Can't believe this--broken coolant cap?

So I went to check my coolant last night. It was dark, so I opened the cap to check it. Put cap back on, went to sleep. This morning, drove to work and found coolant all over inside of engine, and pool under car. Could I have cracked the cap? Is it that easy to crack it? I've tried taking it off and readusting...still spilling out the top. Dealer says if I've lost coolant (regardless of the cause), that it's not just a matter of replacing the cap and adding coolant. Rather, they'll need to completely flush the system since the lost coolant was replaced with air. Suggestions? Thoughts? Do the caps break that easily? Frustrated, as I was just trying to do a spot check...and wound up breaking it.

The caps were warranty issues some time ago.

I had the same issue. I replaced the cap, no other problems since.

Woody, did you need to flush the system? Or just replace the cap and add some coolant/water? Any other experiences out there with these caps? Can they bust or strip just from opening and closing them?

I didn't have to add any coolant or water, I only lost a small amount of coolant. I didn't flush the system and have not had any problems. I'm not sure if I was supposed to or not. Most people have to replace their caps or their entire coolant tank, it is a common problem. I would try getting a new cap and see what happens, they aren't expensive.

Also, there is a write up by Loren on Renntech on how to change your coolant tank. I think there is a part in there on how to purge the system if you want to do this.

Thanks again Woody, new coolant cap is on its way. I'll update with results. Any other thoughts in the meantime by anyone with similar issues would be appreciated. Thanks

fyi, porsche coolant system is pressured. u have to tight up the cap, otherwise it would make a mess.

No problem, here is Loren's link for coolant tank replacement. http://www.renntech.org/forums/index.php?showtopic=8024

How empty did it get? If it got really really empty, then yeah you have to flush, but if all it did was empty out some (even if the expansion tank was dry) no need to flush. Heck, even if it got close to emptying, you don't have to flush, just idle the car for a while (a good long while, like long enough for the engine to get to operating temp and stay there for a minute) with the cap off the tank and the heater on. If there's still any air, some driving on the highway (with the cap ON tightly of course) with the heater on should work it out of the system. Oh, and I'm assuming that when you fill it with antifreeze/water you refill it with the same brand as what was in there before.

I bet you didn't put the cap back correctly. I'd replenish coolant and distilled water at 50/50 mix. I don't think coolant flush is needed. Use only Porsche coolant as it's not compatible with off the shelf coolant. It's very expensive though. Replace the cap if it's damaged.

Guys, I can't thank you enough for the tips. The new coolant cap arrived (via my "runner" (wife)). I swapped the old one out (the original apparently-part number ending in "00") and put the new one on. No more leaks! Can't express how relieved I feel right now. Although I'm sure you all know the feeling. Now I'm just wondering what other recalls have gone uncorrected on the car...hope I don't find out about those the "hard way". Thanks again.

The point that Djantlive made is quite common. The cap can sometimes be a little tricky to get on correctly. I've see several times where the cap was put on where the threads didn't match up correctly, kind of like cross threading. Bleeding is tricky. Using the factory tool works pretty good. Basically, it sucks most everything out of the system. Then by reversing the tool, it will put antifreeze back into the system, as the system will suck in the antifreeze. Without this tool, you would need to fill up the system, wait for the thermostat to open and continue to fill. Allow it to cool and top off again. Basic rule is , if the system is completely empty, it will take 2 gal of factory antifreeze plus water. If only a water pump is replaced, 1 gal plus water. Porsche claims the factory antifreeze is "Lifetime". I question this. I have noticed some deposit build up in some radiators. I'm starting to believe it would be a good idea to replace the antifreeze every 3 years. Of course I would only use the factory antifreeze. I would be interested to hear any issues others have experienced regarding their cooling systems.

