Temperature issues
Discussion
I was off today and decided what a glorious day to take her out for a spin. Now it has to be said that todays temperature was approximately high 20's/ low 30's. For that reason i thought it was reasonable to put on the a/c. Whilst the a/c works ( and works quite well! ). I found it disturbing that the engine water temperature started to creep up to 117 degrees. Please bear in mind that at this point I was hovering between 4th and 5th gear doing 70 mph on the motorway. I immediately switched off the a/c and had both windows down instead. Within a few minutes the water temperature started to drop to around 100 degrees.
Now my first question is: Do I have a/c that is not fit for purpose? I.E. everytime I go to use it, the water temperature goes through the roof and becomes unusable. Was I panicking for no reason and 117 degrees is ok!! Or do I have a problem. And if so, what needs to be done to sort this issue?
The next problem I encountered today was I noticed the oil temperature when after going for a vigorous run. Crept up to 100 degrees when stationary. Surely this can't be right! It soon dropped to high 80's/ low 90's once I started to move again.
And finally on two separate occasions whilst on this same drive today. On my display panel it informed me that the 'water temperature sensor' had failed. I know that can't be correct because throughout the whole journey I was keeping a close eye on just that. And at no point was I unaware of what the temperatures was.
One final thought. Could all three problems be related in some way?
Cheers John
Now my first question is: Do I have a/c that is not fit for purpose? I.E. everytime I go to use it, the water temperature goes through the roof and becomes unusable. Was I panicking for no reason and 117 degrees is ok!! Or do I have a problem. And if so, what needs to be done to sort this issue?
The next problem I encountered today was I noticed the oil temperature when after going for a vigorous run. Crept up to 100 degrees when stationary. Surely this can't be right! It soon dropped to high 80's/ low 90's once I started to move again.
And finally on two separate occasions whilst on this same drive today. On my display panel it informed me that the 'water temperature sensor' had failed. I know that can't be correct because throughout the whole journey I was keeping a close eye on just that. And at no point was I unaware of what the temperatures was.
One final thought. Could all three problems be related in some way?
Cheers John
Edited by Lone Star on Wednesday 24th August 17:51
There will be much better informed responses soon.
I have not noticed the air-con having any noticeable effect on water temperature but, like you, I would be concerned at a temperature of 117degrees. The only time my water temperature goes high is crawling in traffic and I have been known to open the windows and put the heater on, just in case!! I have never had a reading over 102degrees.
My oil temperature always registers about 20degrees lower than water temperature. I do not know if this is right or wrong but that is what the dash says.
Regarding the water temperature sensor; my dash comes up with that fault code regularly. I have asked Fernhurst on several occasions but every time they assure me "they all do that sir"!
I have not noticed the air-con having any noticeable effect on water temperature but, like you, I would be concerned at a temperature of 117degrees. The only time my water temperature goes high is crawling in traffic and I have been known to open the windows and put the heater on, just in case!! I have never had a reading over 102degrees.
My oil temperature always registers about 20degrees lower than water temperature. I do not know if this is right or wrong but that is what the dash says.
Regarding the water temperature sensor; my dash comes up with that fault code regularly. I have asked Fernhurst on several occasions but every time they assure me "they all do that sir"!
1. I think 117C is too high. I have never seen above 97C on my Sag, even yesterday with the air con on full
2. When hot, the oil temperature is related to the water temperature in that the same coolant is used to cool the oil. In my experience, usually the oil is ~20C cooler than the water when everything is up to temperature, so your findings match that
3. Personally I've never seen a water temperature sensor had failed error (over 4 S6 cars I've owned), so they definitely don't all do that
What could be the reason?
1. Your car is one of those that behaves in this way
2. More likely IMHO is either not enough coolant in the system or the pressure cap isn't holding a high enough pressure
2. When hot, the oil temperature is related to the water temperature in that the same coolant is used to cool the oil. In my experience, usually the oil is ~20C cooler than the water when everything is up to temperature, so your findings match that
3. Personally I've never seen a water temperature sensor had failed error (over 4 S6 cars I've owned), so they definitely don't all do that
What could be the reason?
1. Your car is one of those that behaves in this way
2. More likely IMHO is either not enough coolant in the system or the pressure cap isn't holding a high enough pressure
Mu understanding is that there are two water temp sensors, one appears on your dash and one feeds the ECU which controls your fans. So I think the car might be trying to tell you something when it says water temp sensor fail . What temp is your 1st fan turning on and what temp for both ?
Edited by glow worm on Thursday 25th August 11:15
To be fair Fernhurst have proved to me that on my car the 'System fault code 128 Water Sensor failure' doesn't register in the car's fault history and does not stop the fans operating or the dash registering the water temperature. It really does just seem to be a quirk that once cleared will stay cleared for anything from a few hours to a few weeks!
