feeling around in there I didn't actually feel anything that I would say would be a drainage hole for sure.

Has anyone had this problem before? If so, did you find a solution?

Thanks,

George

[george101]

Ok, so I think I figured out why it's leaking. So, I believe it's meant to drain in two places. It drains inside the door and in heavy rains, if the drainage through the door backs up, it drains out of the hinge for the hood. So, if you let leaves and other misc junk build up in there then it will mainly drain out of the hinge. So when it drains out of the hinge there's a spot for a wire entrance into the dash directly below the hinge. If this is not sealed tight, then the water drains through the opening for the wires and directly into you dash. Awesome. But it's an easy fix. Just cock up that spot where the wires enter. Also, on my chinook, on the side where the wiper motor was, there was a drilled hole for another wire. So cock that as well.

However, be VERY careful when you take out the piece on the left side where the wind shield wiper motor is. Because, you could be an idiot like me and accidentally drop the motor and snap off the little plastic connector piece to the wind shield wipers. Then you've got a whole new problem.

[Gulfstream Greg]

The cowling (vent holes) just behind the hood will remove and give you access to the area. I believe the water is supposed to drain to the sides between the fender and firewall area. If its dripping on your foot it sounds like you have a rust hole somewhere.

[krj]

Could be dry rot of weather striping as well; this is a 32 year old rig we're talking about.

I had a '78 Chinook that spent her life in the desert. Once I brought her up to the wet N.W. I noticed a bunch of leaks in wet weather. Once I looked closer ALL the weather stripping was dry rotted; rain would come in both doors and puddle in the cab.

If you want to fix it I'm pretty sure you can get new weather striping kits for these trucks from JC Wittney or other sources. Good luck, stay dry.

Kevin