When I check the coolant, I see some drips under the car

When I remove the blue cap in the rear trunk to check the coolant, I get some drips under the car, right under where the cap is. Occasionally some coolant will come out when I remove the cap and go down the overflow drain, but the last couple times this didn't happen yet I still see some drips. I only check when the car is cold. I remove the cap slowly and hear some hiss as some air under pressure escapes. The coolant level is pretty much maxed out. Why would this only happen when I remove the cap? I went on a long drive yesterday and that area was bone dry. I checked the floor this morning and it was still dry. I removed the cap to check the coolant and a few drips appeared on the floor, right under the cap. I crawled under and looked up, it was clearly coming from the area where the cap is. I wasn't able to pinpoint the exact location from that vantage point. If there were a bad hose or bad connection or something there would be drips all the time. So why only when I check the coolant? Is it because it's so full?

Coolant bottle? You need to remove the panel/cover to check for leaks either from the bottle or the hoses from the bottle. Sent from my SM-S908U using Tapatalk

Well, sure, but why does it only happen the moment I remove the cap?

I just checked again, this time it didn't drip. This time there was no pressure release, as it was released the first time I checked it. It just seems really strange that it drips as the pressure is being released and never any other times.

I never open mine unless off for several days . That is the only way to check true level. Pressure remains in the system quite some time , when you open the cap due to pressure variance in tank and air it can push liquid out , or actually vaporize and then cool to a liquid , which is what you may be seeing ?

If you mean it can push liquid (or vapor) out of the inlet, no, that's not what I'm seeing. I've seen that in the past, but not this time. The leak is coming from somewhere behind the panel that holds the oil and coolant inlets. There's a hose from the inlet to a coolant container, it's somewhere around there. But if that hose or container had a leak, I'd see the drips on the ground all the time. It only leaks the moment I remove the cap, and then only if there's some pressure inside. That's what's odd about this. I can't think of an explanation for that.

If there is pressure in the system and the cap in the trunk is opened a small amount of coolant will escape and drain from the tube whose opening is located below the oil and coolant caps. The tube empties directly below and will leave a small puddle under the car. If the cap is opened after the car is 100 percent cool this will not happen.

Thanks, but this is not what is happening. I've seen that before, it's nothing to worry about. But the fluid is not coming out the inlet and then draining down the tube. It's coming out behind the panel that holds the oil and coolant inlets, in the engine compartment somewhere, perhaps somewhere along the hose that connects the inlet to the coolant container or other hose or connection in that area.

There is a drain where the oil and coolant reservoirs are. When you open the coolant cap and the coolant is beyond the max level, a little of the coolant would spill out and drain down to the bottom of the car. You can check it by pouring a little water into the reservoir compartment, you will see the water drains onto the floor right below the coolant reservoir. It looks like the issue you have is that your coolant level is too high. You might want to suck out the extra coolant until it is below the max level.

Thanks for your advice, but as I mentioned above, this is not what's happening. I've seen this happen in the past, it's nothing to worry about. It was the first thing I thought of when I saw the drips on the floor. But it's not where it's leaking now.

Why are you checking the coolant level? Did you get a low-coolant warning?

See this thread: Coolant leak - can it wait? Hi, I brought my '08 Cayman S for service and they are reporting a coolant leak. I see coolant residue, but it's dry so it's possible it been there a long time. There's no coolant on the garage floor and the coolant level is normal. They tell me the fix requires taking the engine out of the... www.planet-9.com I'm keeping a close eye on the coolant level. So far it has not dropped.