firthy247

Hi all new to the forum but I still cannot find exactly what I require within the search feature to help me out so here goes. (Be gentle with me!)

I have a 996tt x50 and have just changed all rads and air conditioning condensers. I whipped off the rads draining the coolant into a bucket.

I have now refitted everything, it was a lot simpler than I thought it would be, but I have a few questions

1. Just with taking off the rads have I drained the full system. If I haven't what is the procedure to complete this as I want in fresh coolant

2. I am a little bit worried now about putting the coolant back in correctly. Is there a procedure I should be following
I have read somewhere I need a special tool, is that correct?

3. How much coolant and how much distilled water do I need to totally refill

Thanks very much for taking the time to read this post. Hopefully someone will be able to steer me in the right direction.

Kind regards,

Neil

Macster

All the coolant refills of my cars has taken place at a dealer which uses a nice vacuum pump system to draw a vacuum in the cooling system to the point the rubber hoses collapse. The vacuum line valve is closed and the valve to a tank of fresh coolant (anti-freeze mixed in proper ratio with distilled water) is opened and the pressure difference (this tank is open to atmospheric pressure) has the coolant run into the cooling system.

Since it is probably a bit of an effort to get the car to a dealer my advice is to buy a mityvac or Snap-On or some other brand of vacuum pump coolant refill system (how simple or feature loaded (and expensive) you want to go is up to you) and use it to refill your car's cooling system.

There's a fill the tank and then start the engine and run the engine at an elevated idle speed until the coolant gets hot and the t-stat opens and the coolant makes its way further into the hoses and spaces beyond the t-stat and repeat this process over and over again until (one hopes) the cooling system is full and with no air pockets. What a horrible procedure. But some have used it -- at least with other model Porsches but I don't know if anyone's done this with Turbo -- and have had success with it.

Let's see the amount of coolant...28 liters of coolant for the manual, 29 liters for the Tip. You want to mix the coolant in a 50 50 ratio so you need 3.69 gallons of anti-freeze (if my conversion from liters to gallons is right) and the rest distilled water. (You can find distilled water at the local grocery store. Be sure you grab distilled water and not just filtered drinking water or tonic water!)

Wait a minute. I just checked my references and the Turbo's cooling system requires a connection to a PST2 to properly refill.

Here's what I read: Connect the PST2 and switch on the ignition. Select menu itme "Special function" in the "Vehicle type" menu. Press the [can't make out the key symbol] key to change to the 'Control units' menu. Select menu item "Cooling system" in the "Control units" menu and press the >> key. Note: The following message appears on the screen: Start Function with F8. Press the F8 key and follow the further instructions of the PST2.

After coming upon above even with a vacuum pump based coolant refill system the Turbo's cooling system may not refill properly without the PST2. Nothing I have suggests just what this PST2 contributes to the coolant refilling process.

Sincerely,

Macster.

firthy247

Oh dear. I think I may now have bitten off more than I can chew. Sounds horrendous.

Neil

jpflip

No at all difficult.
I never went to a dealer and never will!
Simply raise the back of the car or park it in a slope facing down. Fill to the max line. Start the car with the valve open on the black cap on the expansion tank. You will see there is a metal clip that you can pull up. Drive like this for a while, keep an eye on engine temp and fill it until there is no more liquid needed. That's it....

See the way Renntech member's are doing the bleeding.... As per Loren (Renntech master moderator and long time Porsche mechanic)


"Fill the coolant tank with existing/new (porsche recommended) coolant to the max level and close the coolant tank lid. Then, to quote Loren, "Lift the bleed valve."

"Start the engine and allow it to get to full operating temperature (I also ran the air conditioning to force circulation). The coolant warning light will likely start to flash. Shut the engine off and WAIT until the engine and coolant has cooled enough to remove the coolant tank cap. Then add coolant to the tank and repeat the process. You made need to do this 2-3 times. When the coolant level fails to fall then the system is bled and you can close the bleeder valve."

