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Hurdi,
The blue cap, 996 106 447 04= latest rev #, has the pressure relief built in to it. (take one apart you will see)
The black unit with the bail is a spring loaded diaphragm 'vacuum break' valve, not pressure relief.. When you have the bail up it holds the diaphragm up as the engine cools this forces the valve to open.
When the valve is open the system can vent to the atmosphere allowing air bubbles to escape. On a cold start,with the bail up, as the coolant warms up it pushes out air pockets.
That is why you should start with a cold engine, bail up, when you are using the start it, rev it to various RPMs, method of bleeding the system.
Look at the valve when your engine is hot. The square peg that the bail mounts on is up, hard against the top of the unit without the bail up. With no coolant venting.
Take one apart. You will get a better idea how it works.
Wait... How did we miss this...?
Why is your coolant green?!
It should be pink!
Porsche has had 3 different coolant colors. First was green, second yellow and now pink. Coolant is i believe a lifetime fluid so there is no need to change it..
I took delivery of my 1999 Carrera 996 Cabriolet yesterday and drove it 3 hours on the highway without issue. In the last 10 mins, we hit some traffic, and I noticed the water temperature increased from about 190F to maybe 210 at the highest point in the drive. I started noticing white steam in my review mirror. When I pulled into the driveway, white steam was coming out of the engine cover. I opened the hood and saw coolant everywhere. I noticed there was no cap on the coolant reservoir...
I told the dealer that sold it to me that either the cap loosened itself on the drive or it may simply have not been installed after they checked all the fluids before I picked it up.
Could it be possible that I drove the whole time without a cap? I was running at highway speeds the whole time for 3 hours, and outside temps were in the 50s. It was only until we hit bumper to bumper traffic that I noticed the temps creeping up.
I'll get a new cap today, but should I now concern myself with draining the coolant and purging it of air?
Could it be possible that I drove the whole time without a cap? I was running at highway speeds the whole time for 3 hours, and outside temps were in the 50s. It was only until we hit bumper to bumper traffic that I noticed the temps creeping up.
I'll get a new cap today, but should I now concern myself with draining the coolant and purging it of air?
Was the coolant reservoir completely empty when you arrived home?
Well, good news is that you drove it during cooler ambient temps and didn't damage the engine. Something like this is not totally uncommon IMHO. The dealer may have had one of the mechanics check all the fluids and either he didn't replace the cap or didn't tighten it properly.
IMHO, I would purchase some OEM Porsche coolant, properly mix with distilled water, and refill the coolant reservoir before flushing the system.
Others here on RL can tell you a better procedure for "burping'" the system.
When the engine has cooled down, check that the coolant level is at least at the minimum level. If not, fill to that point with a 50/50 mix of distilled water and Porsche coolant. Put on your new cap, pop the bleeder valve in the up position with the little wire clip and go through several drive cycles (hot/cool/hot/cool) while checking the coolant level after each drive. You should be okay with that. No need to drain the coolant. With the bleeder valve in the up position it will purge any air in the system.
b3freak and DBJoe996 - Your advice worked. I only ended up adding a liter of fluid (500ml of Porsche coolant and 500ml of distilled water). I ran it through a couple of cycles, no issues. I don't think I lost enough coolant from the reservoir to warrant any flushing, as I don't think there was any air in the system.
By the way, why does this car hold 6 gallons of coolant? My buddy's 13-liter tractor-trailer rig holds 9. Where does all that fluid actually fit? Seems like an excessive amount of coolant, even with hoses going to the front and back.
By the way, why does this car hold 6 gallons of coolant? My buddy's 13-liter tractor-trailer rig holds 9. Where does all that fluid actually fit? Seems like an excessive amount of coolant, even with hoses going to the front and back.
Yea, that's a lot of fluid ain't it?
The main reason is the distance from the rads to the engine. Basic physics... engine in back - rads in front... you add the length and amount of hoses and you'll eat up 6 gallons easy.
Heck, my water heater is on the other end of the house. I have to bleed about three or four gallons of water each time I want to take a shower and I'm on city water (charge/gallon used). (sniffle)
The main reason is the distance from the rads to the engine. Basic physics... engine in back - rads in front... you add the length and amount of hoses and you'll eat up 6 gallons easy.
Heck, my water heater is on the other end of the house. I have to bleed about three or four gallons of water each time I want to take a shower and I'm on city water (charge/gallon used). (sniffle)
Because I kept coming back here when troubleshooting my problem (bubbling through bleeder valve / the one that lifts), I wanted to update the forum. Well... in my case it was a non-original, ****ty bleeder valve fitted. It had a tiny hole in the sidewall, and the quality is all round not "just like OEM"... See photo comparison with Porsche original on the left. What's even worse is that it was fitted by a reputable speedshop after my reservoir cracked (beware!). I managed to swap just the bleeder valve with the reservoir still in the car. All my problems are now gone. YMMV.
If you topped off recently as you said, then there is nothing wrong with anything. The coolant expanded as it heated up and found a way out of the system via the lift up valve. Don't buy anything.
I had leak on a 95 degree day..no overheating but lost a few quarts of coolant.My tech guy pressure teated...ran and drove the car could not duplicate the ussue.I did get a new Aos installed.I also orderedthe bewest cap...a blue one.Seems to be all ok now..
12-22-2014 | 04:17 AM
