hcrobinson

I have just gone throught the procedure described in the Porsche workshop manual and in some threads on the internet. They state that fuse B1 has to be removed if the car has tiptronic so that a shut off valve stays open when the car is started and revved up to remove air from the system.

Temperature and revs have to be monitored. Problem: fuse B1 also controls the instrument panel (and the diagnostic socket), so impossible to monitor temp and revs with the fuse out.

Someone must have had the same problem. Help!!

Car is 996, C4 cabriolet with tiptronic

dotframe

Maybe use an obd2 tool like durametric or even a cheap Bluetooth or wifi dongle and iPhone app?

hcrobinson

As i mentioned fuse B1 also controls the diagnostics, so the socket is dead. I tried an OBD reader - nothing.

Jackstand Louie

Not sure if this is helpful but did you use an airlift before refilling? I don't have tiptronic but when i used the airlift after replacing the waterpump and thermostat (and throughly draining the system) I had very little air. In maybe 200 miles of driving I added less than 1/2 pint of fluid to top off and havent added any since.

If so, you may not have a problem.

hcrobinson

Did not use an Airlift. Managed to get 19.5 litres of coolant in, I think capcity is 22.5. Will check tomorrow and top up after a drive.

Jackstand Louie

Look for steep angles, slopes, hills, off/on ramps, etc. Gravity works really well and its cheap.

jordanturbo

What kind of Mileage do you have on your car? Why are you refilling? Porsche coolant is supposedly a life time coolant and should not have to be changed in a regular interval. I did mine once, but only because I had a fitting break

hcrobinson

18000 miles! Rubber hose sprung a leak, actually a t-piece came apart where the tiptronic cooler pipe comes off the main back to front pipe.

Most of the coolant drained out via the leak.

Hurdigurdiman

If you managed to get 19.5 ltr of coolant in the system then forget about the fuse and start the car. Open manually the breather at the top of the fill up tank. Better known as the burper valve and drive the car. Don't hammer it and take along some coolant. You may even see the 250 degree mark light up but dont worry (its only saying theres not enough coolant in the system yet) thats another one of the 1000 things we didn't know about the 996. Switch off, let her cool down a bit and top up the plastic filler tank (if needed) and drive again. Even though its a triptronic I can't see what differance that would make in doing a complete coolant change and in any case, are you sure you lost ALL of your coolant before starting the work? I think not. I didn't use an airlift. Did mine the 'old fashioned way' and is fine but mine not tiptronic. If you are sure that no one (APO) has been messing with the electrical side of your fuse box and you removed the fuse and it didn't work, then do the job anyway like I suggest. Keep that burper valve open for a few days and carry the coolant along with you. Only fill the plastic filler half way.

CBR786

+1 good advice I did it that way plus when running car I had heater on I think to let the valves open up thermostat to open it will cause the red temp warning led to flash let car cool down properly then topped up