996.2 GT3 overheated today a lot !!!
Discussion
Travelling through London Town, this afternoon, east to west, on a Friday wasn't a good idea anyway. AC on. Completed work at st. Barts and back out to the hood, so car, had been crawling for best part of an hour, and suddenly the temp needle, starting racing towards the red, then off the scale a and beeper sounded 
Every time I got a clear stretch of road the needle would happily come back to 80/90.
When I got back to the office the fan on the boot lid was working overtime for about 30 mins.
Tonight I checked the rads for debris, nothing blocking them, but gave them a Hoover out and rinse.
Took it for another spin, and everything seemed ok.
Not sure I should chance going the Castle meet on Sunday
Never had this problem with the 993 lol
Any ideas?
Every time I got a clear stretch of road the needle would happily come back to 80/90.
When I got back to the office the fan on the boot lid was working overtime for about 30 mins.
Tonight I checked the rads for debris, nothing blocking them, but gave them a Hoover out and rinse.
Took it for another spin, and everything seemed ok.
Not sure I should chance going the Castle meet on Sunday
Never had this problem with the 993 lol
Any ideas?
alan996 said:
Both ballast resistors gone I bet.
The control the fans coming on and off. Had this happen my c4
Its a cheap fix partswise bit it means taking the bumper pff
Ok, this happened in my 993 too. They just fell apart. They must gone recently, because I've been stuck in traffic before without any problems. The control the fans coming on and off. Had this happen my c4
Its a cheap fix partswise bit it means taking the bumper pff
I had a similar issue (not quite the same) with my 996 and it was discovered that the temp gauge was over-reading compared to the normal display parameters. This may not be the case with yours but search for the thread on "996 hidden codes" to find out how to get the true coolant temp displayed on the climate control display. On mine the fans cut in @ 109 degrees (true reading from climate display) and out again at 106 degrees - I'm told this is fairly standard - the display however never quite reached 100 but would normally be expected to show more than 90. If yours gets over 110 on the climate display and keeps going then try to stop it going any higher, either by getting airflow through the rads or stopping the car.
rallyeman said:
Travelling through London Town, this afternoon, east to west, on a Friday wasn't a good idea anyway. AC on. Completed work at st. Barts and back out to the hood, so car, had been crawling for best part of an hour, and suddenly the temp needle, starting racing towards the red, then off the scale a and beeper sounded
Every time I got a clear stretch of road the needle would happily come back to 80/90.
When I got back to the office the fan on the boot lid was working overtime for about 30 mins.
Tonight I checked the rads for debris, nothing blocking them, but gave them a Hoover out and rinse.
Took it for another spin, and everything seemed ok.
Not sure I should chance going the Castle meet on Sunday
Never had this problem with the 993 lol
Any ideas?
As someone else asked, what is the coolant level? Be sure you really observe the level and not mistakenly think you observe a good level from the stain on the coolant tank. When the engine is cold carefully remove the coolant tank cap and the screen and use a stick or something confirm the level is ok.Every time I got a clear stretch of road the needle would happily come back to 80/90.
When I got back to the office the fan on the boot lid was working overtime for about 30 mins.
Tonight I checked the rads for debris, nothing blocking them, but gave them a Hoover out and rinse.
Took it for another spin, and everything seemed ok.
Not sure I should chance going the Castle meet on Sunday
Never had this problem with the 993 lol
Any ideas?
If it is low there's a leak and you need to find it and fix it then have the cooling system fluid level topped up. The best way is to use a vacuum lift system which ensures the system is refilled with no air pockets.
Now the leak may be the coolant cap. They can leak enough vapor to in about a month of daily use have the coolant tank down enough to turn on the low coolant warning light.
Another common failure is the coolant tank. This can not leak most of the time then leak and let pressure vent under high temp/high pressure operation such as might be encountered in low speed, stop/go driving.
Yet another rather common failure point is the water pump starts to fail and this can let coolant leak out. Also, if this is not caught in time excessive play can develop which can have the close fitting impeller blades making contact with surrounding material (cast alum.) of the engine block and the blades can fracture and the pump still turns but little or no (not enough anyhow) coolant is circulated and the engine overheats.
So you need to check the coolant level, the cap, the tank, and the water pump. The latter requires the car in the air and someone underneath carefully looking with a bright light. At the same time coolant leak sign can be looked for at other places.
I note you report you had the A/C on. Did the A/C start blowing hot air? If so this can be a sign the fans stopped working. (I've driven both of my Porsches with one fan not working and never had any overheating problems, and the A/C worked just fine.)
Until you get this sorted I would not drive the car. The engine can suffer severe damage from a coolant leak that let localized overheating occur. This can result in a head gasket leak or worse. For the sake of an inexpensive coolant cap or a not that expensive coolant tank R&R one could be facing thousands in expensive engine repair.
Rockster said:
I note you report you had the A/C on. Did the A/C start blowing hot air? If so this can be a sign the fans stopped working. (I've driven both of my Porsches with one fan not working and never had any overheating problems, and the A/C worked just fine.)
Until you get this sorted I would not drive the car. The engine can suffer severe damage from a coolant leak that let localized overheating occur. This can result in a head gasket leak or worse. For the sake of an inexpensive coolant cap or a not that expensive coolant tank R&R one could be facing thousands in expensive engine repair.
rallyeman said:
Checked coolant level, spot on.
