Fahrer

Well, I drove my car ( 2008 C2S) today for about 1.5 hours. It was hot so I brought it into my garage at the end of my drive and gave it the usual 2 minute cool down at ~1400 rpm. I shut it down, opened the car door and smelled glycol. Uh Oh.....
I went to the back of the car and found a big puddle ( 1-2 square feet) and dripping significantly/substantially from the water fuel pump area. I can't really tell where the leak is.

The coolant reservoir was very low with coolant only visible in the lower/under section. I put a pan under the car and eventually the dripping stopped. I am not sure if it ran out or the dripping stopped due to the pessure subsiding. I noticed there was a trail of coolant drops in my driveway and down the street as well so it happened on the road. Exactly when?.........I fear to guess.

Funny, I always watch the oil temp and it stayed normal. As the coolant temp is always on 175F I never noticed it today. No dash warning lights.

I made arrangements to have my car flat-bedded to the dealer for repair.

A damaged hose? A failed water pump? Not too worried about either as I have a Fidelity platinum warranty. I never did hear any weird noises and the pump looked OK just about a month ago. Also, it has just 25K miles.

I just hope my engine isn't damaged....

Macster

Not sure where you got the idea that runnng the engine at ~1400 cools it down.

It has just the opposite effect.

When I want to increase the heat of an engine to say perform a hot coolant pressure leak test I run the engine at ~1400 RPMs until the radiator fans come on then shut off the engine and let it heat soak.

A "cool down" is easy driving on the way to your destination and then once there before you turn off the engine you can let the engine idle some especially if the radiator fans or the engine compartment fan are running because the engine is hot. Often I let my Boxster idle until the fans shut off. The Turbo gets a 2 minute idle cooldown regardless as that is called for in the manual to let the turbos cool.

Anyhow, the engine isn't damaged. What likely happened is you got the engine nice and hot and this increased the coolant pressure and a weak spot leaked. Given how fast the coolant leaked out I'm guessing the coolant tank failed. They often do. The favorite spot is along the seam that runs along the bottom of the tank.

The tech will make the diagnosis though whatever the failure.

When you get the car back consider modifying your engine cool down procedure to one that actually allows the engine to cool down, shed some heat load, before you shut the engine off.

KNS

Like Macster said, just drive gently a couple of minutes before you pull into the garage (or wherever you're going).

You can also turn off the AC compressor (the snowflake button) or the AC completely a couple of minutes before you've finished your drive. When the air conditioner is running the condensers are dumping hot air right on to the radiators.

Fahrer

Actually, it does bring the oil temp down a bit faster during the two minute period and then the coolant fans turn off at the end of the two minute period so the heat soak is minimized. As we know the cooling sytem cools the oil and this brings the system to a steady state before shutdown. It may very well be the coolant tank but was just not able to see. I have tried turing off the A/C a few miles befoe shutdown but I have found that with the A/C fans running, the car seems to cool off faster.

As has been said, I will wait for the dealer to advise.

DC911S

That's about the lifespan of a coolant tank.

captainbaker

And apparently the water pump. Thankfully mine was replaced by the PO including the belt.

OP, if the engine temp was in the normal range when you shut down, you are good.

FWIW, my wifes Jag XK has the stupidest warning system. It only tells you when the coolant system is low....no coolant temp anywhere. The service advisor said the engine management will shut off the engine before damage. Thats comforting.

syzygy333

that reservoir looks like it holds a gallon of coolant. now I am off the clutch fluid windmill jousting, maybe time to get a bug up my %ss about the reservoir life span.
it could be made of metal, still have the little plastic filler tank to monitor.
hmmmmmmmmm wish I was a metal fabricator
titanium would be nifty. just sayin'
my bad- it's all of a piece. probably cost 4,000.00 to have one fabricated.
Porsche:2 Syzygy:0
game ain't over yet.....

DC911S

Well it's a weird shape and would take a pretty good fabricator to make one out of sheet aluminum. But you thnk by now sonebody would have done it.

syzygy333

I know just north of squat about these tanks, but I think it could be streamlined a tad, perhaps reducing overall volume a little, as long as the fittings were in correct relationship to each other. a fabricator's wet dream.
and if you lose the translucency of a plastic tank, can always replumb the low coolant probe to a higher point. where it is now is almost at the bottom of the tank.
my jag v12 overflow tank was black plastic AND located in a fenderwell. only monitoring was coolant temp and a low coolant probe situated high enough to make a little sense
I watch my coolant level like a hawk, pretty much every drive. if it goes, I just hope it's a small warning leak. especially since I just drained/filled with about 200.00 in Porsche antifreeze and distilled water!

semicycler

The coolant overflow tank is prone to cracking with age where it connects to the lower hose. The next common failure is the water pump bearing. Usually you have some symptoms before a wp failure but not always. Plus a WP failure doesn't always drop fluid to the ground in one big mess all at once whereas the coolant tank failure will. So without knowing more about your pre-failure symptoms I'm guessing overflow tank.

Since they will be in there anyway have the WP, overflow tank, and perhaps the thermostat replaced. It's also a good time to consider installing a third center radiator if your make/model doesn't already have it.

syzygy333

wonder about the everyday benefit of a 3rd radiator? coolant will still come up to temp as regulated by thermostat. maybe if tracking car?
otherwise, I see 3 or 4 more possible leak points and slightly increased coolant volume
am I missing something?

semicycler

Yeah, mostly track or aggressive street driving, perhaps hot weather climates too. It helps keep the oil temps from climbing too high. Not really a concern for daily or sport street driving. But if you ever considered doing it, now is the time as the cooling system will be apart - think labor savings.

syzygy333

good points semicycler. didn't think specifically how it would help keep oil temp down. that's a big plus. hmm.........
I would like to increase oil capacity without going too crazy. the 2 qt. extra sump pan is like 2k dollars. nah!
a one qt. enlargement would be nice but I don't track or push the car too much. so probably fine as is

sandwedge

What if the engine management system fails? Is there a warning for that?

Fahrer

Update - I just heard from the dealer and it is, indeed, the water pump. Well, a new pump, belt and thermostat... glad I purchased the Fidelity warranty.....only $100 bill for me.