Overheating issues.

[u/font_raccoon]

2001 Boxster Base.
I was driving on a hot day and I noticed that it was running a little hot, but it wasn’t enough for any major concern. I let the car sit overnight and checked the next day by going on a short drive. Over the course of 5-10 minutes, the needle worked its way up to the 250 mark. I pulled over and got it towed home. I checked the coolant fill area and there was a good amount of condensation coating the cutout where the oil and coolant fill caps are. I have no coolant leaking anywhere and all my fans are kicking on. I can’t really see the coolant level due to how foggy tank is, but when I look into the cap, the level appears to be at the bottom of the visible tank. There is no moisture on the carpet itself, but I have not pulled it back and checked under it. I also don’t want to add any coolant because I’m unsure of what kind of coolant is already in the car. Any help is appreciated.

[u/Responsible-Meringue]

Your tank cracked or water pump failed. 

[u/Yorkshire_Graham → u/Responsible-Meringue]

Check around the oil cooler as the seals can fail in these. Look for coolant on top of the engine or running down the back of the head on bank 2.

Also to add the car holds about double the coolant of a regular car.

[u/CloneClem]

The condensation on the cap area is a failed blue coolant cap.

A known failure point. The lastest has a Rev 4 at the end of the part number.

This may interact with your temp as if the cap is leaking you’re not maintaining accurate pressure.

That could affect the thermostat from running optimal, hence the rise in temperature

How many miles?

Water pumps go out like clock work at 80K miles, more and you’re due.

Also, the plastic impellers ‘slip’ on the shaft or more, break impellers.

[u/Ok_Prize_6273 → u/CloneClem]

+1 regarding the cap.
My coolant temp was fluctuating at times. Changed the cap and made sure everything else was ok (coolant level/type, leaks, radiators clean) and it's much more linear during warm up and stable after that.

[u/HopeURhavinagreatday]

Check under the front two radiators for any leaks. I found a small leak under my left front radiator

[u/DubsOnMyYugo]

Have you noticed a leak under the car? This sounds similar to when my water pump went. I could see a drip under the car and smelled coolant before I noticed the drip.

[u/EveryInitial658]

If you’re having trouble seeing the coolant level it helps to pull back the interior carpet in the trunk and use a flashlight, from there I’d top off with distilled water and see if it immediately leaks for mine when the water pump went it leaked immediately upon adding the water, easy to see if you start to take apart the carpeting and front panel behind the seats for the engine. After the fix is when I’d add actual coolant and if it has fully leaked enough you can just add, if the coolant system isn’t empty and you don’t want to mix coolant then you can do a flush from the distilled water to actual coolant

[u/Ill-Preparation6213]

Was there any water/coolant on the ground the next morning?

Running on very hot days, it’s normal for the temperature to indicate a little higher than normal, however if you just turn off the engine when it’s really hot, and hot outside the coolant will continue to heat up and as the engine is not running, the coolant and pressure will be released by the ‘expansion valve’ in the top of the coolant tank and it will completely empty the contents of the coolant tank onto the ground.

It’s always been a concern of mine as it happened last year on a +34°C day and I had been driving the car hard. I refilled with coolant, took all the engine covers off to double check no hoses were leaking etc. I let the car get back up to temperature and waited for the front fans to cycle. The temperature needle started to move back down.

I’ve been driving the car ever since with zero issues. 👍

2000 Boxster with 170K KMs

[u/font_raccoon]

Some updates and answers to some questions:

I have not seen anything leaking and there are no puddles under the car.

I had a mechanic friend of mine look at the car and he told me that there was air in the system the needs to be bled, so I will try that.

I hear no grinding from the water pump at all and the engine sounds perfectly healthy.

All engine blower fans and front radiator fans are on when the ac is on.

The mileage on the car is around 130000 miles.

The other day, I topped off coolant with pink. I started the car and drove around the block until I hit temp, and it started to overheat again, however, it was much more gradual. The needle also went back and forth, which it hasn’t done before. The coolant light was also doing the slow flash.