I-bus coolant temperature gauge - Page 12

quinlan · 20th July 2009, 11:57

Hi Hans,

Having read this thread I started thinking about the ambient air temperature readout on instrument panel and thought to myself...am I at all interested in knowing the outside air temp? I decided that I wasn't too bothered about it but would be much more interested if it gave me the coolant temp rather than air temp. Not being at all technically minded I asked T-cut about the possibility of switching the inputs of both sensors to the ECU. He suggested I ask you about this because you obviously have an expertise in this area. I was thinking that perhaps the ECU takes the temp it receives from the sensor and than converts it to a digital stream for the instrument panel digital readout, if we fed it the temp from the coolant sensor having swapped the wire in with that of the ambient air temp, would it then send that temp (coolant Temp) to the air temperature readout on the instrument panel?
Someone has probably suggested this before. It all sounds far too easy so I am sure you can give me at least 10 good reasons why my idea is unworkable and nonsensical.
By the way, now that I have found out about the trip reset access to diagnostics, I have been monitoring by coolant temps over the last few days and include the temps here for other members info and would also value your opinion on whether they seem a little low. I have a 1.8 petrol 75. First registered on 4th Jan 2002. On starting the car it rises steadily to around 89 degrees. At 70mph on motorway it seems to go no higher than 91 or 92. It will only rise a little further to about 94 when I am idling at traffic lights. Haven't been stuck in any traffic jams yet so I am not sure how high it would go then.

Parker · 20th July 2009, 12:51

My temperature tends to rise to around 84 degrees at 70 mph motorway speeds but has gone to around 88 degrees but never any higher, though I believe there maybe a thermostat issue here, despite a coolish engine the fuel consumption seems fine at around 36mpg (1.8T).

I'm hoping to get Lates to service the car later in the year & will see what they advise then.

T-Cut · 20th July 2009, 15:14

Quote:

Originally Posted by Parker

My temperature tends to rise to around 84 degrees at 70 mph motorway speeds but has gone to around 88 degrees but never any higher, though I believe there maybe a thermostat issue here, despite a coolish engine the fuel consumption seems fine at around 36mpg (1.8T).

I think with those readings I'd be inclined to replace the PRT. They aren't really low, but they aren't high enough IMO.

TC

magranville · 20th July 2009, 20:32

Being a fellow 1.8 owner (turbo) and an avid temperature monitor, my temperature ranges are as follows:

Driving around town = 95 - 102
Motor way = 92 - 96
Stationary = up to 103/4 before fan kicked in

My temperature has never been higher than 103/4 to date (touch wood etc etc). Does this seem about right?

Marcus

T-Cut · 20th July 2009, 21:44

Quote:

Originally Posted by magranville

Does this seem about right?

Almost exactly my findings. High speed cooling kicks in at 107C and off at about 97C.

TC

slimsi · 28th September 2009, 10:44

I have now had my temp gauge a few weeks and I have some interesting findings, basically when I am on the motorway with the AC on or off the temp is always between 80-90c.

What interests me though is that when in stop start traffic like the queue for the blackwall tunnel with the AC on it will rise to 90 but no further, with the AC off it will raise to 104ish and then drop back into the 90's.

My presumption is that with the AC on the fan runs constantly and keeps the temp down? Anyone else see this?

Simon

Parker · 28th September 2009, 11:03

I run the AC all the time on Auto and the gauge generally reads 84 to 87 on a motorway run, like you it has not gone over 90 with the AC running and when stationary. I did leave the engine running outside the house no AC on and it rose to around 102 (ish) when the fan kicked in and it dropped back.

However some previous posts I have read their temps seem to run a lot higher 95 to 109 (but whether that is with AC on I'm unsure).

I was concerned the engine was perhaps running too cold and not efficient, but I get around 36 - 38 MPG as a rule so that seems fine.

Steffan · 28th September 2009, 16:33

Interested to read about the effect of the A/C on the temperature. I had an appalling 1.5 hour journey around the South Circular yesterday, mostly at walking pace. Being generally paranoid about the coolant temperature, I kept the A/C on, reasoning that this would keep the fan on constant and the temperature down. I was frozen (in shorts and t-shirt) but the car was fine!

T-Cut · 28th September 2009, 17:55

You don't have to freeze! The cooling system will start the fan as and when necessary. Even in a 1.8, there's no need to panic if the coolant level is OK and the fan and pressure cap are functional. In the V6, there's even more legroom (if you see what I mean).

TC

Steffan · 28th September 2009, 18:24

I'm on the 3 speed fan - working last time I checked but with a packet of new motor brushes awaiting fitting!