There is no leak then. That is good news.I can think of two possibilities: There is a coolant flow problem. One test is with the car and engine dead cold start the engine and let it idle and as it does check the hoses to/from the radiators to confirm as the engine heats up and the T-stat opens (should open) coolant flows from the water pump to/through the radiators back the water pump.
If the hoses do not heat up there is a flow problem. A water pump has shed some impellers. The T-stat has failed. A hose is somehow pinched. That's about all I can think of.
Or the other possibility is the overheating was a transitory failure of the coolant temp sensor. It read hot, supplied a signal that was interpreted as hot, but there was no real overheating.
On a related note: Now I have an 02 Boxster. What I have observed over time in monitoring the coolant temperature via the OBD2 port and test equipment is occasionally the temp sensor reading, at least that returned by the engine controller (which has converted this from a voltage level to a digital value), pegs at 215C for at least one sample. The data is sampled only every 5 seconds so the reading could be high for a few seconds. Now I have never seen the temp gage react. But if this spurious high reading persisted for some time... that could explain the gage behavior you noted.
I might mention in real high (116F) ambient temp conditions I have seen the temp gage needle climb quite high though I can't remember how high but it ventured into a region of the temp gage I had never seen it venture into before. The warning light never came on. I admit that when this happened I was quite concerned and turned off the A/C to lessen the heat load that I believed in some way a compromised cooling system had to deal with.
It turned out there was no real problem. The engine survived the episode just fine and has racked up 270K miles total with no apparent ill effects from that high temperature exposure that occurred maybe 200K miles ago.
Since the gage works just fine "most" of the time I attribute this to a marginal or loose electrical connection. I have other info that reinforces this belief but won't relate to you the long, technical and boring details.
What I will say is in the case of your car, I would or could believe a marginal electrical connection could be responsible for the temp sensor reading off the scale and causing the temp gage to shoot up to the point that it could even cause the warning light to come on.
Neil, I've had the temp gauge go to 120 when stuck in a tunnel in Brussels. It creeps slowly up and the aircon stops working around 100. There's only 1 fan on the GT3 (offside iirc). If the temp leapt up quickly, it's more probably a dodgy sensor. It takes quite a long time to heat 22 litres of coolant so sudden big changes in temp are not physically possible assuming the water pump is working.
nxi20 said:
Neil, I've had the temp gauge go to 120 when stuck in a tunnel in Brussels. It creeps slowly up and the aircon stops working around 100. There's only 1 fan on the GT3 (offside iirc). If the temp leapt up quickly, it's more probably a dodgy sensor. It takes quite a long time to heat 22 litres of coolant so sudden big changes in temp are not physically possible assuming the water pump is working.
Nick, this is what happened, the gauge shot up quickly. Almost jumped up in fact. as said you've only one fan and one resistor,the resistor is just for low speed fan but you need to check it along with the relays that activate both the lo and hi speed front fan here' a six minute test:
with a short piece of cable (ends striped) remove the two relays that are on their own in drivers footwell position 19 and 20
(its the bottom row of relays with position's 17 and 18 missing relays 'cause they're for 2 fan Carrera etc.)
with ignition ON:
bridge terminal 87 and 30 on relay socket 19 and the fan should run at SLOW speed
bridge terminal 87 and 30 on relay socket 20 and the fan should run at HIGH speed
That test complete and successful, now need to test the relays themselves:
With a screwdriver, prise the cover off both relays and insert back into 19 and 20
Ignition ON:
with fingers pinch the relay switch together (its the switch that spans terminals 87 and 30)
do both lo and hi speed relays and ascertain their relative fan speed work, do couple of times pinching more gently to encourage a bad connection.
If in any doubt, just renew the relays for few pounds.
with a short piece of cable (ends striped) remove the two relays that are on their own in drivers footwell position 19 and 20
(its the bottom row of relays with position's 17 and 18 missing relays 'cause they're for 2 fan Carrera etc.)
with ignition ON:
bridge terminal 87 and 30 on relay socket 19 and the fan should run at SLOW speed
bridge terminal 87 and 30 on relay socket 20 and the fan should run at HIGH speed
That test complete and successful, now need to test the relays themselves:
With a screwdriver, prise the cover off both relays and insert back into 19 and 20
Ignition ON:
with fingers pinch the relay switch together (its the switch that spans terminals 87 and 30)
do both lo and hi speed relays and ascertain their relative fan speed work, do couple of times pinching more gently to encourage a bad connection.
If in any doubt, just renew the relays for few pounds.
Edited by bobsan on Saturday 7th September 16:07
Back from Classic at the Castle ( best event this year )
No problems to report. Didn't really get stuck in any traffic to be fair, apart from a serious rolling road security train on M11, must've been EU diplomats straight from Stansted, back to report on how we can start bombing Syria
So maybe just a glitch, hopefully it will never come back!
No problems to report. Didn't really get stuck in any traffic to be fair, apart from a serious rolling road security train on M11, must've been EU diplomats straight from Stansted, back to report on how we can start bombing Syria
So maybe just a glitch, hopefully it will never come back!
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