Could be the coolant expansion tank. Also here is some info on the coolant Ts. Read for a few pages.
https://rennlist.com/forums/porsche-...es-a-z-30.html

 

So you're saying there's a possibility coolant leaked from another vehicle and somehow went through the hood and into your engine compartment?

Have you bothered to remove the pressure tank cap and check the level of the coolant? Have you then gone back to check if the coolant level has dropped?
Or does it seem like a better plan to have your mechanic take apart the top of your engine and look for a leak that may not even exist?

 

Just a possibility, albeit slim and doubtful that the original owner said he has had happen in the past but it leaked into the defroster vents. I have checked the coolant level, it is full, but only having the car for a day I haven't been able to watch the level more than that. I do not think it is a good idea to take things apart when it isn't obvious what it is, but I also know if there is a smell there is coolant leaking somewhere. Maybe the best thing to do is drive it a bit and see if it subsides and keep a watch on the coolant level. The smell is fairly strong though at times that is why I'm concerned. Unfortunately there is just no way to know if one of those little hoses or fittings under the intake is the issue without taking the intake off I don't think.

 

If you're smelling it inside the car or outside the car, something is wrong. If you pop the hood and get a "faint wiff" with your head right over a fully warmed up engine, go back and read post 81. Next time you notice it, remove the little access cover and sniff around the pressure tank cap; the smell will probably be strongest in that area. That cap must vent and the vapor will smell. If it doesn't vent excess pressure, the cooling system will destroy itself. Real Porsche coolant also seems to have a stronger odor than the common stuff I use in my other vehicles.
Personally, I would get the coolant so that it's just barely covering the top of the yellow "full" disk on level ground while the engine is stone cold. Then check it once a week while the engine is cold. You'll know within a few weeks if you have an actual leak.

 

Yeah I smell it outside the car. Don't get me wrong, I would love for the vent to be the issue, I just don't think it is. Odd though that the original owner said he never smelled anything, I believe him so that is why I was hoping maybe something just leaked down on it from the car above it but that is a very slim chance like I said. I'll watch the coolant over the weekend and see what happens, thanks.

 

Interesting, today there is no smell from the car. It has been sitting with a hot engine in my enclosed garage after running errands this morning and I go smell it every 10 minutes or so and nothing, not even when I pop the hood. Previously you could smell it in the open air outside walking around the car, and enclosed in the garage it was prominent when I first entered the garage. It makes zero sense to me unless there was something that dripped somewhere and finally burned off like the previous owner said had happened to him from a car leaking above his on a transport, or maybe an intermittent leak from water pump maybe? I'll keep a close eye and nose on it.

 

I think it is the type of coolant used by these vehicles. My wife has had a couple of VWs, '13 GTI and '17 Golf R that use the same coolant as my CTT did. The GTI would smell on occasion. I took it to the dealer under warranty knowing water pumps can fail on these. Perfect bill of health. Put another 50k on it before trading for the new one. The new one smells sometimes too, so did my Cayenne, even though all of them could easily pass pressure tests. There seems to be a small amount of evaporative loss in these systems over time. It is a good practice to monitor your coolant level and keep it topped up.

I would do what has been suggested and monitor it. Have the system pressure tested. My bet is that there is nothing to worry about.

 

I'm not sure about this - both my 997s use Porsche pink coolant and there is never a coolant smell from either of them unless the water pump is physically leaking. I think the Cayennes have so many coolant fittings and pipes that very small leaks devlop that result in the initial smell, but they're so small initially that it evaporates before leaving any real evidence until it gets bad enough.

If a car in a transporter were leaking onto a lower car enough to create a smell, there would be visible evidence of it, unless it's magic coolant like the JFK magic bullet that actually dripped at the exact time the driver accelerated and got it to drip right through the front gill into the engine bay.

I'm pretty sure you have a small leak somewhere and it may get even smaller when the termperatures rise in the next week.

 

Yeah, I'm definitely going to watch it, drove it again a few times today and still smell free so that's good. I will tell you I'm having a blast with this CTT, wow what a difference from my base Cayenne. My wife is making fun of me b/c I want to drive it more than my 911TT right now hahahaha.