Need Help Fast, Got To Have My Truck Up Tomorrow

[ZWilson07]

Well I finally cut off the foam insulation from the firewall underneath the e heater box. I tried to get as close and under the heaterbox as best I could but it dont leave much room.

I guess my best bet is to just drive the truck with the flooring out and stuff and if it leaks then obviously its from the truck. Then the next time it rains, if it comes in; I know its obviously leaking in from rain and I can hopefully get more of an idea of where its coming from.

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On a site note, that rubber plug held the rubber foam on and broke when I pulled the insulation, can that leak in there or does that even go all the wall through the firewall?

Also does the heaterbox cover need to be completely sealed? There was sealant all the way around it even though it gets bolted closed so I didn't know if that was to prevent fumes from coming in or what?

 

[LCAM-01XA]

That seam you see there, mine was gone. But this is a good plan you have, best way to identify location of leak is to actually see it or the wet tail. Go ahead and put your dash back together too, it won't get in the way of your leaks observations.

The rubber plug goes all the way thru. Excellent location for running wires thru firewall - enlarge hole, insert grommet, feed wires thru it. Pretty sure it won't leak, but if you want to you can always smear some rtv in the hole of it an thus make it a solid plug. Tho dunno how long I had mine missing entirely and I still got no leaks thru the open hole.

Sealant on heater core plenum cover does go all the way around. It's against air leaks mostly (so all hot air goes thru vents), but I suspect in case of heater core rupture it will also prevent coolant from leaking on carpet. At least for a while. When I did my heater core I used GE 3-hour silicone - seals well and easy enough to remove in the future if need arises.

 

[ZWilson07]

What about the cover for the heaterbox?

Is that something that needs to be sealed or can it just be bolted back up? It had silicone on it when I pulled it out but I dont know if thats just some any fumes down makes it way in or what. I dont know if it would be bad to drive without the cover back on and just the heater core sitting there open.

 

[ZWilson07]

BUMP?

 

[LCAM-01XA]

Driving w/o cover gives you no heat out the vents, it will just come out the open plenum. I siliconed my cover to minimize air leaks and allow all the air passing thru the core to be directed where it needs to go thru them vents. Simply bolting cover on w/o any seal may allow some air to escape thru the cracks and thus reduce what you see at the vents. And there are no fumes to enter the passenger compartment that you should be worried about, and even if there were remember the heater plenum opens up to the vents so you'd be inhaling said fumes regardless.

 

[ZWilson07]

Driving w/o cover gives you no heat out the vents, it will just come out the open plenum. I siliconed my cover to minimize air leaks and allow all the air passing thru the core to be directed where it needs to go thru them vents. Simply bolting cover on w/o any seal may allow some air to escape thru the cracks and thus reduce what you see at the vents. And there are no fumes to enter the passenger compartment that you should be worried about, and even if there were remember the heater plenum opens up to the vents so you'd be inhaling said fumes regardless.

I ended up just bolting it back on without sealing it for now atleast and til I can get an idea about where water is coming in from.

I have a single cab so I really never have any problems with not getting enough heat lol, but if that did become a problem id know why. Appreciate it.