Menu toggle

Engine Temperature Warning


PCGB Member
Apologies if this has been raised before, but I could not find any similar thread.

I went for a drive today in my 991.2 Targa GTS and had a thoroughly enjoyable time. All gauges in the car were as normal throughout the drive.

On the way home, I stopped for some petrol and on pulling away after filling up, after a very short distance I got the Engine Temperature warning indicator coming up, asking me to pull over immediately to let the engine cool down. The fans were also going ten to the dozen.

I pulled over and waited a little while and checked the water temperature gauge, which was still showing 118. As I was really not very far from home, I decided to gingerly limp home but after a very short time, I received exactly the same warning, this time with the water temperature gauge showing 125.

I stopped again and left it longer this time. On restarting, it was still showing a high water temperature reading, but then suddenly dropped back to its normal level (90).

This happened a couple of times last year but I put it down then to the very hot temperatures we experienced, but today the temp outside was only 9 degrees, so this was clearly not the issue.

Has anyone else experienced this? I suspect it may be the gauge is sticking rather than an actual temperature problem but I am obviously going to have to have it looked at. Any advice therefore welcome.

Whilst no one responded to this thread, I thought I would update it now that the issue has been diagnosed by my local OPC.

It has been tracked down to coolant leaking from my water pump which has caused there to be some coolant in the vacuum lines, which interfere with the valves under scenarios where the engine has come up to temperature, is stopped for a short time and then started up again. A new water pump and associated parts are going to be fitted under warranty.

In double checking the forum, I realise this is far from an uncommon problem and multiple threads across multiple registers give testimony to underline the fact that without any form of warranty, it is a pretty expensive repair.

Sorry that no one responded to your query Keith. On the other hand many thanks for providing a detailed update which is bound to be of value to someone suffering a similar issue at some future time.
In a similar frame of mind... I received coolant temp warnings on my 991.1 while with no more than 5 miles into my journey, all in circa 30mph traffic, all temps and pressures were as expected and I continued on my circa 10 mile town traffic journey and repeated the process to journey home...all with no issues, other than the warning reappeared.
Booked into my OPC and vacuum operated change over valves (COV`s) were found to be the culprit. It seems one of which may operate some sort of mechanical flap which once the engine has initially come up to temp from cold, then opens to assist cooling...? My GUESS is that perhaps a non opening warm-up flap may be detected, triggering the coolant warning.....? As I was in traffic moving at circa 30mph for most of the time and that the journey time was perhaps 30 mins, same again on the return, despite the dash warning, the water/engine temps/pressures remained as normal..?
OPC diagnosed and replaced a faulty COV and two others which showed signs of possible future failure, one with a crack in the plastic body and the other with a corroded electrical terminal.
Apparently there was a COV design change/upgrade during 991 production and four of the eight COV`s had already been replaced on my car previously, and the replacement of a further three leaving only one of the old type fitted.... I would have paid for the remaining still operational old type COV to be replaced... However as the work was carried out under the extended warranty that I had bought into at the time of purchase, my OPC was working within the guidelines of that warranty system and I only became aware of the remaining original type COV details on picking the car up.... Apparently it is the easiest to replace re access as it is part of the spoiler activation componentry. So to some degree I am driving with my fingers crossed but then spoiler deployment is not top of my priorities given my driving style these days and if it fails it is unlikely to cause a breakdown... !
Geedee, glad to hear your problem was resolved, but it does sound somewhat disappointing that the final COV was not replaced at the same time. I guess it again highlights the strict rules that the Warranty team impose on OPCs Around repairs.

I am glad to report that the repair has been done on my car also and everything is back to normal thankfully. Given it was all carried out under Warranty, it represents one of the only times I have come back from an OPC with £0 indicated on the final bill [:)]
Thanks for reporting back Kj, though it would be interesting when/if you have the time, to know what was the cause of your "overheating" issue..Thanks.
Hi geedee,

My previous post (#2 above) summarised the problem I had, with the root cause being traced to my water pump leaking, which meant that it had to be replaced together with associated parts under warranty.

