Diagnostic for Ye Old Damp Passenger Floor Carpet?

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Apr 9, 2017
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tejas
i'm in texas and have had an intermittent damp passenger floor carpet. when i first got the rig it was soaked and i was convinced i had a heater core leak but i eventually realized i had power washed the engine bay and seem to have sprayed a good deal of water at the firewall.
i'm not totally sure how it would have gotten in but that was my determination at the time.
since then i have - maybe a handful of times per year - pulled up the floor mat and found the carpet slightly damp. it was so infrequent i go to the point of keeping my "podium" water squirt bottles and other water bottles off the floor. and it seemed to have gone away.
long story short is i am back on this. is there a good way to diagnose heater core versus AC drain? does a heater core leak occur only when using the heater i guess? and AC drain issue is only when using the AC i suppose. and can a leaking rear heater line cause a damp passenger side floor board? i suppose it can but it would be green or red in color and taste like coolant i suppose?
anyway i finally put a garden hose on it for fifteen minutes today and i didn't find a leak so i took it to the power wash and i didn't find a leak.
as a next step i suppose i run the heater for half an hour and if it is wet i know i need to go in and do a heater core eventually?
also what is failing exactly when a heater core leaks? is it leaking water?
note: i already ran weed wacker
trimmer down the roof drains. also i still need to find the AC drain so if anyone has a picture of where that is i would like to check that.
THANKS for any help
 
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i'm in texas and have had an intermittent damp passenger floor carpet. when i first got the rig it was soaked and i was convinced i had a heater core leak but i eventually realized i had power washed the engine bay and seem to have sprayed a good deal of water at the firewall.
i'm not totally sure how it would have gotten in but that was my determination at the time.
since then i have - maybe a handful of times per year - pulled up the floor mat and found the carpet slightly damp. it was so infrequent i go to the point of keeping my "podium" water squirt bottles and other water bottles off the floor. and it seemed to have gone away.
long story short is i am back on this. is there a good way to diagnose heater core versus AC drain? does a heater core leak occur only when using the heater i guess? and AC drain issue is only when using the AC i suppose. and can a leaking rear heater line cause a damp passenger side floor board? i suppose it can but it would be green or red in color and taste like coolant i suppose?
anyway i finally put a garden hose on it for fifteen minutes today and i didn't find a leak so i took it to the power wash and i didn't find a leak.
as a next step i suppose i run the heater for half an hour and if it is wet i know i need to go in and do a heater core eventually?
also what is failing exactly when a heater core leaks? is it leaking water?
note: i already ran weed wacker
trimmer down the roof drains. also i still need to find the AC drain so if anyone has a picture of where that is i would like to check that.
THANKS for any help
Normally if the heater core is leaking you will smell coolant, get foggy windows and have coolant loss. If you don't have these things its probably not the core. Plugged or detached AC drain line seems to be the more common issue.
 
Joined
Apr 9, 2017
Messages
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Location
tejas
Normally if the heater core is leaking you will smell coolant, get foggy windows and have coolant loss. If you don't have these things its probably not the core. Plugged or detached AC drain line seems to be the more common issue.
thanks man. that's super helpful. appreciate that. so it would be colored coolant leaking out of the heater core then?
 
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Gilbert, AZ
i'm in texas and have had an intermittent damp passenger floor carpet. when i first got the rig it was soaked and i was convinced i had a heater core leak but i eventually realized i had power washed the engine bay and seem to have sprayed a good deal of water at the firewall.
i'm not totally sure how it would have gotten in but that was my determination at the time.
since then i have - maybe a handful of times per year - pulled up the floor mat and found the carpet slightly damp. it was so infrequent i go to the point of keeping my "podium" water squirt bottles and other water bottles off the floor. and it seemed to have gone away.
long story short is i am back on this. is there a good way to diagnose heater core versus AC drain? does a heater core leak occur only when using the heater i guess? and AC drain issue is only when using the AC i suppose. and can a leaking rear heater line cause a damp passenger side floor board? i suppose it can but it would be green or red in color and taste like coolant i suppose?
anyway i finally put a garden hose on it for fifteen minutes today and i didn't find a leak so i took it to the power wash and i didn't find a leak.
as a next step i suppose i run the heater for half an hour and if it is wet i know i need to go in and do a heater core eventually?
also what is failing exactly when a heater core leaks? is it leaking water?
note: i already ran weed wacker
trimmer down the roof drains. also i still need to find the AC drain so if anyone has a picture of where that is i would like to check that.
THANKS for any help

Does your LC have a sun roof? If so have you checked the drain and made sure they are not clogged?
 

brettk

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I might be completely wrong on this, so someone feel free to correct me if need be. Could it be due to sweating? Think of a cold water bottle with condensation on the outside of the bottle. I think it may be where the cat is getting hot, and the cold floorboard is starting to sweat. The jute insulation from underneath the carpet is soaking up the moisture like a sponge, and is causing your wet carpet.

Your cat maybe clogged, but I’m not 100% on that. Just don’t ignore the issue, wet jute is going to invite rust, and that sucks.
 

Njck22

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Lick it. If it’s sweet, with bitter notes, it’s coolant
 
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Leaky rear heater lines would not affect the passenger floorboard.
 
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Your heater core always has coolant in it. If you were to pressure test the cooling system and it drops pressure and your floor starts to get wet, then it's the heater core.

For the evaporator drain, I would let the car idle with the AC on and look on the passeger side underneath the car for water dripping down. You can also peek up under the glove box/ heater box and see if the grommet and evap drain is in place.
 

77mustard40

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I had this issue that I discovered a couple months back, it was the sunroof drains in the front corners. Thorough cleaning of the sunroof drain pan and running 5’ of thick Echo weed eater wire down the holes opened them back up. The drain slots in the quarter panels under the truck were clear. Poured a little water in the sunroof drains and watched it drip out under the truck, Ive been dry even after a couple of big rains.

There’s a pretty good thread on the subject, can’t remember but maybe it’s in the FAQ
 

REKCUT

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In texas, turn on your ac and watch under the truck. You'll see the ac drain fairly quickly
 

REKCUT

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I could use a hose and never get my windshield to leak but it would with a long enough rain. Was a windshield install issue. It will take some time but I removed my front carpet and would patiently watch for signs of water leaks and could track down where it was coming from.
 
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Gateway, CO
As others have already chimed in, there are three most likely culprits: your A/C drain is clogged or not vented through the PS firewall correctly (easy fix); you have clogged sunroof drains (easy fix); or, leaking front heater core (not an easy fix). Also said above, turn on your A/C and see if it drips out the PS firewall. If so, likely not the A/C drain. In terms of location, the drain is in that big gray box under your glove box. You won't be able to open it all the way, but enough to feel the drain hose and put it back in place.

One other issue may be that one of the hoses connecting to the heater core at the firewall may be leaking and running inside the cabin along the core's inlet/outlet.

Someone on here with more knowledge may correct me, but my understanding is that when a heater core fails it's most often due simply to corrosion.

A dye kit would tell you a lot in a hurry.
 

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