MattAu

I recently saw a coolant drain and fill on a 996 Turbo. I was alarmed and puzzled by the amount that was drained from the drain plug (seems like a lot more than 10 litre) than the amount that was put back in (around 10 litre). It was refilled using a SnapOn version of the UView Airlift.

Since the 2005 and 2006 cars are hitting the 4-5 yrs mark, have anyone done a coolant flush on a 997 yet? If so, can you just drain from the drain plug or do you have to remove the underbody panels and disconnect some of the hoses as well to properly drain all the old coolant out? And if you just drain from the drain plug, did you get most of the 32 litre out according to the specs in the owner's manual? And more importantly, did you put close to what you drained out back into the system?

Anyone has a link to a DIY guide?

jumper5836

The coolant is a lifetime thing. So no flush should be necessary.

NA011

I pulled this from somewhere. Renntech.org? I usually keep the ulr link in the saved document but I didn't this time.

Macster

The 997 I'm not sure about but you can drain some coolant from the engine at the coolant drain plug under the engine -- I don't have a location for the 997 engine so you'll need a *reliable* drawing or picture to know where this is so you don't loosen the wrong thing -- and drain the coolant into a clean drain pan.

Measure the amount of coolant and then add back into the engine coolant tank the same amount of fluid consisting of new anti-freeze of the proper type and distilled water.

While this doesn't remove all the coolant it removes a good portion of it and the new anti-freeze will help replenish the coolant's anti-corrosion and other function additive package. If you do this every so often -- yearly? -- the coolant remains fresher than it would be otherwise though not as fresh at least initially if a full drain and subsequent refill would have it.

A full drain is more work and more trouble to refill the cooling system properly.

You might investigate one of the coolant vacuum/refill systems. The dealerships use these. The coolant is drained. The vacuum system is hooked up to the coolant tank and a vacuum is pulled on the engine cooling system. Enough I've been told to collapse the rubber coolant hoses.

The vacuum valve is closed off and the valve to a tank of premixed coolant is opened. This tank is vented to atmosphere.

The pressure difference has the contents of the tank flowing into the car's cooling system and the cooling system ends up filled completely with fresh coolant with no air pockets.

My Boxster's cooling system was refilled this way at the Wichita KS Porsche dealer after radiator replace (after I broke it hitting some road debris late at night) and I was at first suspicious of the system being properly refilled.

I drove the car around in the July heat of mid-Kansas and for several hours and the coolant level never dropped and the car's cooling system and AC system worked just fine. Stayed working just fine for thousands and thousands of miles afterwards too. (Till unrelated to the radiator work the water pump finally (at 172K miles) required replacing. This done at another dealership and the same technique used and again the coolant refill done right.)

I do not like the run the engine until hot add coolant repeat method.

BTW, while Porsche claims the coolant is lifetime one doesn't know what lifetime means. I think a 4 - 6 year drain/refill if done properly a good thing to do for the engine. There are alot of very thin walled radiators and oil/water heat exchanges and heater core in the car. The block won't get eaten through but you want to ensure those thin walled radiators and such retain as much wall thickness as possible and a periodic drain/refill with fresh coolant the ony thing you can do to ensure this.

Now before I got around to changing the fluid the radiator damage and subsequent refill saw this done. Then at 172K miles the fluid again replaced when the water pump replaced.

And just this week the coolant again removed and replaced to fix a cracked coolant tank (at 231K miles).

Sincerely,

Macster.

Steen Jensen

I did this a few weeks ago , though not intentionally. One of the main cooling hoses popped off resulting in the cooling system spilling its guts in short order. I put in 8 litres of distilled water and 8 litres of antifreeze. By the way , you can buy the pink stuff cheaper at your local VW dealer.
This system bleeds very slowly so you will be topping it up about 5 or 6 times. There is a bleed valve on the overflow resevoir.

Edgy01

As I told you two days ago, the system capacity is 8.45 gallons (32 liters). These are complex, convoluted cooling systems. Draining them is not a simple thing of putting one end of the car lower than the other and letting gravity do its thing over time. I don't personally believe in "lifetime" coolant either, but there are opportunities to change your coolant that don't require a dedicated session at the shop. For example, if you need a new water pump that is a good time to replace all the coolant. If you have to replace the coolant overflow tank--replace the coolant. Here's where the stuff comes out at the rear of the engine.

Clifton

Much to Macster's point, it all depends what the definition of "lifetime" means to Porsche.

On my 2003 M3 (June build), BMW required a coolant flush every 4 years. My buddy with a 2004 (Aug build) took his in at the 4 year mark and they told him they don't flush cooling systems anymore. They stated that the coolant is a "lifetime" fluid. Oddly enough, the coolant is the same in both cars. Nothing magical about the coolant, BMW simply wanted to delete another item from their "free maintenance" program.

While in theory the "pink" antifreeze fluids in our Porsches are designed for longer run cycles, I think their is wisdom in flushing any cooling system at reasonable intervals (eg. 4-6 years for normal use, 1-2 years for track use).

"Lifetime" fluid is intend for the use, throw away and buy another mentally. Any mechanical part that is expected to stay in service, needs to be maintained as such.

NA011

MattAu

This is a web site that has the 996 Shop Manual: http://cannell.co.uk/Manuals.htm

Go to Porsche 996
Download pdf Group 1 Engine From 15.pdf
I think the file size is 94+MB

Pavelpu27

Hi all, I have replaced the collant on my 2005 997 C2S with my mechanic just now. Since I had to replace the leaking waterpump I have also exchanged the serpentine belt and the coolant. Actually, we have taken some 12 liters of the original coolant out on the first attempt draining it from the back of the engine. We flushed the system with distilled water and then had it drained not only from the back of the engine but also from the two pipes behind the fuel tank on both sides at the bottom of the car. We managed to take out some some 20 liters of fluid, which is almost all of it. Then we put in 12 liters of VW (actually Skoda) pink antifreeze fluid and approx. 7 liters of destilled water. The system seemed full, but we knew there should be space for some 3-5 more liters. After driving 10 miles the system announced low coolant level and after it cooled down I was able to put there remaing 4 more liters. The replacement took approx. 2 hrs and it can be DIY job, but I am lucky to have a friend who is a garage owner with all the tools needed.

Dan GSR

Holy bump