Mine can occasionally thrown up a temp sensor error when it's really hot, I think it's a case that many do it and it's nothing to worry about.
The overall cooling and engine bay airflow on the T350 is pretty woeful. The 2 front scoops channel air in a very messy way to an upright rad and there is really no vacuum in the engine bay to fully draw it in/the hot air out, the Sag for example has some lovely bonnet slats to help with this.
The air-con rad is also slap bang against the main rad which also doesn't help.
My water temp shoots up about 10-15deg if in traffic with the air con on though which is always a disconcerting thing to see.
The overall cooling and engine bay airflow on the T350 is pretty woeful. The 2 front scoops channel air in a very messy way to an upright rad and there is really no vacuum in the engine bay to fully draw it in/the hot air out, the Sag for example has some lovely bonnet slats to help with this.
The air-con rad is also slap bang against the main rad which also doesn't help.
My water temp shoots up about 10-15deg if in traffic with the air con on though which is always a disconcerting thing to see.
Sorry to jump in OP, but it seems to be the season of the fan! 
I've had a similar problem, last evening whilst I had the car out, the temperature sensor failure warning came up. The gauge showed the temerature to be 110 deg. I could smell the water was hot, but there was no steam.
Taken the car out today, the temperature rose to 110 again. I got out and checked, and, neither fan was running?
I also have another little problem, which I was going to start a thread about, but, I'll mention it on here as it might be linked?
I have lost all control from the internal heater/fan control panel. The lights come on, both buttons operate in thier push function ok, but, it's the rotary functions that don't!?
I've had a similar problem, last evening whilst I had the car out, the temperature sensor failure warning came up. The gauge showed the temerature to be 110 deg. I could smell the water was hot, but there was no steam.
Taken the car out today, the temperature rose to 110 again. I got out and checked, and, neither fan was running?
I also have another little problem, which I was going to start a thread about, but, I'll mention it on here as it might be linked?
I have lost all control from the internal heater/fan control panel. The lights come on, both buttons operate in thier push function ok, but, it's the rotary functions that don't!?
It is not normal for the coolant temperature (or oil for that matter) to get so hot when driving at motorway speeds. After a track session the oil may get hot, and after a long summer's traffic jam with the aircon on the temps might hit 102-105. No more though.
So one of these IMO:
- Your gauges are all over reading
- Your fans are not working (oil temp goes up as oil cools too)
- Your radiator/waterways are blocked
- Your waterpump is not doing its primary job in life
Edited to add: I think the first fan comes on at 93c and the second at 98c. Both should be running quite a lot in this weather.
So one of these IMO:
- Your gauges are all over reading
- Your fans are not working (oil temp goes up as oil cools too)
- Your radiator/waterways are blocked
- Your waterpump is not doing its primary job in life
Edited to add: I think the first fan comes on at 93c and the second at 98c. Both should be running quite a lot in this weather.
Zippee said:
Mine can occasionally thrown up a temp sensor error when it's really hot, I think it's a case that many do it and it's nothing to worry about.
The overall cooling and engine bay airflow on the T350 is pretty woeful. The 2 front scoops channel air in a very messy way to an upright rad and there is really no vacuum in the engine bay to fully draw it in/the hot air out, the Sag for example has some lovely bonnet slats to help with this.
The air-con rad is also slap bang against the main rad which also doesn't help.
My water temp shoots up about 10-15deg if in traffic with the air con on though which is always a disconcerting thing to see.
My old T350T experienced the same. The overall cooling and engine bay airflow on the T350 is pretty woeful. The 2 front scoops channel air in a very messy way to an upright rad and there is really no vacuum in the engine bay to fully draw it in/the hot air out, the Sag for example has some lovely bonnet slats to help with this.
The air-con rad is also slap bang against the main rad which also doesn't help.
My water temp shoots up about 10-15deg if in traffic with the air con on though which is always a disconcerting thing to see.
Powers sell upgrade fans that can help and I have heard some owners either adding slats into or around the nose to help airflow and/or replacing with better coolant.
Tamora doesn't face the same design or flow issues and I never see water temps above 100 on the hottest days (35 degree at Le Mans Classic this year sat in slow or non-moving traffic for 30 mins for example)
Further to my original message. I have now checked the coolant and it all appears to be there. I deliberately ran the car with the a/c on and waited.
The first fan kicked in at 83 degrees and the second fan at 93 degrees. This time however the water temperature sensor fail message did not happen! I kept the car running for 20 minutes. My first fan stayed on constantly (once 83 degrees was reached). And when it got to 93 degrees. The second fan stayed on most of the time. I guess if instead I took her out for a run. The airflow would have helped cool her down and the second fan, perhaps would not have been on as much.
