Just saw this after I parked in garage. Just got back from an 8 mile drive. Car is 2002 996. Any input?

 

very common issue with the 996. Does your tank look yellowish? If so, then there's a good chance that the tank has a crack. Also an old cap may cause the leak too. But 1st check all your hoses if they're loose.
Its a PITA to change the tank if you don't lower the engine.

 

Just figured that out while I was looking around. Guess it's expected for 13 yr old car huh? Just want to make sure no other part involved.

 

What MkC2S said: The coolant tank most likely has a crack/split. The seam along the bottom appears to be the most common location.

The cap can leak but the signs are not quite as dramatic as a puddle of coolant under the car.

Regardless, when you replace the tank be sure you fit a new cap.

Other items in the cooling system circuit could be going bad too, so you have to give them a good check. The water pump, any coolant hoses, the radiators, the AOS, the oil/water heat exchanger are some of the biggies.

My philosophy is there are always 2 problems, unless there is just one or 3 or more.

 

Interesting thing happened this morning. I decided to drive car for several miles until it gets to normal operating temperature then parked the car and let it cool off. Coolant level was at the minimum level. I waited to see if it will leak but it did not. Drove it longer this time, coolant level stayed at minimum level. Engine is not overheating and temp gauge showing just a little past 180. Not sure what's going on. Maybe leak coming from top part of reservoir tank? Still going to replace it since it old. Any ideas?

 

Not surprising behavior.

After the tank in my Boxster let go with a huge gush of hot coolant I let the car sit overnight and the next AM filled the tank with distilled water then drove the car a couple of miles to the dealer. No sign of a leak on the drive or at the destination but the tank was clearly bad. Once off it was clear the tank had been leaking over time.

The fluid under the car -- in the pic you posted -- is a sign there's a serious leak -- any leak in the cooling system is serious -- and needs to be found and fixed.

As has been mentioned the likely problem is the coolant tank has developed a crack/split along its bottom that arises from where the mold seam is.

Under some conditions the tank will not leak or if it does leak it leaks very little. For some time I was catching a whiff of anti-freeze smell which I knew was a sign of a leak.

However, a hot pressure test can have the tank gushing coolant. It was such a test I did with my Boxster that had the tank gushing hot coolant.

Briefly, top up the coolant level -- you can use distilled water -- to the proper level, not too full but not too low either. Be sure the cap is on properly and tight.

Start the engine and let it idle while you check for any leaks. Assuming there are none then drive around the neighborhood or town until the engine and cooling system are fully up to temperature. You want to hear/feel the radiator fans coming on. Oh, and have the A/C off during this "test".

Back home in the driveway raise the RPMs to say 1000 or a bit more. Hold until you hear or feel or a helper signals the radiator fans are running. Shut off the engine.

Wait.

As the heat load of the engine raises the coolant temperature and pressure that coolant tank -- or any other leak -- will if not gush coolant will manifest leak sign.

I do not think you need to do a hot test as the puddle of fluid under the car is clear sign there's a leak. An inspection of the various cooling system items will I'm sure identity the source of the leak.

 

After the puddles appeared under the car did you add fluid to bring the level up? Old coolant tanks can develop a stain line that can look very much like the tank is full when in fact the level is way down.

Sometimes one can jiggle/jostle the car enough to see the fluid in the tank move and then know the level. At other times if the level is down one has to remove the cap and the screen if there is one present and actually peer down into the tank to check the level.

 

Just ordered the reservoir for my car from Sunset Porsche for $127.00 . Not as bad as I thought. Looks like it's going to be a busy weekend but well worth it

 

Finally got it done. I did lower engine about 4 inches or so.

 

So did the new reservoir cure the leak?????????????????????????????????.. was there a split in the old one????????????

 

Leak is gone. 👍🏻. There was a crack that ran vertical in the back



Glad it's done, PIA but worth it for me. New cap and reservoir cost $154.00.