Another temperature related question....
Discussion
Having reviewed a some previous threads on temperature related queries I'm still unsure if the situation I am experiencing is just paranoia or needs attention - I am erring on the latter.
My Chim 450 (serp engine) has had a new water pump, otter switch, ECU temp sender (original not the Range Rover one yet but am seriously considering getting one as a matter of course); the system has been carefully bled and the fans cut in at about 90c. If I hook up Rovergauge and watch what happens from cold start up it all seems absolutely spot on and within all parameters. Once up to temp the ECU goes into adaptive mode and fans cut in and out keeping the temp pegged between 90-95c. This is all done from cold and just leaving the car in situ idling.
If I then go out for a drive with Rovergauge still hooked up the temps are all fine, reducing to about 85-88 driving at moderate speeds. Once I stop for traffic or get involved in a few miles of 30mph or slower with a bit of stop/start traffic, things start to heat up quicker than I would like/expect. If I sit in traffic idling for about 10 mins the temp is up to 100c and will slowly creep up with the fans running flat out. I turned it off at 103c because I didn't want to risk it any further. I know the heat in the engine bay is ridiculous and airflow when stationary is less than ideal but are short periods at these temps to be expected (it cools down quickly once back on the move)? What is the window of real dangerous temps on these engines?
I also have an issue with my temp gauge which is completely inaccurate compared to the Rovergauge readings and wonder if the Range Rover temp sender is likely to resolve that or if you think I need to do something with the gauge (caerbont gauge).
My view is that I am thinking I might need to replace or re-core the rad as I can't see what else is preventing the fans being able to do their job - just don't know if I am heading down the right path or am worrying unnecessarily.
Your collective wisdom would be greatly appreciated
Cheers
Rick
My Chim 450 (serp engine) has had a new water pump, otter switch, ECU temp sender (original not the Range Rover one yet but am seriously considering getting one as a matter of course); the system has been carefully bled and the fans cut in at about 90c. If I hook up Rovergauge and watch what happens from cold start up it all seems absolutely spot on and within all parameters. Once up to temp the ECU goes into adaptive mode and fans cut in and out keeping the temp pegged between 90-95c. This is all done from cold and just leaving the car in situ idling.
If I then go out for a drive with Rovergauge still hooked up the temps are all fine, reducing to about 85-88 driving at moderate speeds. Once I stop for traffic or get involved in a few miles of 30mph or slower with a bit of stop/start traffic, things start to heat up quicker than I would like/expect. If I sit in traffic idling for about 10 mins the temp is up to 100c and will slowly creep up with the fans running flat out. I turned it off at 103c because I didn't want to risk it any further. I know the heat in the engine bay is ridiculous and airflow when stationary is less than ideal but are short periods at these temps to be expected (it cools down quickly once back on the move)? What is the window of real dangerous temps on these engines?
I also have an issue with my temp gauge which is completely inaccurate compared to the Rovergauge readings and wonder if the Range Rover temp sender is likely to resolve that or if you think I need to do something with the gauge (caerbont gauge).
My view is that I am thinking I might need to replace or re-core the rad as I can't see what else is preventing the fans being able to do their job - just don't know if I am heading down the right path or am worrying unnecessarily.
Your collective wisdom would be greatly appreciated
Cheers
Rick
What you describe is similar to my own expierience. I can say for sure, they do not like to sit in standing traffic on hot sunny days.
The heat build up under the bonnet is ridiculous. Every time i go for a blast as soon as i am back home on the drive, i open the bonnet
to aid heat dispersion.
I had the smallest pin hole in the radiator, which was invisible apart from a tiny little wet patch under the rad.
I had the radiator recored and now have no problems. New rad cores are more efficient.
For my own piece of mind, i have fitted an overide swith to the fans. As soon as i hit standing traffic i switch the fans on.
I sometimes forget, but no problem as soon as they come on automatically i turn on the overide so the fans stay on, until i am on
the move again.
I just used to get nervous looking at the temp gauge rising. Now i have no worries what so ever. Never seen the temp over 95, even
in heavy traffic on the hottest days.
The heat build up under the bonnet is ridiculous. Every time i go for a blast as soon as i am back home on the drive, i open the bonnet
to aid heat dispersion.
I had the smallest pin hole in the radiator, which was invisible apart from a tiny little wet patch under the rad.
I had the radiator recored and now have no problems. New rad cores are more efficient.
For my own piece of mind, i have fitted an overide swith to the fans. As soon as i hit standing traffic i switch the fans on.
I sometimes forget, but no problem as soon as they come on automatically i turn on the overide so the fans stay on, until i am on
the move again.
I just used to get nervous looking at the temp gauge rising. Now i have no worries what so ever. Never seen the temp over 95, even
in heavy traffic on the hottest days.
