MichaelKlein

I’m not really sure where to turn. Periodically my 991.2 Carrera has overheated, red warning on the dash, I pull over and shut it down. When it first happened, I waited a few minutes, and then restarted. It came back fine – I drove it slowly off the freeway and it was fine again. I put it down to an air pocket or something. That happened once like that.

After it did it twice again, months later, just idling in my garage after a drive for 10mins, I started to get worried what was going on. I took it to the Porsche Newport dealership, thinking it might be the water pump recall issue – instead they told me that my car had already received the newer water pump before, that they checked the lines and there was nothing. They noted that my car was tuned and maybe that was it. My 991.2 has had the Softtronic tune on it for a couple of years now – I mean who doesn’t tune their car?

On the weekend, months later and several drives since the last time, it did it again. My wife and I took it for a 15mi trip to a friend’s house. We stopped for less than 10 mins and turned back to head for home. Almost immediately as we got on the freeway, no more than 1 mi from our friends house, bang, she popped the overheat warning. I pulled it over and waited. But this time there was no coming back. I limped her around the corner to a side street – waited 15-20 mins and tried again. She overheated immediately again, so we called AAA and had her flat trucked home. At no time did the oil temperature ever rise above normal temperatures. Only the cooling system temp.

I have an NT530 so was keen to see what she had registered. While I was checking her, I also idled her for 30mins in the garage (no driving though beforehand) with no issue. I ran a series of tests including the thermal tests on the NT530 which all passed incl the thermostat. Ran the vacuum test which did indicate that the vacuum system was leaking.

In terms of fault codes, there was nothing in the DME, only in the Trans log.

Engine temp too hot: {"ID":0,"DID":"00A004","STAT":"","DDE":"Please refer to vehicle service manual!","HP":false,"FFE":false}

PDK Transmission Emergency Run: {"ID":1,"DID":"00A018","STAT":"","DDE":"Warning: Transmission emergency run","HP":false,"FFE":false}

Doors open or front lid open when driving: {"ID":2,"DID":"00A221","STAT":"","DDE":"Please refer to vehicle service manual!","HP":false,"FFE":false}

I also noticed this in the Gateway log:

{"ID":1,"DID":"000404","STAT":"","DDE":"Current distributor, relay terminal 30SD","HP":false,"FFE":false} - I don't know what this one means

I’m at a loss. It never popped the transmission emergency run message on the dashboard (though I had run a PDK Calibrate some time ago). Nor did it show any kind of transmission overheat, it said engine overheat. I never drove it with doors open or frunk open when driving.

1. What I do know is that the battery is showing signs it’s due for replacement. Could some of this be due to a battery issue?
2. I keep hearing about the crappy vacuum system too - might pull the bumper and see if any are kinked?

What’s the thoughts?

neanicu

Change your thermostat.

MichaelKlein

Can do I guess though the NT530 checked that and it says it passed.

neanicu

I'm not familiar with that test but it probably calculates heating times between sensors until the thermostat is suppose,to open.
Contrary to popular beliefs,the thermostat remains a dumb mechanical device. Sure it evolved into having a heating element which is computer controlled for faster heating times,but it still opens mechanically. Most of the times it gets stuck open and the computer flags the long heating time,but it can get stuck closed as well,at which point I'm not sure that the computer knows...

user 272981109781

Is the linked document correct conceptually?

https://www.tirereview.com/electroni...ake-wax-brass/

I am trying to figure out how else a Porsche 991.2 thermostat can command almost $200.

https://www.porscheatlantaperimeterp...712111000.html

I am not saying this is the thermostat under discussion, just an example.

mangu

sounds like something I had happen on my 991.2 Targa GTS when it was only 11 months old, but I used to get a few more warning lights in addition to the overheat. A thermostat change under warranty fixed the issue.

I was able to replicate it, albeit sometimes, by my usual driving in Sport mode, then while at normal operating temperatures, switching chrono dial to normal/original, and sometimes that would almost instantly trigger the overheat warning.

neanicu

It works like that pretty much...

That's Porsche tax for you!
Save yourself some money by buying OEM BorgWarner wahler,Porsche doesn't make thermostats,BorgWarner does...

https://www.pelicanparts.com/More_In...-121-110-00-M2

MichaelKlein

Ooh thats great! Good deal thanks!

MichaelKlein

Well huh. Thats pretty much what happened on the weekend. Was driving there in Sport mode and when we left for home was in normal driving mode. Looks like it might be the culprit and frankly easier than COV valves

Thankyou!

justbob

Sounds like what I'm going thru. Did you check your water/coolant level?

MichaelKlein

yep and it was fine. When I called the dealer to check whether they had a thermostat they said "yeah, there used to be issues with 991.2's with the water pumps but now were seeing a lot of thermostats dying. That really is likely to be it"

barncobob

just had thermostat replaced by dealer, drove 3 days and it started popping coolant codes, they put another thermostat in and same thing..called and said bubble in system flushed out, supposed to get the car back today..by the way the thermostat only is $248

barncobob

dealer just delivered car back to me. 45 minute drive.Before the driver left i started engine....water 194:} and oil 219...perfect and no codes. might go to car show tomorrow,its washed, windows clean.

barncobob

took it out today to car show, drove the snot out of it....temps are perfect..did have to add 16oz water before leaving home...no leaks showing anywhere..

MichaelKlein

Well I just replaced the thermostat and vacuum filled the coolant (to make sure there was no air pockets) and tested her out. Early days but that seems to have been it - temp has been rock solid, and hammered her a bit to make sure. Probably the easiest part replacement Ive ever done on it lol. Next step will be a longer drive before I call it solved
Also replaced the battery with a 95ah one - the tray takes the larger one. Cranks a lot better, the weird fault codes seem to have also disappeared.
Happy she seems to be fixed - thanks everyone for your advice and tips on where to get the best priced thermostat!