Ok, a genuine C7 question!

[KenHorse]

We just got through 4+ days of sub-freezing temps (never got above 24 and went as low as 14) and, after things started thawing out, I noticed a small amount of what appears to be coolant (has the reddish tint to it) on the floor. As you see in the attached pics, it's not much and seems to have originated on the passenger side, about 1 foot in from the side skirts.

First thought (of course) is cracked block or split hose. So I started it up (fired right up) and brought it up to running temp with no further evidence of escaping fluid of any kind. I checked what I could without getting under the car and there's no sign of leakage that I can see. Also, the TPMS on that corner is reporting as low (21 psi) and a pressure gauge says 22.5 (close enough)

We've been through freezing temps before with this GS (2019 model) and I've never seen this until now.

Thoughts?

[LATB]

Thoughts?

Trade it on an EV.

[KenHorse]

Don't want a CorVolt

Next?

[Steve_R]

Is that behind the door? It’s hard to tell from the pictures. If so I don’t think there’s any hoses or lines with coolant there. Mine has sat outside in temps much colder than that and nothing leaked.

[KenHorse]

This is the passenger side. The joint you see is the door's leading edge

[Steve_R]

The coolant surge tank is right above that.

[KenHorse]

I was thinking that too. Is there an overflow for that tank?

[lrobe22]

Sell it and buy a better brand.

[KenHorse]

Originally Posted by lrobe22

Sell it and buy a better brand.

Do tell

[lrobe22]

Originally Posted by KenHorse

Do tell

@GrandSportC3

[Steve_R]

Originally Posted by KenHorse

I was thinking that too. Is there an overflow for that tank?

Yup. Gotta be what it was from. Have you filled or checked it recently? Is the cap tight?

[KenHorse]

Haven't filled it recently but haven't checked either. I will tomorrow.

If that is the source, the mechanism behind the "leak" intrigues me

[Tpatt]

See it often on class 8 trucks. Damn cold water leaks. Usually just snug up a hose clamp and its gone. Seen it happen on some at 40* and others at 20* and below

[roadpilot]

I would check under the hood. You could see or still feel the
coolent where it has been leaking. My guess just a loose hose
connection ( and a little bit of tightening and all good).
Let us know what you find out.
Another guess.....was your rad. over filled?

[KenHorse]

After checking around the overflow tank, I don't see any loose hose clamps nor is the cap loose. So I brought the engine up to operating temp again and no signs of any leakage whatsoever.

Curiouser and curiouser.....

[Steve_R]

So, any update, or did you throw the towel in until it leaks again?

[Ronins2ndCuzzin]

Kind of looks like tranny fluid to me. Trans cooler lines go from back to front, and or it could be fluid seeping past the fittings. Really hard to say without being under the car to look for myself. But honestly, if it was that small amount of fluid, and it was only that one time...I wouldn't worry about it again until I saw more fluid. It could've been a freak thing due to temps.

[KenHorse]

Originally Posted by Steve_R

So, any update, or did you throw the towel in until it leaks again?

I checked hoses/clamps and overflow tank cap and all look fine. No further signs of leakage and have driven it a couple times since. Go figure!

Originally Posted by Ronins2ndCuzzin

Kind of looks like tranny fluid to me. Trans cooler lines go from back to front, and or it could be fluid seeping past the fittings. Really hard to say without being under the car to look for myself. But honestly, if it was that small amount of fluid, and it was only that one time...I wouldn't worry about it again until I saw more fluid. It could've been a freak thing due to temps.

Actually, I believe both the tranny and differential coolers are in the back. Not to mention I have a 7 spd

[KenHorse]

Took the car into my local Discount Tires today (no fluid leaks) and they found the tire leak was VERY slow and along the inside edge bead. They said something about the bar code was very close to the area and that sometimes causes a leak. As the tires has been on the car for well over a year, I'm theorizing this recent snap of VERY cold temps (down to the low teens) for several days maybe had something to do with the wheel contracting enough to open the leak and, once opened, didn't complete seal back up when the temps rose. Anyway, that's my story and I'm sticking to it.

So they pulled the tire, cleaned up things and applied some sort of bead sealant. We'll see if the tire holds air over the next few days

[justaguy]

You can usually SMELL a coolant leak. Like the old days when the heater core leaked into the passenger compartment , ugh