Edited by TJC46 on Tuesday 16th July 12:24
The cooling system is pressurised.
Water in a kettle on Everest boils below 70 degrees C and makes lousy tea. Air pressure is well below 15 psi
Water in a kettle at sea level, therefore at 15 psi, boils at 100 degrees C.
A car cooling system is pressurised and runs at 15 psi plus a further 10-15 psi. So the water in it boils at.....?
Water in a kettle on Everest boils below 70 degrees C and makes lousy tea. Air pressure is well below 15 psi
Water in a kettle at sea level, therefore at 15 psi, boils at 100 degrees C.
A car cooling system is pressurised and runs at 15 psi plus a further 10-15 psi. So the water in it boils at.....?
Have you checked your thermostat is opening properly? There is the take it out method and bring it to the boil in a pan or the less scientific but easier hand on top hose and feel the quick change from cool to very hot around the time it’s gets hot under there.
Personally, I view the temperature gauge as an indicator of normal behaviour, rather than an accurate device. I have connected the gauge with a variable resistor to the Range Rover sender and set the resistance to give an answer at the gauge of 90 when all up to temperature and it just sits there even when it is pumping out big heat in the traffic/sun. At that point it was the same as the other sender but it warms up quicker now and isn’t affected that much on cold days in winter or long drives down the motorway.
Personally, I view the temperature gauge as an indicator of normal behaviour, rather than an accurate device. I have connected the gauge with a variable resistor to the Range Rover sender and set the resistance to give an answer at the gauge of 90 when all up to temperature and it just sits there even when it is pumping out big heat in the traffic/sun. At that point it was the same as the other sender but it warms up quicker now and isn’t affected that much on cold days in winter or long drives down the motorway.
QBee said:
The cooling system is pressurised.
Water in a kettle on Everest boils below 70 degrees C and makes lousy tea. Air pressure is well below 15 psi
Water in a kettle at sea level, therefore at 15 psi, boils at 100 degrees C.
A car cooling system is pressurised and runs at 15 psi plus a further 10-15 psi. So the water in it boils at.....?
Over 100 degrees C (probably about 120 degrees C) - now the science lesson is over what am I supposed to conclude from this and how does it help me understand if I have a problem or not? I keep reading that anything over 100 degrees C is cause for concern due to potential liner or warped head issues so are you saying that there's nothing to worry about until the water approaches boiling point - if so it would seem contradictory to the perceptions gained from other sources but I am here to learn hence the query Water in a kettle on Everest boils below 70 degrees C and makes lousy tea. Air pressure is well below 15 psi
Water in a kettle at sea level, therefore at 15 psi, boils at 100 degrees C.
A car cooling system is pressurised and runs at 15 psi plus a further 10-15 psi. So the water in it boils at.....?
I have fitted the alternative temp sender into the redundant Range Rover temp sender hole on top of the engine (just in front of the number 1 injector).
It works perfectly, my Caerbont gauge now reads exactly as you would expect it would, and I have an oil temperature gauge too as back up and the two correlate.
The part number and the sockets required are here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Don't panic - yes, your TVR sender is a spade connector and yes, the RR one is round, but the new sender comes with a spade connection.
The TVR sender is a little way down the front of the engine, so about 4 inches from the RR sender. You don't remove it, you just need the wire off it.
It works perfectly, my Caerbont gauge now reads exactly as you would expect it would, and I have an oil temperature gauge too as back up and the two correlate.
The part number and the sockets required are here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
Don't panic - yes, your TVR sender is a spade connector and yes, the RR one is round, but the new sender comes with a spade connection.
The TVR sender is a little way down the front of the engine, so about 4 inches from the RR sender. You don't remove it, you just need the wire off it.
Great, thanks. Now I have located the correct TVR sender position (I thought it was the ECU sender that gave the gauge reading too) I can replace the Rover one and fit the wire no problem.
Also been looking at my rad and have just seen a small damp patch on the bodywork by the very bottom corner that can only have been created by a small leak in the rad. I think that a recent top up of the water in the expansion tank that I thought had been necessitated as a result of air bleeding through might actually be as a result of a leak! Time for closer examination as that would potentially explain the issue
Cheers
Rick
Also been looking at my rad and have just seen a small damp patch on the bodywork by the very bottom corner that can only have been created by a small leak in the rad. I think that a recent top up of the water in the expansion tank that I thought had been necessitated as a result of air bleeding through might actually be as a result of a leak! Time for closer examination as that would potentially explain the issue
Cheers
Rick
Last Monday I did 180 miles in my recently acquired daily Saab, no problems.
Got to a 400 yard queue for a roundabout, less than three minutes, next thing I knew the dashboard warning was bonging and the temperature gauge was off the scale.
