Raining in my boot

I think this is yet another failed expansion cap but just wanted to run it by everyone in case I should be more worried.
My TF has been quietly loosing a little coolant, nothing wrong with the oil, no increase in the oil level, coolant is nice and clear but a few days ago I noticed some condensation on the underside of the bootlid. I wiped it off and then checked again this morning, after leaving the car running on the drive to defrost and the condensation was back. After driving to work, it had got a fair bit worse, even as far as dripping down onto my laptop bag in the boot.
Am I right thinking it's probably the expansion cap venting too early and the steam condensing on the cold bootlid? Or is it coming from somewhere more serious?

The easy way to check is to wrap some kitchen roll around the expansion tank neck, if it goes pink(or other appropriate colour, you've got your answer.
Get a new cap anyway as they're cheap, but get a 'proper' one from the likes of Mike Satur.

See this thread

The one that's failed is a proper one from Mike Satur but I've ordered another one anyway.

andy1970h wrote: The one that's failed is a proper one from Mike Satur but I've ordered another one anyway.

Have you confirmed it with the kitchen paper?:shrug:

David Aiketgate wrote: The easy way to check is to wrap some kitchen roll around the expansion tank neck, if it goes pink(or other appropriate colour, you've got your answer.
Get a new cap anyway as they're cheap, but get a 'proper' one from the likes of Mike Satur.

That is a top tip :broon: :broon: :broon:

If it is actually dripping in the boot itself I would think you have a leak elsewhere, possibly the rear light seal, letting water into the boot. When the engine warms up the damp boot lining will warm up and the water will evaporate and condense on the cooler boot lid and drip back down.

I think the boot climate theory is spot on. The exhaust heat will boil it out, it will condense on the cold boot lid, drip down and be ready to cycle again. I washed my boot carpet when I got the car and vacumned it out with a wet n dry Vax and its been fine since so maybe the boot is leaking as well. This was a well known "they all do that sir" in the early days of the MGF . i do remember seeing fixes posted so you will find this archived, with luck on here.
There are several coolant pipes on an MGF but some crop up regularly as leak culprits, again the archives have a lot of info.