Heater temperature in cold weather
Discussion
Hi. I'm having some challenges getting the heater to throw out hot air when the weather is cold. I'm in Canada and just got the car out after the winter and whilst the days are dry and clear, temperatures are still pretty chilly.....hovering between +5 and- 5C. In these temperatures, the car won't run at much more than 50 and 60C on the highway (according to the temp gauge which i know can be somewhat unreliable), it will sit comfortably at about 60c on the main roads, but it will warm up nicely when idling. The heater works really well when the car is up to temp but its luke warm at best in traffic, and won't push out any warmth at all on a long run. I don't mind the cold and just put a coat on, but passengers don't seem to appreciate the whole experience quite so much especially if there is a perfectly good SUV alternative on the drive what is warm and toasty.
If anyone has any suggestions about what i might try or what might be wrong I'd really appreciate it.
If anyone has any suggestions about what i might try or what might be wrong I'd really appreciate it.
That all sounds about right for the temps you are driving in.
In general here in good old blighty, winter temps will average out at above 0 degrees [most of the time] and these cars will rarely get above 70c during the winter.
You could possibly block off a percentage of the radiator, but this could then be a problem at idle if the car got hot enough for the fans to kick in.
I think its a wooly hat and gloves time, and i do hope you are driving with the roof down, after all that is what these cars are all about.
In general here in good old blighty, winter temps will average out at above 0 degrees [most of the time] and these cars will rarely get above 70c during the winter.
You could possibly block off a percentage of the radiator, but this could then be a problem at idle if the car got hot enough for the fans to kick in.
I think its a wooly hat and gloves time, and i do hope you are driving with the roof down, after all that is what these cars are all about.
this always confuses me my car does exactly the same? to my way of thinking the thermostat shouldn't open until 82deg.c or what ever temp thermostat you have. so the engine should always stay at that temp. unless the radiator is unable to shed the excess heat in which case the temp should rise. there must be something wrong with the plumbing on these cars that allows coolant to bypass the thermostat and make the engine run cooler than the thermostat opening temp? it shouldn't happen.
Cold air enters the front of the car and passes along the space between the inner and outer wings. Wiring, pipework etc are routed into the cabin and if not sealed tightly allow cold air especially at speed to enter the cabin around your knees and feet. Worth checking.
Otherwise, excessive radiator cooling at speed is probably causing it. Try fitting some aluminium cooking foil across the front of the radiator so that it covers around a third of the bottom part and try it. Adjust as required.
Otherwise, excessive radiator cooling at speed is probably causing it. Try fitting some aluminium cooking foil across the front of the radiator so that it covers around a third of the bottom part and try it. Adjust as required.
You need to connect up something to read the temperature that the engine is seeing from the rover temp sender, rather than the gauge TVR connected up. I suspect they will be higher than the dashboard gauge.
The heater matrix is high compared to the waterways in the engine and radiator and can easily get air locks, which lower the potential heat pumped into the cabin.
Then there are the sources of cold air that get into the car from the inner wings and vents along the side of the footwell.
Combine all of those and it can be chilly, plus expensive if the engine runs to cool.
The heater matrix is high compared to the waterways in the engine and radiator and can easily get air locks, which lower the potential heat pumped into the cabin.
Then there are the sources of cold air that get into the car from the inner wings and vents along the side of the footwell.
Combine all of those and it can be chilly, plus expensive if the engine runs to cool.
This might demonstrate why the tvr temp gauge sender is slightly out of the Water flow.
You’ll notice how both the Ecu and RR ( Range Rover) senders are directly in the flow of water.
The tvr gauge one situated undernearth the manifold is subject to intense heat and not particularly accurate so using Rovergauge to asses temp via ecu sender far more accurate.
I’d do this test to see just how hot the water is getting.
You’ll notice how both the Ecu and RR ( Range Rover) senders are directly in the flow of water.
The tvr gauge one situated undernearth the manifold is subject to intense heat and not particularly accurate so using Rovergauge to asses temp via ecu sender far more accurate.
I’d do this test to see just how hot the water is getting.
Some key points to consider:
1. The Chimaera cooling system over cools the engine when the car is moving at speed in low ambient temps
Consider fabricating a rad blind, even a simple piece of cardboard to block the lower third of the radiator will work wonders in cold weather
2. Anyone using their car in the winter should switch the 83 degree thermostat for the far more suitable 88 degree thermostat
This is the thermostat value Range Rovers with the exact same engine ran, remember the function of a thermostat is just to get the coolant up to the optimal temp as soon as possible and hold it within a temp band thus ensuring both the engine and the heater give their best performance.
