Water In Tray Under Rear Window

[Tulecreeper]

I thought I would toss this out there for anyone who thinks their rear window might be leaking but can't find where it's coming from.

A couple weeks ago, I bought a gallon of the concentrate OAT coolant (yes, I got the correct one) and mixed up 2 gallons of 50/50 mix, then I put a gallon in the plastic tray behind the seat under the rear window and stuffed a small folded blanket in front of it to keep it from moving. Two days ago (Monday) I had to use the blanket to wrap around some fluorescent light bulbs I was carrying in the bed and I didn't want to have that gallon flopping back and forth so I pulled it out to set it in the front seat for the ride. The outside of that jug was wet, and there was about 1/2 cup of liquid under it in the tray. I touched it and smelled it, but it was just water. I dried it off, mopped it up, and tested it again that night and yesterday morning it was the same. I pulled the jug, dried it off, and set in in the garage overnight and looked at it again this morning and it's dry...and there is no water in the tray behind the seat.

Short story - the jug is not leaking. The jug is condensing a lot of water out of the air in the cab of my truck and pooling in the tray but not doing it in the garage. I've carried extra coolant behind the seats of every truck I've owned and never seen this happen before. Anyone got a clue what's happening?

 

[mikeru]

I'm trying to envision this tray you're talking about, then I noticed you have a HD truck. Which makes me assume HD's have a tray behind the rear seat LOL. There is no tray behind the rear seats in a 1500, and the majority of people with rear window leaks are 5th gen 1500 owners.

You obviously have moisture in the cab of your truck which is condensing on the outside of the jug. That can be because of a leak of course. It can also be from dragging snow or water from your feet into the cab when getting in. It takes longer in winter for your cab to dry out. There are desiccants for car interiors to help with this. Linky...

Amazon.com : car desiccant

 

[mrack]

OP has a single cab, they have a plastic tray behind the seats. I’d pull the carpet off the back wall and check your cab vents to be sure, doesn’t take but 20 minutes.

 

[Dodge 1500 4X4]

Rear window leaking is the frame cracked or drain holes clogged or cab vents, If the headliner is wet I would suspect the CHMBL.

 

[Tulecreeper]

I'm trying to envision this tray you're talking about, then I noticed you have a HD truck. Which makes me assume HD's have a tray behind the rear seat LOL. There is no tray behind the rear seats in a 1500, and the majority of people with rear window leaks are 5th gen 1500 owners.

You obviously have moisture in the cab of your truck which is condensing on the outside of the jug. That can be because of a leak of course. It can also be from dragging snow or water from your feet into the cab when getting in. It takes longer in winter for your cab to dry out. There are desiccants for car interiors to help with this. Linky...

Amazon.com : car desiccant

It's a regular cab, no rear seats. I understand about dragging wet feet into the cab, but that happens with every vehicle and I have never had a jug condense like that before. It's a mystery.

 

[Tulecreeper]

OP has a single cab, they have a plastic tray behind the seats. I’d pull the carpet off the back wall and check your cab vents to be sure, doesn’t take but 20 minutes.

Rear window leaking is the frame cracked or drain holes clogged or cab vents, If the headliner is wet I would suspect the CHMBL.

I checked, nothing is leaking. It's just some weird atmospheric phenomena in this particular truck causing condensation on the jug.

 

[Dodge 1500 4X4]

You know what I'm thinking is your jug of the concentrate when you mixed it with distilled water, this water is sweating on the outside of the jug, put your jug of concentrate back there and see if it sweats, I do the same thing, but I put the concentrate back there, maybe its climate change in your Fine State of Arkansas!!!!! W the Chinese fleeing.

 

[mikeru]

I checked, nothing is leaking. It's just some weird atmospheric phenomena in this particular truck causing condensation on the jug.

There's noting mysterious about it. You can't have condensation without moisture and a cool surface. Humid air combined with low temperatures are what is causing it.

 

[Tulecreeper]

There's noting mysterious about it. You can't have condensation without moisture and a cool surface. Humid air combined with low temperatures are what is causing it.

I understand the science, I've just never seen it before and I've always carried a jug of coolant behind the seat in my other trucks. And since everything in the front of the truck is the same temp as the jug - like my vinyl dash and rubber floor mats - why aren't they showing condensation? I just find it odd.

 

[Gewil]

I would suspect third brake light gasket. My 2011 quad cab and my son's 2009 crew cab both had water in the back seat area and resealing the light took care of it.

 

[CaptCurt]

I thought I would toss this out there for anyone who thinks their rear window might be leaking but can't find where it's coming from.