Check the link woody gave. The followup article in the link (2nd post) is by me - so I've done this too. Basically 1a) if you've lost too much coolant, buy porsche coolant, mix 50%/50% with water. Add this 1b) if you've lost little top off with water 2) Put your new cap on, turn bleeder valve open (up) 3) drive for 30 minutes (car will "burp" out air) 4) cool off for 5 hours 5) Add more coolant 6) CLOSE bleeder value and cap 6) Drive for 10-15 more hours over the next few days 7) your car might burp any residual air 8) cool for 5 hours 9) add coolant. 10) drive on, but just watch the coolant light on the temp guage if it ever goes on for the enxt 3-4 days of driving. Basically the 1st burp will be a definite one and happens quickly. The next (if any at all) takes some time - small bubbles accumulating. Remember you have almost several (5?) gallons of coolant in there. A cup or so missing isin't anything. Sid PS: Don't play car-tech in the dark next time - just go to sleep

Thanks again guys. It appears I didn't lose as much as I thought. With (what appeared to be) a lot of coolant on the engine and a small puddle below, I added about 8 oz of tap water since I didn't have any coolant handy. Drove home, and let it sit over night. Checked this morning and I actually may have added a little TOO much. It all depends on how one reads the coolant tank measurement. I don't have a picture, but I'll attempt to draw it below. The "min" line is clearly designated with an up arrow. The max however, sits next to a box rather than an arrow. Is the the bottom of that "max" box the maximum, or is it the top of that max "box". Why couldn't there just be two plain lines to make it easy?

Not to freak you out but I think we failed to mention you should use distilled water not tap water. Sorry, I would think with that small of an amount it should be ok.

Good grief. Well, now I'm sufficiently freaked out once again. Can anyone else attest to the 8 oz of "tap" water I naively added being okay to live with? And assuming the bottom of the "max" box is in fact the line to go by, I plan to simply siphon off a few oz from the top. Any issues with that, or special precautions? Sorry if these questions seem obvious, but I'm convinced I've done my car more harm than good thus far acting with MY best intentions. So I'm attempting to verify anything I do now BEFORE I do it. Thanks

At this point, since you have no idea EXACTLY what is in the water (minerals, impurities, etc.) you might want to just bite the bullet and flush and fill your coolant. It will be a little pricey but it is the safest way to make sure any contaminants that might have been in the water have been removed. $100 (I'm just estimating) in time and materials versus a $10K engine is worth that piece of mind in my book.

What kind of water do you think the shops use when they flush your coolant? You think they're using distilled? No sir. Furthermore, distilled isn't even the best, filtered is...something about distilled water having a greater tendency to ionize or something. 8 oz of anything wouldn't matter, but as long as you still have between a 50/50 or 35antifreeze/65water ratio no amount of regular water matters.

Thanks Marlinspike, you're helping me sleep tonight. Also, with such minimal lose...do I need to worry about air having been introduced to the system? Is any "burping" required?

If it only lost one cup then the expansion tank didn't even empty right? Then I wouldn't worry about air, though if the temp starts acting funny then it may be worth just doing a drive on the highway with the heater on and checking the the coolant level (after the system has had a chance to cool of course, you don't want coolant spraying on you). I may as well add that back in the day when Mercedes' owner's manuals told you how to take care of your car (not just how to use it), they actually specified using regular water.

Guys relax. Using regular tap water is fine. Here in San Diego at least the tap water is damn clean. In fact sometime back when the tap water wasn't the best they sent everyone a notice (level of xyz is abc%). I checked up online and that was still above the World Health Organisation's standards of what constitutes drinking water. I've also seen dealerships put regular water PLUS the porsche tech told me that in the US tap water is good enough for drinking so we're ok. Remember, they have to print this due to liability reasons ("I put seawater and my engine died - sue porsche"). Finally, PLEASE cleanup that coolant that's fallen inside the engine chamber. Coolant is a corrosive material and will eat into your paint over long periods. Please wash it off/wipe it off soon. Sid PS: Don't worry too much. Its "just a car" . Think of how you'll react if someone dings your door etc. So chill ...

Will do Sids, thanks. Any thoughts on reading that coolant max mark? Is it the top of the box or the bottom?

Hmmm, I can't recall from the top of my head. But I think they have an ridge on the inner wall of the tank which can be seen from the hole (cap off). That coincides with the max level I think. When in doubt, just call your nearest dealership. Their tech will very gladly answer this for you. Sorry !