My findings this time doesn't explain what happened to me yesterday. Thanks guys for your input though. I can't help but feel this problem will come back and bite me on the bum when I least want or need it!!!!
The first fan kicked in at 83 degrees and the second fan at 93 degrees. This time however the water temperature sensor fail message did not happen! I kept the car running for 20 minutes. My first fan stayed on constantly (once 83 degrees was reached). And when it got to 93 degrees. The second fan stayed on most of the time. I guess if instead I took her out for a run. The airflow would have helped cool her down and the second fan, perhaps would not have been on as much.
My findings this time doesn't explain what happened to me yesterday. Thanks guys for your input though. I can't help but feel this problem will come back and bite me on the bum when I least want or need it!!!!
Seems a little odd..Std ECU settings are as follows, quoted from Speed Six Diag Help doc
WATER TEMP
Water temperature is measured by the sensor in the metal water pipe underneath the
trim panel in the front of the engine bay.If the ECU detects a fault with this
reading it will substitute a value of 95 degrees C. The engine cooling fans are
controlled by this temperature reading, and are turned on at 92 deg C, off at
88 deg C. Therefore under fault conditions the cooling fans will be turned on.
RAD FAN
This denotes if the ECU has turned on the radiator cooling fans. It does this when the
water temp input is above 92 C fan 1 ,94 C fan 2, or if a fault is present in the water
temp input. ECU pins 6 & 41 are grounded, to turn on the cooling fan relay(s). If the
fans appear turned on by the ECU but do not work, check the relay 1 & 7 has a 12V
supply to pins 85 & 30/51, if it does not, check fuse 1 , 3 and 20.
As I say ..what you see on the dash isn't necessarily what the ECU sees
You could check it by running the Diagnostic S/W either TVRs,EVOOLIs (Windows) or Aides (Android) with the appropriate cable.
WATER TEMP
Water temperature is measured by the sensor in the metal water pipe underneath the
trim panel in the front of the engine bay.If the ECU detects a fault with this
reading it will substitute a value of 95 degrees C. The engine cooling fans are
controlled by this temperature reading, and are turned on at 92 deg C, off at
88 deg C. Therefore under fault conditions the cooling fans will be turned on.
RAD FAN
This denotes if the ECU has turned on the radiator cooling fans. It does this when the
water temp input is above 92 C fan 1 ,94 C fan 2, or if a fault is present in the water
temp input. ECU pins 6 & 41 are grounded, to turn on the cooling fan relay(s). If the
fans appear turned on by the ECU but do not work, check the relay 1 & 7 has a 12V
supply to pins 85 & 30/51, if it does not, check fuse 1 , 3 and 20.
As I say ..what you see on the dash isn't necessarily what the ECU sees
You could check it by running the Diagnostic S/W either TVRs,EVOOLIs (Windows) or Aides (Android) with the appropriate cable.
Edited by glow worm on Thursday 25th August 17:46
Lone Star said:
Further to my original message. I have now checked the coolant and it all appears to be there. I deliberately ran the car with the a/c on and waited.
The first fan kicked in at 83 degrees and the second fan at 93 degrees. This time however the water temperature sensor fail message did not happen! I kept the car running for 20 minutes. My first fan stayed on constantly (once 83 degrees was reached). And when it got to 93 degrees. The second fan stayed on most of the time. I guess if instead I took her out for a run. The airflow would have helped cool her down and the second fan, perhaps would not have been on as much.
My findings this time doesn't explain what happened to me yesterday. Thanks guys for your input though. I can't help but feel this problem will come back and bite me on the bum when I least want or need it!!!!
You still need to take it for a run as a next-steo IMO. Using revs generates more heat, which IF the water pump or radiator are an issue will not be cooled = higher temps than you describe above.The first fan kicked in at 83 degrees and the second fan at 93 degrees. This time however the water temperature sensor fail message did not happen! I kept the car running for 20 minutes. My first fan stayed on constantly (once 83 degrees was reached). And when it got to 93 degrees. The second fan stayed on most of the time. I guess if instead I took her out for a run. The airflow would have helped cool her down and the second fan, perhaps would not have been on as much.
My findings this time doesn't explain what happened to me yesterday. Thanks guys for your input though. I can't help but feel this problem will come back and bite me on the bum when I least want or need it!!!!
maybe a faulty sensor. If you have the diagnostics software, plug the car in and take it up to temperature & see when the fans start, compare the readings off the dash and that shown on the diagnostics tool (which is a different sensor that reads off the ECU). I see an 8-10% difference
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