well they say things come in threes.....
A couple months ago I took something in my tire during my drive to work with the low air pressure warning coming on as soon as I pulled into my parking space.
One month ago, the engine began whining,especially when cold or turning the wheel. Power steering fluid was a little low (at the min line when cold), so I topped it off and seems okay now
Thursday, after a non eventful drive into work, I start the car to go home and the low coolant level warning immediately comes on. Within 15 secs, the temp gauge claims its already up to 250F, turn the car off. Put about a pint or so of distilled water in, to bring the arrow into the middle of the reservoir gauge. Car starts fine , temperature slowly climbs to 201F after about a minute. Drive home (mostly freeway 10 miles) and towards the end noticed the temp would slowly rise to 225-230F for about 30 sec or so, then quickly return to 201F. After a few minutes at 201F it would repeat the cycle of a brief spike.. Friday morning, needed to add a little coolant, it was about half way between the middle and (-) edge. Friday evening did the same thing with the temperature cycling, although it did spike to 250F as I pulled into my driveway.
Does this sound like a thermostat problem? And while I can smell antifreeze when I turn the engine off, I can't spot a leak- but obviously I am losing some.
What are the normal water and oil temps?

 

my water temps stay rock solid at 194, oil will climb as high as 220 in comfort mode.

how strong is the coolant smell? have you had the thermostat housing changed?

 

Coolant smell really isn't too strong, and as far as I know, the thermostat has not been replaced. Approaching 95000 miles.

 

seeing any white smoke on start up?
might still want to take a bore scope and look to see if you have the updated thermostat housing and if there is any coolant in the V

 

No smoke that I've noticed. Updated thermostat housing? Was there a recall? I guess I'll have to look into that!

 

You are losing coolant That's a problem - full stop. It is either being eaten (superbad), leaking (could be bad) or boiling off through the cap (easy fix.) Figure out where the coolant is going first. Once you address that, you will most likely also address the getting hot problem. Your cooling system has an opening somewhere to the atmosphere, which is allowing the pressure to decrease, thereby lowering the boiling point of the coolant. Coolant boils (or leaks) out, air comes in, heat goes up. The easiest thing to do is to take the pressure cap to a shop and have it pressure tested. That could be the entire ballgame right there and a new cap is only like $50. If the cap is good, start looking at all the hoses and hard parts for leaks. Inspect the thermostat housing and water pump housing - two very common culprits.

Also, do not use regular coolant. Use the Porsche approved coolant that is friendly to magnesium and aluminum parts. The plane-Jane coolant is no bueno.

 

Took the car out today for about a 4 mile ride to HD, it went up to 201F and stayed there on the trip out, but coming home with an already warm car, after about 2 miles the temp started rising when oil temp hit about 170F.

Where's the location of the water pump, presumably front and center? I think I did notice some seepage on the left lower side and then later when I moved the car forward a spot on the driveway which corresponded to about the same place. I'll attached a pic....

Noticed some drops of moisture on the flat pan above

 

top center, just under the intake. it's pretty easy to get to and service.

 

Pull the belly-pan to get a good view of what's going on. That pan hides a lot of ills.

 

Try turning AC off just to see. I found mines going to 215-225 if stopped in traffic for a while with AC on. if i turn off it'll cool down and stay at 194 also if on freeway or over 40mph its always 194. if you're on the freeway and its that hot then sounds like thermostat or pump. After a drive feel the radiator or hoses and see if hot. if coming from overflow it seems coolant comes out by back of drivers door and no where near the hood.

 

Have you had the coolant flushed or changed recently? Sounds like you have a leak and/or air in the system. What you may be seeing is the air pocket (containing very hot steam) passing the sensor creating the high temp reading, while the coolant itself may not yet be that hot. Depends upon how much coolant you have lost.

Hopefully its an easy fix such as the coolant cap.

 

Thanks for all the comments. I dropped it off at the dealer last week (mainly because I didn't really have the time and had a big credit balance on my Amex card from a canceled cruise).
They replaced the coolant vent tube (bleed line). Would have been a cheap fix had I done it myself. They also spotted maybe my next DIY (hopefully) and mentioned the one of the valve covers was starting to leak.