Advice on overheating

Hi there, I had issue this evening, with low coolant warning. The car started to overheat and got to over 225 before I could turn it off and let it cool down. I was at a gas station, got some water and opened the rear cap , there was some steam and adding water caused it to overflow a bit. I waited a while then drove couple miles to home with heat on, air was hot, then not and it started to overheat again and low coolant light came on again. Got it home, waited a while and checked levels, added about added about 4 cups of water and the levels now looked good. Have left car sitting since. Couple questions, could a brief overheating like this cause issues? I did not see an obvious leak, but will open up engine access bay in morning to look further. Car is a 2007 Boxster, I have had it several years and never added or changed coolant till today. Could it just have been low from time? Best thoughts on how to proceed, in checking and ruling things out? Thank you, Jack

Check for coolant seepage around the water pump. The other item that you may want to think about is the thermostat. Those two items and/or any obvious hose leaks. Usually you will see antifreeze on your floor if its leaking badly. How many miles have you put on the car?

There are only 17k miles on the car, was a close friend of mines and he passed away so I baby it. No leaks on ground, and overall maybe 6 or 7 cups of water added to fill it all the way back up. Thank you for your reply.

Assuming I should I just test car tomorrow first, get it up to temp in garage and see if I have issues? Is that a normal enough amount of coolant to be missing? I know opening the fill cap made me lose some of that when engine was hot so I don't think it was that low overall. Jack

Air bubbles are hard to get out of the coolant system. Check your antifreeze before startup and fill to the lower level line. May need to do this job 3 or 4 times to get all the air out of the system. What year is your car with 17k miles on it. If its a garage queen, you may need it serviced more often and change the oil once a year. I routinely let my engine warm up for 3-4 minutes before leaving my driveway. I bought it with 22k miles a few years ago, now with 40k without any unusual problems.

Its a 2005. I do change oil every year. Jack

Some ideas: 1. Confirm serpentine belt is still there by opening hatch behind seats (not hard to do). 2. Look for water pump pulley condition. Mine sheared off when the pump shaft seized. 3. Unseat, clean, and reseat the coolant cap . Get all white crusty junk off. The caps are a finesse fit, so don't under estimate the seating tolerances. These can leak lots of fluid over time with little indication. 4. Open the cap on the engine bay overfill reservoir with engine cold. Check cap seating and look for fluid condition. Again, seeping can happen there, so look for white stains around the cap . 5. Purging air is a bitch on these cars, but you can read up online about using the small pressure valve with the squared metal handle atop the reservoir. 6. Look at your oil via the oil filter (no need to drain) by just removing it. The rest of the oil in the engine wont flow out because it sits above the sump. If it is milky coolant may have gotten into the engine proper. Google that and bring a box of kleenex. 7. Careful with adding just water. Follow Porsche fluid mix requirements carefully. If the current mix is wrong you may have hit a tipping point. 8. Consider that the water pump rotor inside the housing has been known to break off from the shaft. Thus, no mechanical circulation but the belt and pulley seem fine. 9. Not sure it is a best practice, but you can force the radiator fans on for the two front systems by turning AC on with cabin recirculation also set to the on position. Then use an OBDII reader I use and like OBDII Link Bluetooth device) and check actual temps (the dash gauge is heavily normalized out and not accurate). Let us know what you find. Sent from my VS995 using Tapatalk

1) You said "over 225" but not how much "over", But brief overheating is unlikely to cause issues. And yes it is possible to loose coolant slowly over time. I believe Porsche recommends coolant flush and fill around 4 years. If you do not know when it was done last I suggest you get it done. Porsche or your Indy can at the same time check for leaks. Good luck.

