coolant cap popped off

[mustang2porsche]

Is there any reason why my coolant cap would blow off of my 2000 boxster S. Was on the interstate last night when all of a sudden I smell coolant and temp needle when past the 0 on 180. Luckily I stopped at a has station that sold distilled water but had to add a gallon and a half... any ideas?

[Luckyed]

Did you have the cap off recently for anything?

[mustang2porsche]

Nope, haven't touched it since I bought it in march.

[j.fro]

check your oil... hope the level isn't unusually high.

[Burg Boxster]

In a nutshell, system compromised somewhere allowing air in which is causing boilover...

Typical suspects:
- cracked coolant reservoir tank
- bad coolant cap (what are last 2 digits - hint .04 is latest revision)
- water pump
- reservoir overflow valve bad

Don't just start throwing $ at parts... start w/ a simple pressure test on system to identify compromised component. There are obviously others and some catestrophic but let's not even think along those lines.

Good luck

[mustang2porsche]

Found out my front left radiator is leaking yesterday, puddle of coolant plus water spots everywhere. Must've lost coolant and caused the boilover. Oh well pelican parts here I come.

Also my coolant cap is black and doesn't have any part numbers, I'll change it anyway because I used to have a blue cap with the .04 at the end.

[mustang2porsche]

So O'Reilly had my radiator, replaced it, and test drove it and it's still loosing coolant somewhere in the front left side of the car. The wheel well is coveted is coolant. My next bet would be hoses but is there anything else. It also doesn't seem to loose coolant at idle, while I was re assembling the bumper it never ran hot or loss coolant.

[BYprodriver]

Originally Posted by mustang2porsche

Is there any reason why my coolant cap would blow off of my 2000 boxster S. Was on the interstate last night when all of a sudden I smell coolant and temp needle when past the 0 on 180. Luckily I stopped at a has station that sold distilled water but had to add a gallon and a half... any ideas?

You need to have your coolant system pressure tested.

[mustang2porsche]

Originally Posted by BYprodriver

You need to have your coolant system pressure tested.

If changing the hoses and new coolant cap don't cure it, I'll have it put into a shop for pressure testing. I can't make no out of town trips loosing coolant/distilled water time I drive for more than 15 mins.

[jcslocum]

There is a hose that runs up over the left front wheel that is part of the radiator vent system Maybe you have a cracked or loose hose.

Getting the air out of this system is a real bear. It's a long system with lots of places for air to trap. It can take weeks of topping up to get it all out.