Hi all,

I wanted to share a process which allowed me to quickly replace 5.5 gallons of coolant out of a total of 6.
For the past couple of weeks I have been trying to find a procedure, but didn't really find anything specific to the 996TT.
While some people seem to disconnect and drain every hose they can get their hands on, this one is really quick and largely depends on having a good compressor.
See picture 1 to understand the 996TT cooling system and where the system will be drained (courtesy of another 6Speed member)
Process :
1] Remove the coolant reservoir cap and release the drain plug(s) at the bottom of the engine (picture 2 – courtesy of another member). I removed the driver side first, let it drain. Tighten it (10 to 15 Nm), same process on the passenger side. Total amount of coolant collected from the engine : 2 gallons and 1 quart.
2] Now make your way underneath the car (mine was on jacks) and remove the under body protective panel the most toward the rear (basically just in front of the transmission). On the driver side, just before the tranny, you want to look for the location where the rubber coolant return hose is connected to a solid metal pipe by way of a clamp (see picture 3).
3] Put a bucket underneath the connection point, release the clamp (I used one of my MV Agusta specialty pliers for that – this is where hobbies meet J) and undo the hose. You will collect about half a gallon of coolant.
4] Now comes the interesting part. You will use that same drainage point to collect nearly all the coolant that’s left in the car (radiators, etc…) by applying air pressure from a compressor. Since I was all by myself doing this procedure and wanted to see what was going on at different locations, I pushed the rubber hose into a 2 inch diameter pipe which was a left over from a pool project and ran that pipe into a large volume container (see pictures 4 and 5).

 

5] Unhook the vent hose from the coolant reservoir and gently start pressuring it with your air compressor. Another 2.5 gallons will make its way out of the system (Pictures 6 and 7). Picture 8 shows the status so far : 2 gallons 1 quart from draining the engine, half a gallon after uncoupling the return hose and about 2.5 gallons from subsequently pressurizing the system
6] Now it’s time to connect all the hoses again and fill up the system. I did an intermediate step and filled the system with distilled water to give it another rinse. This also allowed me to get to know my new UView 550000 Airlift Cooling System Leak Checker and Airlock Purge Tool Kit (picture 9). I won’t go into a lot of detail since there are several references on this tool, but I can highly recommend it. The key is to have a strong compressor and run the tool’s gauge all the way up to 27 PSI before shutting it off.
I was also fortunate to have a bucket which held 6 gallons, which is what you will need for this process.
7] Drain the system again and as a last step fill it with the real thing. My process allowed me to replace about 5.5 gallons, which is nearly all of the coolant (before bleeding it – don’t know whether I will need to add more). Good enough for me !
The end result is nice pink G12 coolant (picture 10).
I hope this helps somebody.

 

This also concludes my 30K maintenance :


- oil change
- transmission & differential oil change
- brake fluid change
- spark plugs & 997 coils
- fuel filter
- re-oil air filter & clean MAF
- new water pump (preventative - there was nothing wrong with the old one)
- coolant change


This was a nice and rewarding project !

 

Nice work would have to be gentle with air psi.

 

Very good job Yves!!! Thanks for taking the time to take those pictures and write the text!!!

 

Excellent tips - Thanks!

 

I vote Sticky somewhere!

 

Very nice write up!
The airlift is one of my favorite tools and I used it over the weekend when I replaced 5 coolant hoses.

 

Sorry to revive this old thread, however I plan to change my coolant in the near future and wanted to be sure about the coolant capacity of the 996TT. The procedure here indicates a capacity of 6 gallons, however the manual shows a capacity of 28.5 liters which equates to 7.5 US gallons. Could someone clarify which is correct?


Great write-up BTW.


John

 

So can anyone recommend a good source for 6 gallons of coolant? Pentosin from Napa? Audi/VW G12 coolant? Or the full monty sourced from Porsche dealership?

 

Audi/VW G12. Don't waste your money on the Porsche branded stuff. It's exactly the same as G12. Definitely don't put Pentosin in there, it hydraulic fluid.

 

So more specifically, Amazon has gallon containers of Audi Coolant Antifreeze Antigel Refrigerant (Part No. G013A8J1G) for ~$27. These are concentrated, so would need diluting ~50/50 with distilled water.

3 gallons of this stuff should set me up pretty. Thanks!

 

Nice writeup.

 

Pentosin is a German BRAND name, not a product type, while they are very well known for the hydraulic steering fluid CHF202 they also make other specialty fluids like ATF1 for Tiptronic , PDK fluid , also brake fluid and yes antifreeze.

 

Gotcha. I hadn't seen anything except their hydraulic fluid.