20th July 2009, 11:57	#111
quinlan Newbie Rover 75 Saloon Join Date: Jul 2009 Location: Sheffield Posts: 19 Thanks: 0 Thanked 0 Times in 0 Posts	Would it be possible to switch sensor inputs? Hi Hans, Having read this thread I started thinking about the ambient air temperature readout on instrument panel and thought to myself...am I at all interested in knowing the outside air temp? I decided that I wasn't too bothered about it but would be much more interested if it gave me the coolant temp rather than air temp. Not being at all technically minded I asked T-cut about the possibility of switching the inputs of both sensors to the ECU. He suggested I ask you about this because you obviously have an expertise in this area. I was thinking that perhaps the ECU takes the temp it receives from the sensor and than converts it to a digital stream for the instrument panel digital readout, if we fed it the temp from the coolant sensor having swapped the wire in with that of the ambient air temp, would it then send that temp (coolant Temp) to the air temperature readout on the instrument panel? Someone has probably suggested this before. It all sounds far too easy so I am sure you can give me at least 10 good reasons why my idea is unworkable and nonsensical. By the way, now that I have found out about the trip reset access to diagnostics, I have been monitoring by coolant temps over the last few days and include the temps here for other members info and would also value your opinion on whether they seem a little low. I have a 1.8 petrol 75. First registered on 4th Jan 2002. On starting the car it rises steadily to around 89 degrees. At 70mph on motorway it seems to go no higher than 91 or 92. It will only rise a little further to about 94 when I am idling at traffic lights. Haven't been stuck in any traffic jams yet so I am not sure how high it would go then. __________________

20th July 2009, 12:51	#112
Parker This is my second home Jaguar XJ 3.0 V6 Auto (X350) & Hyundai Tuscon 2020 Join Date: Oct 2008 Location: Bridgend Posts: 10,342 Thanks: 69 Thanked 559 Times in 356 Posts	My temperature tends to rise to around 84 degrees at 70 mph motorway speeds but has gone to around 88 degrees but never any higher, though I believe there maybe a thermostat issue here, despite a coolish engine the fuel consumption seems fine at around 36mpg (1.8T). I'm hoping to get Lates to service the car later in the year & will see what they advise then. __________________ http://www.the75andztclub.co.uk/foru...a585a72d1c.jpg "The only thing to do with good advice is pass it on. It is never any use to oneself" SOME VERY USEFUL LINKS SIMPLE DOOR MIRROR REPAIR FITTING CROFT DOOR FINISHERS FORUM RULES CLUB SHOP

28th September 2009, 10:44	#116
slimsi Loves to post 2005 Ignition Blue ZT 190 + Join Date: Oct 2008 Location: Whitstable Posts: 315 Thanks: 0 Thanked 0 Times in 0 Posts	I have now had my temp gauge a few weeks and I have some interesting findings, basically when I am on the motorway with the AC on or off the temp is always between 80-90c. What interests me though is that when in stop start traffic like the queue for the blackwall tunnel with the AC on it will rise to 90 but no further, with the AC off it will raise to 104ish and then drop back into the 90's. My presumption is that with the AC on the fan runs constantly and keeps the temp down? Anyone else see this? Simon __________________ Harmony to Symphony Upgrade How To: http://www.the75andztclub.co.uk/foru...ad.php?t=39160 Last edited by slimsi; 28th September 2009 at 10:46..

28th September 2009, 11:03	#117
Parker This is my second home Jaguar XJ 3.0 V6 Auto (X350) & Hyundai Tuscon 2020 Join Date: Oct 2008 Location: Bridgend Posts: 10,342 Thanks: 69 Thanked 559 Times in 356 Posts	I run the AC all the time on Auto and the gauge generally reads 84 to 87 on a motorway run, like you it has not gone over 90 with the AC running and when stationary. I did leave the engine running outside the house no AC on and it rose to around 102 (ish) when the fan kicked in and it dropped back. However some previous posts I have read their temps seem to run a lot higher 95 to 109 (but whether that is with AC on I'm unsure). I was concerned the engine was perhaps running too cold and not efficient, but I get around 36 - 38 MPG as a rule so that seems fine. __________________ http://www.the75andztclub.co.uk/foru...a585a72d1c.jpg "The only thing to do with good advice is pass it on. It is never any use to oneself" SOME VERY USEFUL LINKS SIMPLE DOOR MIRROR REPAIR FITTING CROFT DOOR FINISHERS FORUM RULES CLUB SHOP

20th July 2009, 20:32	#114
magranville Regular poster Rover 75 1.8t Contemporary SE Join Date: Feb 2009 Location: near Plymouth Posts: 59 Thanks: 0 Thanked 0 Times in 0 Posts	Being a fellow 1.8 owner (turbo) and an avid temperature monitor, my temperature ranges are as follows: Driving around town = 95 - 102 Motor way = 92 - 96 Stationary = up to 103/4 before fan kicked in My temperature has never been higher than 103/4 to date (touch wood etc etc). Does this seem about right? Marcus

28th September 2009, 16:33	#118
Steffan Avid contributor Rover 75 Saloon, Conn Join Date: Apr 2009 Location: London Posts: 136 Thanks: 0 Thanked 0 Times in 0 Posts	Interested to read about the effect of the A/C on the temperature. I had an appalling 1.5 hour journey around the South Circular yesterday, mostly at walking pace. Being generally paranoid about the coolant temperature, I kept the A/C on, reasoning that this would keep the fan on constant and the temperature down. I was frozen (in shorts and t-shirt) but the car was fine!

28th September 2009, 17:55	#119
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	You don't have to freeze! The cooling system will start the fan as and when necessary. Even in a 1.8, there's no need to panic if the coolant level is OK and the fan and pressure cap are functional. In the V6, there's even more legroom (if you see what I mean). TC

28th September 2009, 18:24	#120
Steffan Avid contributor Rover 75 Saloon, Conn Join Date: Apr 2009 Location: London Posts: 136 Thanks: 0 Thanked 0 Times in 0 Posts	I'm on the 3 speed fan - working last time I checked but with a packet of new motor brushes awaiting fitting!