997.1 Coolant problem - Page 2 - Porsche General - PistonHeads UK

I have a 2007 997.1 C2 Tiptronic. The car has just had all the coolant pipes (front to back) replaced & LTT fitted. On picking the car up, after 5 miles a red light flashed and read Temp. Gauge Failure. I immediately took the car back & they topped up the system with coolant. I got the car home, the next day I checked the coolant level, it was fine. I took the car out & 6 miles down the road the same warning light flashed. I got the car home & phoned an Indy closer to home.. took the car to him, he said it would be an airlock & booked it in. He drained & refilled (vacuum) the system…. £150 by the way. The next day I took the car out.. 8 miles down the road, the temp. gauge failure warning came on again. I got the car home & plugged in my diagnostics tool. TBH I am not too familiar with the tool & the instruction booklet has microscopic font ffs! I will post photos below. If anyone can shed any light on the problem I would be grateful or next stop is OPC ££££££

No idea about the code. But having been where you are: 1. air locks are v common and almost impossible to completely eliminate so be prepared to check and top up over next hundred miles. 2. My next stop would be new reservoir cap if not changed. Not expensive.

Discombobulate said: No idea about the code. But having been where you are: 1. air locks are v common and almost impossible to completely eliminate so be prepared to check and top up over next hundred miles. 2. My next stop would be new reservoir cap if not changed. Not expensive. I’ve had the car almost 7 years… not a problem until they renewed these coolant pipes & fitted LTT. 2nd LTT I’ve had fitted.. had one put in 6 years ago. Coolant level not dropping. It doesn’t seem to be circulating as if a valve may not be working. Cars seems fine up to about 7 miles into journey.

I have just changed the water pump on mine so similar work. With the cabin heater on high (and the AC off) with the blower set to the windscreen, if you just let it idle does it get up to temp and does warm air come out after a few minutes? Does it come up to temperature when you drive it? Also you can turn the wheels on full lock and you should be able to feel warm water in the crossover pipes in the front arches running to the radiators. Does your ODB tool let you view live temperatures? Worth keeping an eye on that as you really don't want to overheat it and the water temp gauge is highly buffered (unlike oil). The air bleeder valve on the coolant tank can be left in the open position and you can drive around if you want to burp air out of the system.

Since the work, the oil temp goes up very slowly, the water temp will go up then after about 7 miles will red light warning starts flashing, needle drops to zero & indicates Temp Guage Failure on Rev Counter display. Coolant in expansion tank barely warm after 10 miles. A bit worried about driving it now. OPC only 5 miles from me, that might have to be the option if my Indy doesn’t know! I will go & check the heater now but won’t be taking car out tonight. Edited by Mariosbt on Tuesday 16th November 16:34

Mariosbt said: The car has just had all the coolant pipes (front to back) replaced & LTT fitted. Have you checked that the replacement thermostat isn't faulty? To me from what you've described if the system is properly bled and you've not got an airlock I'd be suspecting that the part was DOA?

Sublime said: Have you checked that the replacement thermostat isn't faulty? To me from what you've described if the system is properly bled and you've not got an airlock I'd be suspecting that the part was DOA? How would I check the LTT? The heater is blowing warm air onto the screen.

Mariosbt said: How would I check the LTT? You'd need to remove it and drop it in a pan of water that you bring up to boil to see if it actuates. However you'll need to drain some coolant first to do that (and then top back up). That said I'd have hoped the Indy after you took it back the first time would have tested that they'd fixed the problem when they drained and re-filled it. At which point they'd have realised it wasn't working. So next thing is they should have fitted a known working thermostat to rule that out in my opinion.

