Temperature Warning light

After a 'spirited' drive my Temp warning Light started flashing but the temp guage didn't go above centre (appx 90-100). I've only had the car for a month or so and was obviously concerned. Everything running OK still. I have done a search and read up on previous posts, particularly This one I've just checked the coolant level and it is at max - car had a full service just before I picked it up - oil level is fine too. Having left the car for 1/2 hour I've just started it up and the light is no linger flashing. Is this normal or should I be worried? Thanks

I get the same thing on occasions, after a good thrash. It doesn't happen every time, perhaps once every two or three months. The low water level light (flashing red on the temp gauge) comes on, and only goes off after the car has cooled down. I have spoken to a couple of people who say that theirs does the same, so stopped worrying.

Already have - thanks very much Richard

The Boxster does the same thing if it is driven hard, if that makes you feel better. The plastic tank has a sensitive float sensor. Jeff

It does, thanks Jeff

Gents. Had this probem last year on my 98 996. It is not normal but it is not serious. The problem is in the water tank. I think the guy said it was the level sender, whatever that is, or a very small leak in the tank. A new water tank and a hours labour and the problem was gone. You might notice a small amount of water under the tank in the engine compartment. He said if left unchecked the smaal leak could get worse. Tank was about £120. Hope this helps Andrew

its a design fault on tank if you stop engine and restart it should rid the light if it stays on check coolant level

like Gordon says...I think they redesigned the tank but theres no need to replace it if its not leaking. Its happened to me once or twice but only after a bit of a thrash [ ]

Its just started flashing on my 996 C4 since the temp outside has warmed up. I opened the water tank and let out the gas and the water climbs back up to the normal level. The light has stopped. I just put it down to the Sensor picking up that the level has dropped. Si

The tank is presurised. It's not a good idea to take the cap off when the engine is hot but if you do the water will naturally climb back up, if not overflow since it is boiling hot. If you take the cap off when the engine is fully warmed up you will likely scald yourself and most of the coolent will blow out in seconds! The water level min/max should only be checked with the engine cold. If the engine is hot the water level will go down a little with the cap in place. It's normal to have to top up the coolant level every now and then especially in summer.

I wondered why i woke up with a red face this morning[ ]

My expansion tank is leaking this morning. About 2 litres of coolant is lying in a puddle under the back left tyre. I phoned Northway Porsche who said that 996 expansion tanks crack after a couple of years. He has replaced hundreds!! 2 hours labour and £150 tank. Costs more on a Carrera4...Doh![ ] Simon C4 996

Bummer. But now you have had it fixed you won;t have to worry about it for a while [ ] I had mine replaced about a year ago. The main issue is that the coolent is not easy to fill/bleed without leaving air pockets in the system. Suggest you keep an eye on the coolent level for a while after the new tank has been fitted and don;t be surprised if you have to top it up every now and then......when cool of course.

Just one thing Berny. I haven't had it replaced yet. I was wondering if i could use bath sealant on the crack. Anyone had experience of this cost effective labour saving idea??[8|]

Simon I can emphasise mine's in having it fixed today!!![ ] Still think its a pretty poor show from Porsche that they have this kind of issue - great cars, with a revered reputation for engineering excellence - well ignoring the expansion tanks failing, RMS, ??..... (By comparison my £18k subaru impreza turbo hasn't missed a beat in 150k miles!!! - sure it looks like it styled by a blind man but they could teach Porsche a thing or two about engineering excellence)[ ] Keith

Hi Keith, TOTALL AGREE with you mate. Porsche made $1billion profit and they can't produce a half descent seal for the engine and their expansion tanks crack after expanding. Its a bit much. I feel another poll coming on. RMS 18% of 996 drivers Expansion Tanks ??? (I reckon its even more) Si

Engines blowing up. Gearboxes failing. rust in the A Piller door catch MAF failing Ignition coils cracking Cylinder chamber oil core plugs dropping out ECU's going caput the list goes on.......

I just have one of those feelings that i'm going to get every one of them problems. Bit like a train stopping at every station. I don't won't a Ferrari. Si

carrera4boy IIRC, Porsche are now on their 6th revision of the expansion tank for the 996. They must be experimenting with all those different bath sealants until they find one that works!!! Seriously though, how can a team of highly-paid, so-called top-flight engineers screw up the design of a plastic bottle 6 times in succession.....? What a bunch of w***ers

You all might laugh at my idea of B&Q Bath sealant, but it's been fine today, no leaks and no light flashing. There's a funny sound coming from the radiator though, and i'm missing the screw cap from Bath Sealant. [ ]

From the workshop manual:​ ​ Four functions of the coolant warning light:​ ​ 1. Engine coolant level too low ​ - light flashes slowly (0.5 Hz) ​ ​ 2. Engine compartment temperature too high ​ - light flashes slowly (0.5 Hz) ​ (engine compartment blower might be faulty)​ ​ 3. Engine coolant temperature too high​ - light is lit; pointer on the right ​ ​ 4. Temperature sensor at water outlet faulty ​ - light flashes rapidly (1 Hz); ​ pointer on the right​ ​ Note​ The temperature warning in point three is ​ indicated if the conditions "engine coolant ​ temperature too high" and "engine coolant ​ level too low" are present simultaneously. ​

I had this come on last summer on a really hot day while I was at a traffic light; the temp gauge fell to 0. I pulled by at a fuel pump and checked the coolant level, which was fine, so called Porsche and they said it may be that the sensor itself has failed and told me to either bring it in or get Porsche recovery (RAC) to pick it up. Since it was late Saturday and I could not get the car into Porsche until Monday, so I took it home (slowly as the RAC said it may take up to an hour) and swap the cars (had to spend the evening in our 10 year old reliable Toyota [ ]). Anyway, tried starting the car the next day and everything was fine; the light was gone and the gauge was functioning properly. The OPC mechanic told me that this something happens if there is an air bubble which just sorts itself out while the car is left resting. Haven't had a problem or malfunction since then... I would say leave it overnight (which you would have by now) and see if is back to normal today. All the best.

Mine went through a stage of flashing if I was giving it a hard time. If I turned it off and back on it was fine again. It happened over a week and never since? There is a theory that when hot the pipes etc expand thereby causing the water level to drop triggering the light.Makes sense considering the system is so huge.

Thanks for this. It must be 1 or 2 as it only flashes slowly. I tested the engine compartment fan with a power supply unit and it worked. Whilst the water level reads max when i take the cap off, it may well read lower when the syatem is under pressure. I will keep an eye on it. Many thanks, David

Thanks, could well be an air bubble. Just took it out for a thrashing as it hasn't been out for a fast run for a while. Will keep my fingers crossed. David

Good news....that thrashing seems to have done the trick.[ ] Thanks everyone for your comments. David