Procedure for 996 Coolant Change

Hi There, I have a 996 on my hands that has had Green (non-Porsche/high silicate) coolant put in it and I need to do a complete drain and flush of the system. The service manual only suggests removing the coolant drain plug and removing the vent hose, however I suspect that this will leave alot of the old coolant in the system. If anyone has some tips or tricks for getting most or all of the coolant out I'd be very grateful for the information. Also, when filling the coolant there is a step two of the process which states that a special jumper must be used (part 964.610.184.00). I have ordered this part and will use it for future coolant work on this type of car, but in lieu of waiting can anyone tell me which terminals to connect? Your help will be much appreciated! Thanks, J

That is factory fill or did the customer tell you they added the wrong coolant?

The customer had the engine out (at a different shop) for a rear main seal replacement and the shop put the green stuff in when they put the engine back in. The proper coolant for these cars is the pink low-silicate stuff from Porsche.

i know about the pink, i am just saying that it is not pink from the factory. If you want EVERYTHING out I would use this tool. To make sure everything is out drain it like normal and also disconnect the tubes from the radiator and drain them. With the system lift the back end up and then do the front end. Connect everything back up and connect the tool i have pictured above. If you are going to use a tool like that post again and I will do a write up.

I'd be interested in a write up... A

Hi there, I definitely have a tool like that so if you could do a write up it would be much appreciated! If you could cover the stages involved in filling that would be appreciated too. Thanks so much for your help! Jeremy

Draining and Filling Your gauge will look like this... *The bottom blue thing screws into the coolant reservoir. *Connect a line from your premixed coolant jug to the side without the long tube. *On the side with the long tube you leave that tube open to atmosphere and connect shop air to the fitting. 1. Drain all the coolant from the vehicle. 2. Connect any disconnected hoses and screw in drain plugs. 3. Mix your coolant and distilled water into one large jug(enough for the whole system, if you suck air you will need to start all over). 4. Connect the premix jug to the valve/gauge 5. Screw the bottom of the valve/gauge to the coolant reservoir. 6. Make sure both valves are closed... 7. Connect shop air. Air should be blowing out the open tube to atmosphere. 8. Quickly open then close the valve on the premix side to fill the line to prevent air when filling. 9. Open the valve on the side with shop air and tube to atmosphere. (jug=closed shopair=open) You are now pulling a vacuum on your entire system. You should be able to see all the rubber lines sucked in on the system and the gauge will start to move. If this does not happen you have an air leak. 10. Once the gauge is in the green, close both valves. Disconnect the shop air and let it sit for a few minutes, the gauge should stay where it is or you have a leak. You now have a full vacuum on the system and are ready to fill. 11. Fully open the valve on the coolant jug side. (jug=open shopair=closed) The gauge will drop fast and then slow once the system is filling. 12. Sit and wait for the system to fill. Watch your level of coolant in your premix jug. If you are low you can close both valves and add more. Once the level in the jug stays the same the system is full. 13. Close both valves and remove the gauge/valve from the vehicle. __________________________________________________ ________________________ THIS IS ALL PERSONAL PREFERENCE NOW __________________________________________________ ________________________ 14. Jack up the back end(mid/rear engine) of the car slightly but enough so the car can still get oil. I do this since you want the open to be the highest point to let out any air. Leave the cap off or put on cap and open valve. 15. Start up vehicle and turn heat on HIGH w/ front defrost. 16. Sit and wait. Make sure you have heat coming out of your vents. Watch the temp gauge iirc the t-stat is a 180*. Once it reached 180 wait a few more minutes to see. Coolant will be spilling out the rear from overflow. 17. Put the cap on/close the vent and test drive the vehicle. 18. Remove or add coolant to set the correct level. Disclaimer: All repairs done to vehicles should be performed by trained professionals in a proper workspace. Dispose of all waste properly. I am in no way to be held responsible if you screw something up. I am no way held responsible if i wrote something that screwed you up. I am here to help and will answer all questions to the best of my knowledge.

Thanks boss! This is a great write up. Hopefully I'll receive the jumper part today and can try this out. For the 996 the only other part is that during filling one is supposed to activate some sort of fans or pumps by pulling two relays and using the jumper part from Porsche. Once I've figured out exactly how to do that I'll post that part of the procedure to add to your excellent write up. J

Quotes source post: 4632279

I have done countless 996's and have never done that or does the service manual say to do that. If you can find something, I would be interesting to see what it says. Good luck

The service manual specifies the need to forcibly engage both secondary fans at Stage 2 (with Stage one being the initial fill when adding the fluid and topping up until short sharp revs of the engine do not pull any more fluid into the system). The service manual sections reads as follows. "8. Forcibly engage both secondary fans at Stage 2. To do this, forcibly use special tool 9235 (Relay Pliers) to pull the radiator fan relays No. 20 and No. 22 out of relay carrier 1 (on the left side in the driver's foot well). 9. Insert the jumper into relays 20 and 22. Run engine for an additional 5 minutes at 2500 RPM, revving to 5000 every 30 seconds. Then shut down engine and allow to cool to 80 C. Open coolant cover carefully and top up." Follow that by closing the butterfly bleeder valve and a final top-up if necessary. If these steps aren't really necessary it'll make things simpler for me. Let me know what you think. J

PS - Have you done any electrical diagnosis on 996s? I've opepened the thread below for another issues but no responses so far. http://forums.pelicanparts.com/showthread.php?t=471181 If you have any advice on the subject it would be very much appreciated. Thanks! J

Quotes source post: 4633612

I think that is a bunch of mumbojumbo! I have never done it and never had a come back. What service manual is that?

Official Porsche service manuals for the 996.. I'll take your experience over their questionably written instruction any day :-) Anyways, if you're interested it is on page 19-3 in the Group 1 Engine section. I already have the jumper on order so I'll let you know if it makes any difference. Since you've never had an issue I highly doubt that it'll do anything useful. Thanks again for all of your advice on the subject. I'll let you know how it goes. J

Quotes source post: 4633964

I will have to look. Thanks and good luck(you should not need it)

I believe targamaniac is correct. If a Porsche shop does this they use the the porsche diagnostic setup when the coolant is changed and it runs the fans.

I just looked in my online and paper manual. It does not say anywhere to turn on the fans.

Is the tool shown available somewhere? Thank You

Quotes source post: 4669119

that tool shown is a porsche special tool and should be able to be ordered from any dealer. There are many different types of them. Track down a tool truck(snapon, mac, or matco) and they should have something like it on the truck. Google "Cooling system refiller"

Thank you,