A Lot of condensation isn't mormal. Suspect a bad cap, a poor Bleed Valve seal, a bad hose connection or a cracked coolant tank.

It's OK to top up occaisionally with water (distilled water is best to prevent introducing minerals to the system).

But, each time you do this, you dilute the coolant mix. Porsche specifies either a 50/50 mix of anti-freeze/distilled water, or a 60/40 mix. You don't really want to be <35% anti-freeze or you both increase the corrosion potential and reduce the lubricating properties of the mix.

Over time, topping up with even a little bit of distilled water on a semi-regular basis adds up. You can buy a cheap Hydrometer at most any auto parts store for about $5. This is the little 'baster' which has the little floating balls in it. It tests the specific gravity of the coolant mix and can tell you what your actual mix % are.

The coolant should really be changed every 5 yrs. or so, despite claims from Porsche that it's a lifetime fluid - it isn't.

Use the search function here to find out what brands are, and are not, compatible. There's lots of good info.
:cheers:

Just a quick update:

I talked to the Porsche dealer today, and they said they couldn't find anything obvious wrong with the car. The coolant tank was fine, all the hoses where fine, and that the problem could be only one of two things. One it that the instrument cluster was showing a bad reading and that the complete coolant drain was a weird occurrence.

The second thing it could be, is the water pump. The water pump drains out of the coolant overflow above the right rear tire (where I saw the coolant come out), and it would cause the overheating at low speeds, and not high speeds that I have been seeing. This explanation fits all the symptoms of my problem.

Here's the problem. If they pull the water pump out and nothing is wrong, I get stuck with the bill. If something is wrong then I don't have to pay anything except the deductible.
Has anyone replaced a water pump, what did it cost?
What is the likely hood of it being the water pump?

Thanks Everyone! :cheers:

I replaced the water pump, got it from ebay for $100 and my mechanic replaced it for $160. Its very simple, not too much work involved.

I had the same problem, my water would drain out little by little, it would take about 1 week and a half and then the blinking light would turn on and tempereture started to raise.

Waterpumps do fail, fact of life. A '99 means the pump is now 8-9 years old. At that age, it's not unusual regardless of mileage to have it fail.

It's a pretty easy DIY. I personally would not pay to have it done. The pump runs about $300 (cheaper on eBay), not sure if there's a rebuild kit for one, but if so, this is also an option. A rebuild consists of replacing everything but the actual casting. Seal, Bearing, Shaft, Impeller are all new. Usually the shaft needs to be pressed out and the new pressed in - I've had NAPA machine shops do this work for me in the past for under $50 with good results. You'd also need a new gasket - $8 which has to be cut because it is also the gasket for the Oil pump - an easy modification. Then you'd need 2 gal. of coolant and 2 gal. of distilled water - say $30 max. If I were going to that trouble, on a '99, I'd also change out the 'T'stat - another $15 incl. gasket.

That's what I have been reading. I think I will just tell them to check the water pump. I would DIY except with the warranty, it isn't worth $300 out of my pocket, when there is almost a 90%+ chance it is the water pump, so it will be covered.
Thanks for all the help, and I'll let everyone know what happens. :cheers:

^ My earlier post was way off.

I picked the car up today with some major trouble. After waiting for a half hour they come in a tell me that they didn't find anything wrong with the car, but they did change the spark plugs (without my consent), use half a tank of gas, and put about 50 miles on the car. Oh, and they also gave me a bill for $640. $450 in labor, $140 for spark plugs, and $50 in tax. For all I know they didn't do anything.

I didn't want to get into it in at the dealer, but this is the second time I have taken the car in with a problem, and left without any repair or explanation, just with less money. I am into this for $760. The car once again runs fine, but I'll give it about a month (again) before something else happens.
What do you guys think?

I am thinking of writing to Porsche North America, the dealership owner, and the Better Business Bureau. If they had done something I would have gladly paid, but when they didn't do anything except, keep the car a week, be rude to me, and then charge me, it is all just upsetting.

What??? Amazing that this is even possible, fortunately I have never been put in this situation. If I got my car back with a bunch of unauthorized repairs I would have had a fit in the dealership, let alone waiting a week for a spark plug change! I'm not sure where you are located, hopefully you have another dealership nearby to take your car to (I have 4 or 5 Porsche dealerships within 30 miles of me in the D.C. area). My suggestion would be to make an appointment with the service and general manager and knock out why this happened and what they're going to do about it.

I would DEFINTELY pursue this. YOU GOT RIPPED OFF!!

You go in for a coolant leak for which you had actual evidence and you end up with new plugs and a $640 bill..??

You didn't make the mistake of saying something like "Just fix it..." did you..??

You need to be very specific with a Dealer and tell them exactly what you want done and to call you if anything else pops up before proceeding and that you want the old parts back (proof that they actually did the work they say they did).

They did not call me at anytime. I called them to get updates everyday because they weren't calling. The mentioned they would look at the spark plugs, but never said anything about replacing them for $140. I never said just fix it.
The biggest problem I have is that I took the car in last month with a coolant issue, and I left with no repairs and it was $120. This time was the same thing, I have a problem they didn't fix it, and I left with a $640 bill.
They claim the $450 in labor was for testing, except as far as I can see they didn't do anything except refill the coolant, and rip me off.
I am going to write the dealership owner, then file a complaint with the Better Business Bureau.
So we'll see what happens.