The engine temperature warning in the end turned out therefore to be only a symptom of this. Coolant had leaked into the vacuum lines, and the valves therefore did not perform as required under certain scenarios, meaning that the engine was in fact overheating (very worryingly!) and the water temperature warning light was coming on quite correctly.

Whilst I am in no way a technical expert, I believe this means that it was actually similar to the problem you reported with your COVs, except that in my case the valves were being interfered with by the coolant leaking, rather than failing themselves.

Hope this clarifies things!

Duh..! Sorry Keith, I did think I had read of your issue in more detail though not at the top of this thread...Thanks for taking the time to repeat the cause, and now cure... Big thumbs up.. (-:
My OPC replaced my water pump on my Targa shortly after purchase as it had a small coolant leak.
Very common issue i'm told. A friend has a 991.2 Targa too and his has been replaced also.

Having read the other posts, I believe it is and as Road Runner has said, it sounds like a pretty common problem across the 718 / 911 water cooled model range.

Thankfully my particular issue was dealt with efficiently by my local OPC without any of the angst that appears to have been the case on the 718 cases quoted. There was never any question that it would not be rectified under Warranty and given this conclusion was reached v quickly led to me to suspect that it is seen quite frequently; hence my original posts.

To keep the information flowing on the subject here's my recent experience a month and 500 miles into 991.2 GTS ownership. Hopefully this will help others but the short version is I seem to have water pump/coolant issues as well.

On two drives the oil temp hit 117 before dropping back to the mid to late 90s. This is just pottering around, not pushing it and in a mixture of normal and sport modes. Sport didn't immediately drop the oil temp as some have reported due to the secondary (?) oil cooler kicking.

I called Porsche Silverstone and they said it was perfectly normal and only when it's over 120 should it become an issue. This didn't sit right with me so I checked the coolant level and saw it was sat right at the minimum level. From maximum to minimum level in 500 miles is not normal so I called the OPC back. When I described it again they asked me to call Porsche assist for an assessment and to recover it back to them if needed. That's all happening tomorrow and I'll update the thread as it progresses. I didn't experience any warning lights but with all the signs that would only have been a matter of time. God bless OPC warranties.
Luckily I noticed a leak before any temperature issues. I have attached two pics of pre and post fix by the OPC.
First pic shows a very small drip starting from the water pump housing. The staining on the steel below indicated it had been there for a while.
Second pic shows the replaced (modified) water pump housing after collecting from the OPC.

Thanks for that. I didn't bother taking the cover off to look as it's pretty clear it's leaking somewhere and the recovery guy just took my word for it after seeing the level himself. It just left on the flatbed so I expect I'll get a call next week.
Now I just need to know how the loan car works as I hoped I'd get one dropped off when it was taken away. Diesel 320 awaits, no doubt :)
Porsche have confirmed the water pump is faulty and will be dropping the engine out to replace it. Hopefully this will be the only issue but also a good reminder why an OPC warranty is such good value. Car back next week.
moneypits said:
On two drives the oil temp hit 117 before dropping back to the mid to late 90s. This is just pottering around, not pushing it and in a mixture of normal and sport modes. Sport didn't immediately drop the oil temp as some have reported due to the secondary (?) oil cooler kicking.

Oil temp hitting 117 or did you mean water temp? 117 in oil temp is a little on the high side but 90 is way too low for normal running however, 117 in water is on the high side and 'should' sit ~90.

Oil temp was high and fluctuating, water was a solid 90 although I’m told the water temp is mostly made up.
I thought that water became steam at 100 degrees, or was I not paying attention in Physics class?

dpoynton said:
I thought that water became steam at 100 degrees, or was I not paying attention in Physics class?


Sorry to say, clearly you weren’t paying attention in Physics. Boiling points of a liquid varies with pressure. In low pressure atmospheres the boiling point is lower i.e. at the top of Mount Everest. The boiling point is higher in high pressure atmospheres. The cooling systems in cars are pressurised by there design, plus also you need to take into the effect of the antifreeze solution that’s added to the water.

hope that helps


Thanks Steve.
I can push a pen well, not so good with engineering, leave that to you guys. [8|]

Seems to be the way it works I‘m happier in the land of numbers & science. It took me all my strength to get a grade in English and as for learning another language I am hopeless ????


Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions


The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.