About bleeding the coolant system.
Close the bleeder value after about 40 minutes (total) of good driving. You shouldn't ride with it open for more than this (my Porsche tech told me this).
You MUST wait for the coolant to cool between your 2-3 tries, else you won't be filling the tank completely (coolant contracts as it cools). I've had to wait for over 3 hours to cool. If you try before this then the coolant will spill off when you open the cap.
You may get a coolant light even with the bleeder valve closed after a few days. This is ok and doesn't mean you cracked your tank or something again. Basically there was some air trapped and the car "burped" it into the coolant reservoir, triggering off the coolant light. Wait for 4 hours for the car to cool and then top off with coolant+water (replacing a lot) or just water (replacing just a little).
If even after 3-4 top offs/"burps" you need to keep adding coolant, have it checked for other leaks in the coolant system.
In the end, once you've done it, please pat yourself on the back !! Great job !! Even my service tech. at the local dealership said its not a simple job. Its worth doing it on your own if you suspect you're losing coolant. "

firthy247

Brilliant!!! If it's good enough for Loren then it's certainly good enough for me.

Thanks you have made my day.

Regards

Neil

MK19

Short of pulling the radiators.......how do we drain the max amonut of coolant?

Also; while McM sites the system capacity, we ptretty much know that on a flush and refill we don't get it completely drained so we won't need the full capacity of 50/50 coolant.......what is the experience? How much Porsche collant do I need to buy if I'm not going to break the system down, but just do a drain/flush/refill??

Last: is distilled H2O really needed??

Thanks,
MK19

Macster

Supposedly if you open all the drains, follow the factory manual drain instructions, all the fluid will drain out save for what fluid film remains adhering to the coolant system walls, hoses, etc.

If you want to know how much exactly to put back in the car, catch what fluid you drain out and measure it and then figure out how much antifreeze you need and buy only that amount. Mix it with the appropriate amount of water and then use this mixture to refill the system. IOWs, replace only what you drain out of the system.

As for distilled water, that is my info. Some of course many in fact who do their own coolant fluid service do not use distilled water.

My thinking is why risk using tap water? Distilled water is probably the least expensive fluid one puts in his Turbo. $3 or so is not going to break the bank.

Sincerely,

Macster.

Macster

I simply do not like running an engine with air pockets in its cooling system passages. I am concerned about the possibility of localized overheating and the risk this poses to mainly head gaskets and heads (warping or cracking them).

The technique posted is a technique available for those without access to the proper cooling system refilling system. But if you are comfortable using it... Have at it.

Sincerely,

Macster.

tbarcelo

Amazon (and others) sell a tool made by UView called the airlift. It works like a charm to refill the coolant system. Costs about $100. I posted about the experience either here out on 6speed.

MK19

Besodes to drain/drain under the rear of the engine.......are there other drain points?
MK19

996TWINS

Bought from Amazon today. Thank you for the info.

adam_

I'll never use anything other than distilled water.

Kevinmacd

Thats the Porsche spec distilled water and coolant!

Macster

My info says this: Unscrew cap on coolant expansion tank.
Undo coolant drain plugs on right and left and drain the coolant. Equip drain plugs with new seals. Tightening torque is 10 Nm (7.5ftlbs) to 15 Nm (11.0 ftlbs).

There's a line drawing that shows the location of one of the drain plugs but the drawing is very poor quality. Let me see if I have a pic of my Turbo's coolant drain plugs...

Here's one. Not the best. If I'm not mistaken the coolant pipe is in the top center of the pic. The drain plug is that light colored round well plug in the coolant pipe. (The pipe is dark from cosmoline.) You can just see the other coolant pipe at the left center margin of the pic.



Sincerely,

Macster.

MK19

Thanks all..........appreciate all the info, experience. Yep, those are the only 2 drain plugs I know of, but if I recall, I'll only get about 1 to 1.5 Gallons from those drains. But it has been a while. MK19