atx_cayman

This weekend, I had a Low Coolant Warning pop up during startup on my Cayman, which initially startled me. The first warning indicated that coolant might be low, so I need to monitor the engine temperature. After driving a few feet, another warning popped up saying that coolant must be refilled, and I need to stop driving immediately. I parked, let the car cool off for about 5-6 minutes, and started it back up with no warning. Drove it for about 20 minutes and kept an eye on temps, everything was normal.

I brought the car into the dealer today, and they said the coolant was just slightly low so they topped it off. The passive fault code was cleared, and now all seems to be well. Still not sure why the warning would pop up if the level was just slightly low, or what I could have done to get it low. Ambient temps have been high in Austin this entire summer, but this combined with my driving style still should not have resulted in a loss of coolant.

Also, from my research across Rennlist and other Porsche forums, it looks like certain 2018 718s were impacted by a faulty coolant tank sensor that would trigger this warning. Given that my car is MY2021, this doesn’t seem to be the issue, but just something to note.

Has anyone else experienced this with their GTS 4.0?

UncleDude

I had this on delivery, same errors, and mine was down *a lot*. Poor service from the dealer, and they apologized and gave me a bottle of concentrated coolant.

colnagoG60

FWIW, I had a few coolant issues with my 981GT4. Coolant levels dropped due to issue with reservoir cap not sealing well (known issue). Also had a "check valve" go bad, which threw a "Coolant Fault" dash message. Also, if your car sits for several days, not on a charger, you may get a few errant error messages at next startup. Just things to possibly check should the problem resurface.

dnimi123

add water until the bouncy indicator pops up....

colnagoG60

But do that really, really slowly, as its slow to pop-up, and easy to overfill.

wistful

annoyingly, this just happened to me. 20K miles in.

Southbama

Just be thankful that it was not due to a radiator taking a shot of road debris. Ask me how I know.

atx_cayman

Quick update: I had this happen to me again, just over a year later.

I had the same sequence of warnings appear again last week (first the yellow check coolant level warning, then the red "stop driving immediately"), and after cycling the ignition, it went away. Off to Porsche Austin, and another top off later, the car is back to normal. They told me that if I see the warning continue to come up, I should bring it in again for further diagnostics. I am still perplexed why this is occurring, as the cooling system is closed loop, so I shouldn't need to be topping off so often. Perhaps a finicky (or faulty) sensor?

KINGHURL

Had this happen on my GT4 and they found no issue-but topped it up. They said it was good that i reported it and brought it in as if a coolant issue shows up later(like out of warranty), they'd already have a record. YMMV

Josh_357

I too have had similar instances to this recently. My story.

Sept 2021 had a warning on a startup to stop driving low coolant. Dealer replaced coolant expansion tank. Issue went away, coolant was never low, other than some small amount of top up.
Aug 2023, had the warning come back, it would cycle between no warning, Yellow low coolant warning, and Red stop driving warning. Replaced just the sensor in the expansion tank first, this was my attempt.
Oct 2023, finally got the car back to the dealer, they diagnosed that there were some resistance values out of spec on the Rear Control Module, they replaced the module and no more issues so far.

Visigoth

I had this happen twice last month for the first time. For context, I have a 2020 Spyder with about 15K miles. The first time it scared the crap out of me, and happened within about two minutes of start up. However, it was very cold ambient temp, less than 40 degrees, and my drive was downhill so I figured I would watch the engine temperature like a hawk and baby the engine. After a couple of minutes of warm up the warning went away and everything seemed fine. After a second occurrence just like the first I bought some coolant and topped it off (it was low). No issues since.

Sharm

I have had this happen constantly (the yellow warning only) on my 21 Spyder. Seemed to start when the ambient temperature was cold, like once it was < 40 degrees outside in the am. When I went back out in the afternoon from work, and the ambient temperature was above 45F, no warning. I called my SA and he told me to monitor it and if it keeps coming up to bring it by.

To those who topped up the coolant themselves, what brand and type did you use?

Josh_357

Distilled water, likely needs a few ounces and the capacity is like 6 gallons. The coolant to water mix is likely unaffected.

Scrounger

I had this a couple of weeks ago. Low ambient temp and then disappeared by the end of the street. Spoke to my OPC and they said to top up and keep an eye on it. Up to now it hasn't come back. Coolant should be mixed 50/50 with distilled water and should be of an approved type: Glysantin G40.

Sharm

I ended up taking it to the dealer since I had the day off and I had other minor niggling issues with the car. They said the coolant level was low and they filled it up. Weird because I never once had this issue with my previous 911 GTS. If it comes back I’ll report back.