Coolant leak, light flashing, fans running!

[nola911]

Ok guys, if you have any advice or suggestions let them fly. It started 2 months ago with a coolant leak behind the right rear tire. The tank never drained past the full level. I figured it was overfilled and some came out the overflow (if there is such a thing). There was no moisture in the trunk and no puddles under the carpet. The tank itself is not damaged.

Now, it has been 2 months and maybe 100 miles since then without incident and absolutely no puddles in the garage... until this weekend. The whole tank emptied out similar to before behind the rear tire. Today, I put two cups of water in it expecting it to rush out a bad hose, but it did not leak. The water was not even half full in the tank. I started the car and let it sit for 15 minutes. It ran fine for a while, then the tank started filling with coolant from somewhere else in the system. As it did this, it overflowed itself and started leaking and the thermostat started to near the third temp line (over 180).

I turned it off and summoned the Bently guide and 986 forum search for ideas. Having struck out, I went back to it. Now, with the tank miraculously at the typical fill level, I restarted the car and took it out of the garage thinking it might be the hot single car garage that was making it hot. I drove around the block. As soon as I made the first turn, the red light on the right of the temp started flashing and the fans started running. It ran a little hotter than usual (near the third line), but not getting near the top temp. By the time I made it back home, the fan was running harder.

Am I correct in asuming the light flashes if it is too hot OR if the radiator has no fluids?

I read of leaves or debris sometimes block radiator flow, but my garage queen has no such debris.

Any help is deeply appreciated. I want to avoid the 300 dollar tow fee to porsche if it is something minor that I (or local german repair shop) can handle.

[djomlas]

open the trunk and see if you have a blue cap that ends in 01, if you have one that ends in 00 theres your problem.
happened to me, emptied out the whole tank behind the tire while driving
btw, te car is only around $17

[nola911]

DJ, Cap #44701

Oh well, I thought I had it! Thanks anyway

[djomlas]

damn, although a good thing that you have 01 cap, too bad it wasnt a cheap $17 fix.
lets just wait what others say, hopefully someone else will have some insight

[nola911]

Ok, the repair shop (not Porsche) says it is a bad thermostat. I do not know enough about the cooling system to make a call, but the guy at the porsche parts desk seems to think otherwise. He cannot say what he thinks it is, but he says that thermostat wont go bad and if it does, it will not have my symptoms.

Anyone?

[MNBoxster]

Hi,

It could very well be a bad 'T'stat, or a leaking Coolant Reservoir, or bad Spring Clamps, or even a leaking Hose.

You'll need to do some investigating to zero-in on the cause.

A leaking Coolant Reservoir won't necessarily leak all the time. Small cracks may open up (expand) when the system is Hot and re-seal (contract) when the system is Cool.

Same thing with a failing Spring Clamp. System Hot (pressurized) the Clamp may allow Fluid/Steam to escape, while Cool (unpressurized), it seals OK. The same goes for leaky Hose(s).

The 'T'stat can be removed and checked by submurging it in Boiling Water. Check that it opens. For accuracy, use a Thermometer and see what temperature it opens at. But, for the 'T'stat, since you need to replace the Gasket, etc. when removing it for a check, on a car with some mileage, it's best to simply replace it altogether.

You can get a System Pressurizer: http://www.tooldiscounter.com/ItemDisplay.cfm?lookup=KDT3700 and pressurize the System Cold. Then you can check around the system while it is pressurized to look for Leaks. The Pressure Tester @ $90+ (possibly cheaper on eBay, Craiglist, etc.) may seem expensive at first, but it will allow you to do most Cooling System R&R yourself, eliminating expensive Shop Time - a worthwhile investment which you can also use on all your other cars as well. Hope this helps...

Happy Motoring!... Jim'99

[dkriebel]

I had leaking problem that turned into overheating problem in a 03S. porsche towed it and tested everything and finally said it was the coolng system cap not allowing system to pressurize properly. Air in system, water pump cavitating? No problems since thay gave me a new cap, 10 months.

[nola911]

Update:

I ordered the thermostat and it will be in tommorow. The shop pressure tested the coolant system and they said everything was tight. Both porsche and this indy shop agree that air could have gotten in the system, and that the thermostat is the first thing to look at. For my own peace of mind, I am replacing the tank cap and the seals while it is being ripped apart.

I was able to get the coolant to leak while I had the carpet pulled off the trunk and it seemed the tank was sealed because none entered the trunk.

Mere trivia: for those who have never bought coolant from porsche, it costs 55 dollars a gallon

[nola911]

I forgot to add, the car is a 2000 model.

Thank you all very much for the help

[djomlas]

there is cheaper coolant to get, go look at the DIY section , i flushed the system, and the guide is there, as well as what coolant to use that is also approved, and will save you a LOT of money