It did not go all the way to right on gauge but close, but only for less 30 seconds or so till I could get it off. 1. Confirm serpentine belt is still there by opening hatch behind seats (not hard to do). ****Opened up everything and all the belts seem to be fine 2. Look for water pump pulley condition. Mine sheared off when the pump shaft seized. ****Took some pictures it looks good, also took video will upload 3. Unseat, clean, and reseat the coolant cap. Get all white crusty junk off. The caps are a finesse fit, so don't under estimate the seating tolerances. These can leak lots of fluid over time with little indication. ****Took pic of this, mine was clean, pic is before I cleaned it 4. Open the cap on the engine bay overfill reservoir with engine cold. Check cap seating and look for fluid condition. Again, seeping can happen there, so look for white stains around the cap. *****I cannot see this, am I missing something simple? 5. Purging air is a bitch on these cars, but you can read up online about using the small pressure valve with the squared metal handle atop the reservoir. ****Thinking I will do a fluid change shortly 6. Look at your oil via the oil filter (no need to drain) by just removing it. The rest of the oil in the engine wont flow out because it sits above the sump. If it is milky coolant may have gotten into the engine proper. Google that and bring a box of kleenex. *****Will change oil tomorrow and check 7. Careful with adding just water. Follow Porsche fluid mix requirements carefully. If the current mix is wrong you may have hit a tipping point. ***Will not drive till I have it refilled 8. Consider that the water pump rotor inside the housing has been known to break off from the shaft. Thus, no mechanical circulation but the belt and pulley seem fine. *****Started car, no issues, and took video 9. Not sure it is a best practice, but you can force the radiator fans on for the two front systems by turning AC on with cabin recirculation also set to the on position. Then use an OBDII reader I use and like OBDII Link Bluetooth device) and check actual temps (the dash gauge is heavily normalized out and not accurate). ****Will try and figure this out Here is a link to the other pics and the video: https://photos.app.goo.gl/PghzpZDAii2RkRtAA Thank you!

Sorry on #4, was thinking Cayman not Boxster...not sure the location config of the overflow. Hoping wrong coolant mix, maybe bad thermostat, bubbles, and low levels. Those are cheap fixes. Let us know how the oil looks. Edit: And as a data point, when my pump seized and threw off the belt, my temp went to red fairly quickly. Pulled over, let temps fall, and nursed along like that for 3 miles. No signs of issues since.

Engine bay coolant cap will be inside the engine bay, of course (gotta remove the topside engine cover) and it's on the right side (US passenger side) of the car. It should have a blue cap similar to the one in the trunk.

In my Cayman the overflow reservoir is where I marked (green dot) on OP pic from his link above. Methinks Boxster tank must be in a different place because of the convertible hardware...dunno. Sent from my VS995 using Tapatalk

Firstly, thank you all for replying. I really appreciate it. Changed the oil, was all good looked perfectly normal. Next steps are to change out the coolant, and the serpentine belt as it is right there and i have all the panels off. It looks perfect after 17k miles but it is 12 years old. I also bought a Cooling System Refiller Kit, which should kinda help me figure out if there is a leak per this article and help avoid air pockets when filling: Flush Coolant System Seeing as the waterpump is belt driven, and it does not look like it is wobbly, is there any other way to check if it is bad? There are no leaks that I can see. I still have no idea where the other ap would be, the only other pics showed it on the right, like Meatful posted... Thanks again, Jack

Here is an Autoatlanta parts explosion for reference. M97.20/21/22 Water Cooling 4 We need a 987 Boxster owner to chime in and confirm the reservoir location. Sent from my VS995 using Tapatalk

Because you have everything opened up, changing a 12-yr old water pump might be a good idea.

It does not seem like a horrible job to do that, is thermostat fine or just do it at same time? Also, any of the hoses worth doing, they all seemed supple enough but if I can easily access and remove them I don't mind doing it. Bear in mind there is only 17k miles on the car. Jack

I had my car overheating like yours once. I stopped imidiatelly and have it towed to the dealer. Turned out it was a faulty reservoir cap . Sometimes they go bad and the water vaporize. Try to get a new cap and see if it solve it.

Unfortunately, the search function on this site is down. My recollection is that the water pump is treated as a maintenance item by some here because of know failure rates. Not so the thermostat (by my imperfect memory).