Help - my car just errupted coolant!

I took my car to the mechanic this past week to get inspected before my DE this upcoming weekend. While there he told me I should purchase a new coolant tank cap because it seemed the old one might fail some time soon. So I purchased the new one and topped off the coolant tank with a little bit of distilled water. After driving it for a few minutes when I returned I noticed that it was leaking just a little bit. I didn't think it was a big deal and continued driving. This was on Saturday. I drove it for the past few days and no more leaks and everything seemed fine. Now as I pull into my garage I'm getting everything ready when I hear this spray of water coming from my car. I open the hood and find that there is coolant spewing from the top of my expansion tank. It continued for about 30 seconds and then stopped. From what I can tell my expansion tank is now basically empty. While driving it the car didn't show any unusual symptoms and the temperature stayed at 180. It just happened after I shut it down and let it sit for a moment. I'll go see if the cap is loose but I tightened up pretty well when I installed it so why should it loosen up after a couple days of use? Help! I have a DE on Saturday!!!

Ok I just checked the cap and it was able to be tightened by about 1/8th of a turn. Would this be the cause of my eruption?

Refill and take it for a drive. That should tell you. Wait until the engine cools before adding water/coolant to avoid temperature shock damage.

Did you get the correct cap?

Quotes source posts: 8426850, 8427019

Just went to the VW dealer to get some coolant. It was too much to replace with just water and the Porsche dealer is closed. About to take it for a drive so we'll see what it does... I'm pretty sure it is. I kept the old one and these two look identical. I'll just make sure to tighten this one up really well this time!

Depending upon how low you were on coolant when you topped off, it's possible that you trapped some air in the system. If so, it will burp like that several times until you get it all out. Flip the metal lever up on the overflow tank cap, drive it a bit. Let it cool a bit, and slowly open the cap and let it vent a bit. Do this several times, and you will clear the system of air.

Quotes source post: 8427052

I'm not sure where the metal lever on the overflow cap is located? I just took it for a drive and it dropped the level of the coolant by quite a bit. I'm thinking that's because the thermostat opened when I drove it. So I'll let it cool off a little and add more coolant. Can I just open the cap after every drive and bleed air out that way? Or is it best to do what you described above? Thanks for the help!

I just went outside to remove the cap and figure out where this bleeder valve is. I just took this photo. Is the valve the metal bracket that I pulled "UP" for this photo? It was down before, not sure if that's it?

Quotes source post: 8427151

Yup, that's the valve. Sorry, I remembered it's location wrong. I'd drive it, bleed it, drive it, bleed it,... several times before trying to go any kind of distance just in case there is something else wrong. Based on your comment about the level dropping considerably, I suspect we are on the right track.

Sounds like they didn't bleed the system well enough and an air pocket release. This is normal after doing this work and it can happen in the first couple of thermal cycles.

so the way I read this: your car was fine, your mechanic suggested to be prepared, you opened your system to "do the right thing" and add water - but didnt close the cap, then coolant spewed out... what's that old saying - if it aint broke keep trying! glad it sounds like a simple fix....sure it was a tad scary for a minute there

Thanks for the help everyone. I hopefully have it under control now. I'll keep a close eye on it in the next few days and make sure to bring coolant along with me for the DE. Fortunately the drive to the track is about 3 hours so maybe that will get the last few bubbles out. Ivangene - actually the mechanic suggested the fix to me. I'm the one who performed the duty so I can only blame myself! But it does make a good point where I never had any radiator issues before and now I had a mini-volcano in my car earlier this evening. Ah well, the joys of DIY work.

Updates? I guess the car is running well.

Quotes source post: 8427498

hey, I know ALL TO WELL those joys... my car is without any rear suspension and yesterday a pile of crap arrived....nothing I want to use...now I am facing a choice of waiting another week and trying another brand, making my own, or somehow modifing the garbage they sent me....oh joy I was just messin with you - all in good fun

Quotes source posts: 8433863, 8433968

So far so good...After I've come home from work for the last couple of days I release the pressure and lift the little valve up. Each time I'll do it results in some hissing. I'll do it again after my 3 hour trip to the track tonight. Hopefully everything should be bled after that. In any case I'm bringing my coolant and some distilled water with me. You never know... Trust me this isn't the first time I've done something stupid. But it's all a learning experience and now I know for the next time!

yup.... I normally do everything at least twice... the first time to fix it, the second time to fix the fix......

A little coolant on the track never hurt anyone ouch

Quotes source posts: 8434054, 8434070

That applies for me not only on cars but on around-the-home projects as well! Yeah you'll hear the guys on Rennlist talking about how some idiot leaked coolant on the track and had to have it shut down for a few hours to fix!

oh for sure - house repairs are a 3 fer... once to figure it out, once to correct it and once to change your mind now that you know how to do it

Closing this thread out for the archives... The problem must have been air in the system. After releasing the pressure every day (for three days) and lifting the bleeder valve I was able run the car through an entire DE weekend without incident. So although the eruption caused me to panic, it just just a matter of my car needing to burp a bit.