Eurocarguy911

Hello Rennlisters!

I've been working on this car for several months now. It's chronicled here. https://rennlist.com/forums/996-foru...r-project.html

I go the thing to run and am blowing a misfire on cylinder 1 code. Tracking that down. I have only driven it 20 miles or so in 3 trips.

I'm back to the loosing coolant like crazy scene which I chronicled here. https://rennlist.com/forums/996-foru...lant-leak.html There is UV dye in the system which is why the color of the coolant is not pink.

I thought I had it resolved by putting on a new cap. It is spewing coolant like crazy. Does that cap just need to really tightened up hard?

The car ran this morning for a few miles. I was stopped at a red light when I heard a rushing noise. I thought it was the SAI system coming on. Then there was steam rising up from the back of the car.

So I pulled it over to an Urgent Care place figuring it may help. Maybe I was wrong on that count. I was able to observe it gushing coolant into the overflow catch "pan" that's integrated into the coolant tank. It did it for several seconds. Long enough to take pix and then figure I should take video. It came to a stop at the end of the video.

You can see it gushing for the first few seconds. It did that for 20 or 30 seconds or so.

Eurocarguy911

Carlo D

Did you leave the burp valve upright position while driving? Leave it up like I did. You likely have plenty of air in the system like I did.
Funny thing is i didn't have this issue while driving the car (except that one time at gas station) but rather mostly when car was
idling and attempting to fill with coolant. I find that the cap only needs to be tightened until initially cannot be turned anymore.
The air should be released around the blue cap as it has that pressure release valve on it.

DBJoe996

There is something wrong with that cap. I would replace the cap immediately and make sure the seal is in place (inside the cap). And yes, it must be very tight on the coolant tank.

TRLBRAKER

Ensure all the air is evacuated from the system and replace the cap with a new Porsche one since they are cheap.

At first glance at the picture it appeared as if you sprayed coolant on the back of the Red Toyota parked several slots down!

Eurocarguy911

Interesting reflection and thank you.

This was the first time I ran the car with the burp valve in the down position. I left it up for the first 15 miles. I guess I thought I got all the air out.

Mine also happened at idle at a red light.

Yay!

Eurocarguy911

The cap has about 2K miles on it. Bought it with in the last year.

I think I'm not tightening it hard enough.

Eurocarguy911

Green tape on the Toyota!

Elumere

I’ve had the same happen - despite a cap that turned out to perfectly functioning. The culprit was large air bubbles within the system. As soon as I came to a stop/turned off the engine, coolant came gushing out (half a gallon at minimum).

Apparently, coolant needs the vacuum to keep its pressure/heat in check. Air bubbles allow the coolant to cook, triggering the 15psi lock on the coolant cap.

jdbornem

From your other thread on coolant refill issues, last I saw, you still had a gallon or so left to fill, yes? That's alot of air to expand when hot, and you seem to have been dealing with this for a while.

At what point do you think you might drain all the coolant, get an AirLift to vacuum the system, and try to refill that way?
https://rennlist.com/forums/996-foru...pump-tips.html

I used the linked method, and an AirLift. Drove for a week with the bail up, added only 200mL total after the initial fill. It was very easy with no issues.

Carlo D

since you won't have problem filling with a vacuum unit just get it done this way. the reason why i didn't is that i couldn't maintain negative pressure (due to a likely leak in the expansion tank) using the Maddox kit i bought from harborfreight.
the kit itself is well made with the adapter appropriate for our tank opening. $74.99 --- cheaper than Uview. Of course you need a pneumatic air compressor as well. Get the McGraw 3 gallon pancake compressor for $69.99 and the appropriate hose/connectors for couple of bucks. I suggest also getting some plumber thread sealing tape to use on the output of the compressor and the tubing as i had leaks through that as well.

https://www.harborfreight.com/coolin...ressure+tester

https://www.harborfreight.com/air-to...sor-57567.html

they have both in stock at their store in Nashville.

hate to see those precious pricey porsche coolant going to waste.

Billup

Does it not leak coolant when you start it with the trunk open? Seems quite heavy to not see something while the car idles, maybe try driving slow while someone watches with the trunk open. A lot is on top, and gravity generally pulls the downward direction. Air bubbles is the only other thought that was mentioned.

Eurocarguy911

Well now this is an interesting take, and an obvious one. Yes, I keep fighting with it figuring I can do it with out the vacuum tool. Initially it was the cap and that got resolved.. Now it's getting it filled after dropping some hoses near the engine.

The reason i though this method could work when only cracking the system at the rear is because I have read about folks doing it here. "All you gotta do is pop the tab up for a while". Which I did and thought it was good. this morning was the first time I flipped the tab down.

It holds pressure over night so there are no leaks. It's surprising how much different this machine is from everything else I have worked on. Been working on foreign and domestic cars for 40 years. this is my first Porsche.

All is well. Thank you for your insight

Eurocarguy911

Mine is holding pressure over night. So agreed to problems there.
I do have an air compressor so that is good to go.

Thanks for taking the time to help with this. It seems we are both in the same boat, at least a little bit. How is your car doing?

Carlo D

Car is fine. Haven't had the need to fill it for several days. No overflow.
I've stopped keeping the burp valve upright. The other day it remained up on its own. Again no overflow.
I must had not completely drained out all the old coolant as i originally thought.
I was not able to accurately measure the volume discarded as some ended on the floor haha.
But i did have at least 4.5 gallons that i was able to collect and appropriately discard.
Funny cause I used the method described before to use compressed air to force fluids out.
I do keep half a gallon of coolant in the frunk in case it needs some in future. Temp is stable w/ spirited driving.
For you --- just keep the valve upright for several more days, go for several drives, and keep eye on the temp.
Once i decide to replace the expansion tank i will absolutely perform the vacuum method as everyone
seems so damn keen in suggesting over and over haha.