M1009 Water leak

Hello all. My 85 M1009 has a pretty big water leak coming from behind the dash on the passengers side. Any ideas on where to start looking to find the source of the leak? I came out this morning and there was an inch of water pooled in the corner of it. Any help or ideas would be greatly appreciated.

if your talking about coolant leaking its from your heater core.

It is just rain water. Monsoon season is back. My heater runs just fine.

If you are talking about straight water I would check your windshield seal by running a hose in that area and looking for the leak. If it is the windshield you will need to pull it out and reseal or you could hack it by trying to slobber caulk in the area of the suspected leak. I would do it right with reinstalling the windshield but this is a very delicate job that I would leave to someone else. Getting the windshield out in one piece is not as easy as it sounds.

If it is coolant I second Westech. Time for a heater core. Do you smell a sweet smell in the truck and does the windshield fog up when you turn on the heater? These are clear signs of a leaking heater core.

Oops. You replied to fast. Windshield is leaking unless you have some bad rust holes somewhere. BTW the heater will work just fine even when leaking. At least until you run out of coolant.

lotsa caulk

"hack it by trying to slobber caulk in the area"

NICE!!!