Sublime said: Mariosbt said: How would I check the LTT? You'd need to remove it and drop it in a pan of water that you bring up to boil to see if it actuates. However you'll need to drain some coolant first to do that (and then top back up). That said I'd have hoped the Indy after you took it back the first time would have tested that they'd fixed the problem when they drained and re-filled it. At which point they'd have realised it wasn't working. So next thing is they should have fitted a known working thermostat to rule that out in my opinion. All The initial work was done 50 miles away. The Indy that drained & refilled the coolant was local. He won’t have checked the thermostat. However this is giving me stuff to build on!

If you're getting warm air in the cabin then water is circulating to the heater matrix at least so your water pump is working. An airlock big enough to stall the whole system seems unlikely given you've just had it vacuum filled so thermostat not opening when it gets up to temp could be a cause. Having just taken my own thermostat off as part of the water pump work I wouldn't recommend it as a casual route of diagnosis though!

Slippydiff said: Mariosbt said: 3.6 C2 Tiptronic S In that case, I'd look into this : Faulty Change Over Valve (COV) Solenoids Symptoms: Exhaust Flap Failure or Heater Shut Off, etc. The vacuum solenoid or change over valve has been an issue on all the 911 chassis. The device is designed to direct engine vacuum to effect a mechanical change when requested to by an electrical control unit e.g. open a vent, change the position of an exhaust flap, redirect hot air from feet to screen etc. Likely systems effected include: 1. Air Cleaner Flap 2. Acoustic Simulator 3. Heater Shut-Off Valve 4. Exhaust Flaps 5. Coolant Shut-Off Valve on Engine Bypass Circuit 6. Tuning Flaps 7. Shut-Off Valve on Heat Exchanger for Gear Wheel Set Oil 8. Shut-Off Valve for Clutch Fluid Heat Exchanger (PDK ONLY) 9. Fuel Tank Vent Valve Porsche has used the COV in many circumstances throughout the 911 chassis, so if you have a failure related to a mechanical device controlled by vacuum, look for a failure in the COV solenoid in the system first. Most recently, the 991 cars have had all of their COV solenoids replaced in a maintenance campaign. Note the comments in the last but one post on here : https://www.renntech.org/topic/36660-coolant-shuto...

Possibly a sensor issue paste image below. http://i849.photobucket.com/albums/ab55/infrasilve...

The guy that did the drain & refill of the coolant system is having a look at the next opportunity. The car won’t be going out in a hurry in this sh!tty weather , so no immediate rush to sort it! I will keep you posted on the outcome.. pretty certain this is not the first time this problem has occurred.

The fault showing is coolant shut off valve, this is for the gearbox coolant control, its at the back of the box, near gearbox mounts. They fail and give same warning, as if engine temp sensor failure. They can opened with diagnostic tester, but may have lost vacuum to the solenoid.

How did the diagnosis go?

olv said: How did the diagnosis go? I have now taken the car to OPC. It is being looked at on Thursday so should know then, car not overheating.. so coolant is circulating I will post results when I hear.

anonymous said: [redacted] That could well be it. Just had PSE removed & Topgear Sports Boxes fitted

I know these are a pain to bleed but the one thing i struggle with is the charge of £150 for a drain and bleed after they drained the coolant in the first place, I wouldn't dream of charging the customer for that.

stevemcs said: I know these are a pain to bleed but the one thing i struggle with is the charge of £150 for a drain and bleed after they drained the coolant in the first place, I wouldn't dream of charging the customer for that. No, it was a different indie that drained it the 2nd time.

Mariosbt said: No, it was a different indie that drained it the 2nd time. Ah, that’s ok then,

stevemcs said: Mariosbt said: No, it was a different indie that drained it the 2nd time. Ah, that’s ok then, I took the car for the initial work (£7000) 50 miles from me. When the warning light came up, suggesting there was a coolant issue, i wasn’t going to drive back 50 miles! So I took the car to a ’ local’ indie someone told me about for his opinion & he said it was probably an air lock. He then drained & refilled the system. 7 miles later .. the warning light reappeared. I text him, he text back saying he would sort it. Never heard from him again. He clearly didn’t know what it was! SO NO.. ITS NOT OK. That’s why the car is now at an OPC. Hopefully they will have the technology to get to the bottom of it.