Stopped and let it cool, but the rest of the way home (10 miles) the gauge was flying up and down like a bride's nightie.
Long story short, my excellent mechanic flushed the system and diagnosed it as chunks of radweld or similar in the radiator and heater matrix, clogging up the circulation. Cleaned it all out and had it sitting, running, behaving itself for a couple of hours before he gave it back to me.
All well now with the water temperature, though by coincidence (or not) the turbo bearing gave up (well before it was due) the next day after he had fixed the cooling - new turbo, pipes etc, new wallet.
So blockages in the rad and matrix can cause unexpected temperature variations.
Got to a 400 yard queue for a roundabout, less than three minutes, next thing I knew the dashboard warning was bonging and the temperature gauge was off the scale.
Stopped and let it cool, but the rest of the way home (10 miles) the gauge was flying up and down like a bride's nightie.
Long story short, my excellent mechanic flushed the system and diagnosed it as chunks of radweld or similar in the radiator and heater matrix, clogging up the circulation. Cleaned it all out and had it sitting, running, behaving itself for a couple of hours before he gave it back to me.
All well now with the water temperature, though by coincidence (or not) the turbo bearing gave up (well before it was due) the next day after he had fixed the cooling - new turbo, pipes etc, new wallet.
So blockages in the rad and matrix can cause unexpected temperature variations.
Hi, even though I own a different TVR model I believe I can lend some advise. I purchased a new 1984 TVR Tasmin 280i which had my eyes on the temperature gauge more then the windshield. After blowing head gaskets and trusting the mechanics Solutions which never happened. Finally 2 years ago my new mechanic suggested an aluminum radiator along with the auxiliary fans I always had. I now drive in very hot weather and the temperature gauge run normally at 90 in traffic and lower on highway. If you do not have an aluminum radiator do not let anyone talk you out of putting one in. Unless you have one now! Hope to hear back from you!
Edited by Tasmintvr on Wednesday 17th July 15:52
In all fairness a stock rad with a healthy core will do a similar job 
an often overlooked component is the the cooling system until there are issues a combination of lack of service and s
te quality coolants IMO generally , its how the Hillman Imp and Triumph Stag won the medal for over-heating when it was not a vehicle design fault but poor maintenance , once the core furrs up internally its hard to shift unless you use nasty acids etc not recommended .... new core time 
an often overlooked component is the the cooling system until there are issues a combination of lack of service and ste quality coolants IMO generally , its how the Hillman Imp and Triumph Stag won the medal for over-heating when it was not a vehicle design fault but poor maintenance , once the core furrs up internally its hard to shift unless you use nasty acids etc not recommended .... new core time To answer your limits question- I believe the liners are fitted to the block that preheated to about 120'c to make it expand, and then the liners are clamped as the block cools. This shows you dont have a huge margin for overheating before the liners become loose and trash the engine. Another trick to reduce the under bonnet temperature is to remove the ported vacuum that controls the ignition timing. The problem is the timing is set deliberately late at idle , so the mixture is still burning as it leaves the exhaust port to clean up the emissions, and in the process heats the catalyst and engine bay. Check out COGs input here:
https://www.pistonheads.com/gassing/topic.asp?h=0&...
https://www.pistonheads.com/gassing/topic.asp?h=0&...
This may help...
I recently fitted a 'front splitter' to my chim which was purchased from Ebay. Essentially just a 45 degree piece of aluminium hanging from underneath the front nose to redistribute the air flow. This was to reduce the amount of 'bonnet lift' at high speed. This not only reduced the bonnet lift but I saw a 5-10 degree temperature reduction when driving at low speeds.
Regards,
I recently fitted a 'front splitter' to my chim which was purchased from Ebay. Essentially just a 45 degree piece of aluminium hanging from underneath the front nose to redistribute the air flow. This was to reduce the amount of 'bonnet lift' at high speed. This not only reduced the bonnet lift but I saw a 5-10 degree temperature reduction when driving at low speeds.
Regards,
Thanks all for the replies - going to get a new rad I think as it will be most obvious fix (alongside installing the Rover temp sender for more accurate monitoring). It seems to have the original still fitted so a worthwhile fix in any case. Have considered a recore but am happy to plump for a complete new one even though it is a higher outlay.Will report back once purchased and installed.
Tasmintvr said:
Hi, even though I own a different TVR model I believe I can lend some advise. I purchased a new 1984 TVR Tasmin 280i which had my eyes on the temperature gauge more then the windshield. After blowing head gaskets and trusting the mechanics Solutions which never happened. Finally 2 years ago my new mechanic suggested an aluminum radiator along with the auxiliary fans I always had. I now drive in very hot weather and the temperature gauge run normally at 90 in traffic and lower on highway. If you do not have an aluminum radiator do not let anyone talk you out of putting one in. Unless you have one now! Hope to hear back from you!