A couple weeks ago, I bought a gallon of the concentrate OAT coolant (yes, I got the correct one) and mixed up 2 gallons of 50/50 mix, then I put a gallon in the plastic tray behind the seat under the rear window and stuffed a small folded blanket in front of it to keep it from moving. Two days ago (Monday) I had to use the blanket to wrap around some fluorescent light bulbs I was carrying in the bed and I didn't want to have that gallon flopping back and forth so I pulled it out to set it in the front seat for the ride. The outside of that jug was wet, and there was about 1/2 cup of liquid under it in the tray. I touched it and smelled it, but it was just water. I dried it off, mopped it up, and tested it again that night and yesterday morning it was the same. I pulled the jug, dried it off, and set in in the garage overnight and looked at it again this morning and it's dry...and there is no water in the tray behind the seat.

Short story - the jug is not leaking. The jug is condensing a lot of water out of the air in the cab of my truck and pooling in the tray but not doing it in the garage. I've carried extra coolant behind the seats of every truck I've owned and never seen this happen before. Anyone got a clue what's happening?

I was getting water through the rear of my Gen4 (09) into the storage areas under rear seat. Took awhile, but the water was coming in through the upper rear brake/bed light on the cab. I took clear silicone and tan a bead of it from bottom left, over top, to bottom right. Has been good ever since, that was in 2012.

 

[mikeru]

And since everything in the front of the truck is the same temp as the jug - like my vinyl dash and rubber floor mats - why aren't they showing condensation? I just find it odd.

Because your vinyl dash and rubber floor mats aren't filled with a cold liquid. If the humidity were high enough and the temperature low enough, you can get condensation on just about any surface that doesn't absorb moisture. Which is how you get dew on your car depending on what the dew point is.

 

[Dusty]

I understand the science, I've just never seen it before and I've always carried a jug of coolant behind the seat in my other trucks. And since everything in the front of the truck is the same temp as the jug - like my vinyl dash and rubber floor mats - why aren't they showing condensation? I just find it odd.

Any damp odor in the truck?

Do you do a lot of short trips and/or little heat in the cab? You could be building up moisture in the cab over time and not realize it.

Also, just for the heck of it, pull up the factory front floor mat or carpet and check for water.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 106202 miles.

 

[Marshall]

just take the jug back out for a few days and see if the tray is still dry.
Wonder if you wrapped the jug in a large garbage bag or two if that would work as a insulator?

 

[Tulecreeper]

Any damp odor in the truck?

Do you do a lot of short trips and/or little heat in the cab? You could be building up moisture in the cab over time and not realize it.

Also, just for the heck of it, pull up the factory front floor mat or carpet and check for water.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 106202 miles.

No, sir...no damp odor.

 

[Tulecreeper]

just take the jug back out for a few days and see if the tray is still dry.
Wonder if you wrapped the jug in a large garbage bag or two if that would work as a insulator?

I did, it stays dry.

 

[Tulecreeper]

Because your vinyl dash and rubber floor mats aren't filled with a cold liquid. If the humidity were high enough and the temperature low enough, you can get condensation on just about any surface that doesn't absorb moisture. Which is how you get dew on your car depending on what the dew point is.

Not agreeing with that hypothesis. The jug isn't filled with cold liquid, either. Once I put it in the truck and a short period of times goes by, the temp of it and everything else in that small space rises and falls at the same rate. It's in a controlled environment that is pretty much sealed away from atmospheric water vapor. The hood of your truck is outside, exposed to lots of water vapor, in an environment that warms and cools faster than the metal can keep up.

 

[turkeybird56]

I keep this in my center console of my 1500 ref moisture:

 

[mikeru]

Not agreeing with that hypothesis. The jug isn't filled with cold liquid, either. Once I put it in the truck and a short period of times goes by, the temp of it and everything else in that small space rises and falls at the same rate. It's in a controlled environment that is pretty much sealed away from atmospheric water vapor. The hood of your truck is outside, exposed to lots of water vapor, in an environment that warms and cools faster than the metal can keep up.

Agree or not, you're free to have your own opinion. Just know that the contents of the jug do not change temperature as fast as the air surrounding it. Liquids always change temperature much slower than air. I hope you're not trying to claim that you have some kind of weird unexplainable phenomenon going on. It's simple. Absent any leaks on your jug, and you've already said your cab has no leaks to drop onto the jug, if moisture forms on the outside of the jug it's absolutely caused by condensation. Since it's inside your cab when this happens, the environment inside your cab has a high enough level of humidity for it to condense on the jug. No other explanation needed.

 

[Tulecreeper]

Agree or not, you're free to have your own opinion. Just know that the contents of the jug do not change temperature as fast as the air surrounding it. Liquids always change temperature much slower than air. I hope you're not trying to claim that you have some kind of weird unexplainable phenomenon going on. It's simple. Absent any leaks on your jug, and you've already said your cab has no leaks to drop onto the jug, if moisture forms on the outside of the jug it's absolutely caused by condensation. Since it's inside your cab when this happens, the environment inside your cab has a high enough level of humidity for it to condense on the jug. No other explanation needed.

No, I know what's going on. It's condensation, plain and simple. I only said I have carried jugs of coolant behind the seats of every truck/vehicle I've owned and never even heard of this happening before. That's all.