Got a video from OPC today.. been all over the car like a rash. Pointing out aftermarket parts fitted & telling me the tyres were 6 years old & should be changed .. Porsche guide lines must be different to ministry of transport. Even pointed out the battery wasn’t a Porsche recommended battery.. ffs, it’s been on the car 6 years & never let me down, unlike the original Porsche battery! Still not got to the root of the problem. Waiting for the phone call! Im pretty sure I don’t need them to go under my car with a camera to tell me I have had aftermarket exhaust boxes fitted! A bit like a trip to Quickfit I had once to fix a puncture on a 6 week old escort van. They went all over it trying to find something that made it unroadworthy to get more money out of me! Edited by Mariosbt on Thursday 2nd December 23:35

anonymous said: [redacted] I’ve no idea m8.. giving me stress & headaches now!

Got a call last night from OPC saying that the technician would not continue with the investigation unless I had a genuine Porsche thermostat fitted (£350 ) Only just had the aftermarket LTT fitted about 6 weeks ago (£85) reasonable in my opinion. Technician even complained that I had put none OEM wheel nuts on. That was only because the Porsches wheel nuts had rusted and the alloy radius seats had started to crumble! The aftermarket back boxes I had installed are IMO far better quality than the OEM units Not sure where I stand now. Do I just go back, pay whatever for their inspection costs & bring the car home? £600 road tax is due before I drive it back home …… Edited by Mariosbt on Saturday 4th December 12:40

An OPC is the wrong place for an older car, unless you have a bottomless wallet. What they are saying is not unreasonable; they have specs for the car based on OE values and a LTT will change some of these. I think you’ll be getting a bill from them for looking at the car regardless, but I’d get it out of there. What I don’t understand is why you did not go back to the place that did all the work - 50 miles seems a small inconvenience compared to going to another garage and then to an OPC, paying out more money each time. Having spent 7k with them they might have been inclined to help out gratis, as it seems the problem arose after their work. I also don’t feel you’re being fair to the place that did the bleed, as you say you didn’t hear from them - if they texted saying it would be sorted, then the next message or contact should be from you, to book the car in, etc. A Porsche specialist will be able to read codes and clear the warning - sometimes that’s all that is needed.

pete.g said: An OPC is the wrong place for an older car, unless you have a bottomless wallet. What they are saying is not unreasonable; they have specs for the car based on OE values and a LTT will change some of these. I think you’ll be getting a bill from them for looking at the car regardless, but I’d get it out of there. What I don’t understand is why you did not go back to the place that did all the work - 50 miles seems a small inconvenience compared to going to another garage and then to an OPC, paying out more money each time. Having spent 7k with them they might have been inclined to help out gratis, as it seems the problem arose after their work. I also don’t feel you’re being fair to the place that did the bleed, as you say you didn’t hear from them - if they texted saying it would be sorted, then the next message or contact should be from you, to book the car in, etc. A Porsche specialist will be able to read codes and clear the warning - sometimes that’s all that is needed. I contacted the indie that did the £7K work, told them the problem but they never replied. I have been reluctant to ‘name names’ as yet.. but f*ck me I am close! The 2nd indie who is only 4 miles from me , I didn’t know existed until later. I took the car to him & he pointed out it was almost certainly an air lock. He then drained & refilled.. 8 miles down the road same thing! The car isn’t overheating, so really I can drive it anywhere than can ‘sort her out’ …. Simples