Good point well made, but as made by the geezer after you, a new radiator won't have all the accumulated Trump pronouncements of the previous 30 years clogging up its arteries (I don't like to say "sEdited by Tasmintvr on Wednesday 17th July 15:52
t" on Pistonheads")Just been looking closer into the potential leak and noticed that the fans are rotating in opposite directions so one is pulling air in through the rad from the front and the other is pushing it from the engine bay into the rad!!!!! I will be amazed if that is correct operation but wanted to sanity check before sorting it - which I have no idea how to do - any ideas?
Is it just a case of swapping over the two wires in the connecting block for the fan that is going the wrong way (pushing from the engine bay into the rad)? Do they work like that (ie change of polarity type scenario) or are they pos/neg so that won't work? Both fans are installed in the same orientation regards the blade pitch so I just need to get it spinning counter-clockwise rather than the current clockwise rotation.
Is it just a case of swapping over the two wires in the connecting block for the fan that is going the wrong way (pushing from the engine bay into the rad)? Do they work like that (ie change of polarity type scenario) or are they pos/neg so that won't work? Both fans are installed in the same orientation regards the blade pitch so I just need to get it spinning counter-clockwise rather than the current clockwise rotation.
Answered my own question, swapped the wires and it works perfectly Fans cut in and out keeping the temp between 92 and 86. Previously they just stayed on once they had kicked in and now I understand why - one fan was just blowing the hot engine bay air onto the rad so it didn't stand a chance of cooling it down.
Just got to determine if I do actually have a leak but at least while it is full of coolant it maintains temps correctly - yay
Fans cut in and out keeping the temp between 92 and 86. Previously they just stayed on once they had kicked in and now I understand why - one fan was just blowing the hot engine bay air onto the rad so it didn't stand a chance of cooling it down.Just got to determine if I do actually have a leak but at least while it is full of coolant it maintains temps correctly - yay
Well that is definitely one fault discovered, hopefully the only one but time will tell. Good luck.
For anyone else with similar issues, there are two points I'll contribute. First, when I mistakenly thought I had a rad leak just prior to a long trip in my Griffith, I spoke to TVR Parts and their new (copper) radiator was cheaper than the re-core prices I got from specialists. Something to do with manufacturing them in a country with cheaper labour.
The second point was from many years ago when I was 17 and had my first car, a rear-engined Fiat 850 Sport (don't laugh too loudly). After several attempts to locate the cause of overheating, I decided it must be the radiator that was at fault. I tried flushing with radiator cleaner chemicals, also backflushing with hose pressure. The radiator flowed nicely after that. Still had the overheating problem though. Eventually I removed the rad and unsoldered the top tank with a blowlamp. I couldn't believe the amount of crud piled up on the top of the core. The rad had a three-row matrix, but only the centre 4 inches (which you could mostly see previously through the filler neck) was clear and flowing. All the rest of the matrix to both sides had a mountain of crud blocking the flow. Little wonder it overheated.
After cleaning all the core with bits of wire and resoldering the top tank back on, the car ran nice and cool for years. So be aware, even if you get good flow through the rad, it might only be a small part of the rad that is clear.
For anyone else with similar issues, there are two points I'll contribute. First, when I mistakenly thought I had a rad leak just prior to a long trip in my Griffith, I spoke to TVR Parts and their new (copper) radiator was cheaper than the re-core prices I got from specialists. Something to do with manufacturing them in a country with cheaper labour.
The second point was from many years ago when I was 17 and had my first car, a rear-engined Fiat 850 Sport (don't laugh too loudly). After several attempts to locate the cause of overheating, I decided it must be the radiator that was at fault. I tried flushing with radiator cleaner chemicals, also backflushing with hose pressure. The radiator flowed nicely after that. Still had the overheating problem though. Eventually I removed the rad and unsoldered the top tank with a blowlamp. I couldn't believe the amount of crud piled up on the top of the core. The rad had a three-row matrix, but only the centre 4 inches (which you could mostly see previously through the filler neck) was clear and flowing. All the rest of the matrix to both sides had a mountain of crud blocking the flow. Little wonder it overheated.
After cleaning all the core with bits of wire and resoldering the top tank back on, the car ran nice and cool for years. So be aware, even if you get good flow through the rad, it might only be a small part of the rad that is clear.
Borrow a thermal imaging camera and use that to see if there are any cool spots on the rad. If you don't have a mate with a thermal imaging camera, then you aren't a big enough nerd.
Seriously, a laser thermometer might do at a push - point it at various parts of the core to see if there is anything odd in the way the heat is distributed.
Seriously, a laser thermometer might do at a push - point it at various parts of the core to see if there is anything odd in the way the heat is distributed.
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