P2181 is a code generated when a mapped temperature isn't reached after a specific run-time/fuel throughput following a cold start That is why your code/fault occurs repeatedly after a 7-8 mile journey. P1656 concerns a solenoid valve for the thermal management. 997.1 has very few for that specific purpose - but, on Tiptronic vehicles, the main one controls the coolant shut-off valve for transmission cooling. The failure of the shut-off valve is generally 'safe' - where the cooling circuit for the transmission remains 'open' and therefore 'cooled'; what that results in is the full flow of coolant around a cold transmission that wicks away the engine temperature while driving - the failure of the circuit (electrically or mechanically) is therefore triggering the P2181 code. The LTT won't help matters if the thermal management components aren't functioning correctly - its' main function being keeping overall temperatures lower for longer. IMO: - The coolant level is not the issue - The chances of an air lock are low - The tiptronic cooler circuit solenoid valve is stuck/burnt out/disconnected Get the solenoid fitment/operation checked and while there check the mechanical shut off valve operation (the internal seal can fail meaning despite correct vacuum application via the solenoid and mechanical operation appearing to open/close - the 'shut-off' function doesn't happen).

Pope said: P2181 is a code generated when a mapped temperature isn't reached after a specific run-time/fuel throughput following a cold start That is why your code/fault occurs repeatedly after a 7-8 mile journey. P1656 concerns a solenoid valve for the thermal management. 997.1 has very few for that specific purpose - but, on Tiptronic vehicles, the main one controls the coolant shut-off valve for transmission cooling. The failure of the shut-off valve is generally 'safe' - where the cooling circuit for the transmission remains 'open' and therefore 'cooled'; what that results in is the full flow of coolant around a cold transmission that wicks away the engine temperature while driving - the failure of the circuit (electrically or mechanically) is therefore triggering the P2181 code. The LTT won't help matters if the thermal management components aren't functioning correctly - its' main function being keeping overall temperatures lower for longer. IMO: - The coolant level is not the issue - The chances of an air lock are low - The tiptronic cooler circuit solenoid valve is stuck/burnt out/disconnected Get the solenoid fitment/operation checked and while there check the mechanical shut off valve operation (the internal seal can fail meaning despite correct vacuum application via the solenoid and mechanical operation appearing to open/close - the 'shut-off' function doesn't happen). Really good of you to share this. One assumes an independent specialist would also be able to interpret these codes.

pete.g said: Really good of you to share this. One assumes an independent specialist would also be able to interpret these codes. If they have access to the manufacturers diagnosis system then I would hope so. The P2181 code takes some thinking; it is very often misdiagnosed as a temp sensor or thermostat issue as the usual suspects are guessed at. With access to datalogging I'd watch the coolant and oil temps from a cold start - coolant should heat quickly to 90C; oil takes longer; if the coolant and oil heat at the same rate it's a sign to look for something amiss.

Any update OP? What did you decide to do?

BertBert said: Any update OP? What did you decide to do? The car is currently in an OPC where they are investigating (£££££) the issue.

Mariosbt said: The car is currently in an OPC where they are investigating (£££££) the issue. If I were you I would copy & paste Pope’s comments to your Service Rep at the OPC. IMO it is worth them working through these suggestions before doing anything else. The right person at the OPC will know what they are doing… Also I do think your original Indie should have taken responsibility and sorted this out - I am not sure I would be going back there…

RJ5560 said: If I were you I would copy & paste Pope’s comments to your Service Rep at the OPC. IMO it is worth them working through these suggestions before doing anything else. The right person at the OPC will know what they are doing… Also I do think your original Indie should have taken responsibility and sorted this out - I am not sure I would be going back there… I have pretty much decided which Indie it will be going to in future. Unfortunately I only found out about them after I had taken the car to OPC. Live & Learn!

Hi Mariosbt, have you managed to find out what the root cause of the problem is?

Yes. The car went from OPC to ‘Unique Porsche’ in Westhoughton, the fella there, Darren, put it on his ramp/lift and immediately spotted something disconnected at the side of the Tiptronic gearbox. He literally had the car sorted in 15 minutes. That’s where it will be going in future. Can highly recommend Unique Porsche for anything 986/987, 996/997. He knows them inside out.

Good result finally; glad you got it sorted.

Great result..!