The optimal temperature being 90 degrees, remember even in the summer running an 83 degree thermostat in an engine designed to hold it's coolant between 85-93 degrees does not mean it'll run any cooler than if you fit an 88 degree thermostat, it'll just take longer to warm up. Assuming the cooling system is in good condition and the fans are working correctly the coolant temp will peak at 93 degrees at idle irrespective of whether you're running an 88 or 83 degree thermostat, even if you ran no thermostat at all the system would still peak at 93 degrees at idle because peak engine coolant temp is governed by the coolant capacity and radiator size not the thermostat.
People who run a 83 degree thermostat in the misguided belief it helps protect against overheating should study how a car's cooling system actually works, all that happens if you run an 83 degree thermostat is the engine takes a little longer to reach its optimum operating temp, heater performance is significantly reduced during the winter months and in the winter if you join a fast moving road too soon during the warm up phase running an 83 degree thermostat will mean the engine may never have a chance to reach its optimal operating temp.
3. Getting all the air out of the system is essential to enjoying a good heater
Air should in theory always find it's way to the highest point in the coolant system, this is why it's useful to fit a bleed valve at the highest point, look closely at the front left of the inlet manifold and you'll find TVR fitted a rubber hose with a bolt stuck in it to block it off, this was a simple way to block a pipe originally intended for the throttle body heater used in Range Rovers that TVR deemed unnessesary on a Chimaera & Griffith. By a happy accident if you pull this hose up vertically the top of it becomes the highest point in the cooling system so makes for an ideal bleed point. While this point gives a really effective bleed unfortunately air can still get trapped in the heater, jacking the front of the car as high as possible so a greater weight of coolant acts on the heater helps a lot to drive out this last bit of trapped air that can significantly reduce heater performance.
4. Improve Coolant Circulation & Flow Around Your Heater Core
I also run a Davies Crag EBP15 electric water pump, I fitted this to ensure my LPG vaporiser always has a good reliable supply of hot coolant flowing around it, as my LPG vaporiser is plumbed into the heater circuit the unexpected knock-on effect has been my heater performance is further improved
http://daviescraig.com.au/product/ebp15-electric-b...
5. In Summary
With all the above elements covered my Chimaera has one of the best heaters of any car I've ever owned, even on the very coldest day I hardly ever have it set more than half way, because above this it simply becomes too hot in the cabin.
1. The Chimaera cooling system over cools the engine when the car is moving at speed in low ambient temps
Consider fabricating a rad blind, even a simple piece of cardboard to block the lower third of the radiator will work wonders in cold weather
2. Anyone using their car in the winter should switch the 83 degree thermostat for the far more suitable 88 degree thermostat
This is the thermostat value Range Rovers with the exact same engine ran, remember the function of a thermostat is just to get the coolant up to the optimal temp as soon as possible and hold it within a temp band thus ensuring both the engine and the heater give their best performance.
The optimal temperature being 90 degrees, remember even in the summer running an 83 degree thermostat in an engine designed to hold it's coolant between 85-93 degrees does not mean it'll run any cooler than if you fit an 88 degree thermostat, it'll just take longer to warm up. Assuming the cooling system is in good condition and the fans are working correctly the coolant temp will peak at 93 degrees at idle irrespective of whether you're running an 88 or 83 degree thermostat, even if you ran no thermostat at all the system would still peak at 93 degrees at idle because peak engine coolant temp is governed by the coolant capacity and radiator size not the thermostat.
People who run a 83 degree thermostat in the misguided belief it helps protect against overheating should study how a car's cooling system actually works, all that happens if you run an 83 degree thermostat is the engine takes a little longer to reach its optimum operating temp, heater performance is significantly reduced during the winter months and in the winter if you join a fast moving road too soon during the warm up phase running an 83 degree thermostat will mean the engine may never have a chance to reach its optimal operating temp.
3. Getting all the air out of the system is essential to enjoying a good heater
Air should in theory always find it's way to the highest point in the coolant system, this is why it's useful to fit a bleed valve at the highest point, look closely at the front left of the inlet manifold and you'll find TVR fitted a rubber hose with a bolt stuck in it to block it off, this was a simple way to block a pipe originally intended for the throttle body heater used in Range Rovers that TVR deemed unnessesary on a Chimaera & Griffith. By a happy accident if you pull this hose up vertically the top of it becomes the highest point in the cooling system so makes for an ideal bleed point. While this point gives a really effective bleed unfortunately air can still get trapped in the heater, jacking the front of the car as high as possible so a greater weight of coolant acts on the heater helps a lot to drive out this last bit of trapped air that can significantly reduce heater performance.
4. Improve Coolant Circulation & Flow Around Your Heater Core
I also run a Davies Crag EBP15 electric water pump, I fitted this to ensure my LPG vaporiser always has a good reliable supply of hot coolant flowing around it, as my LPG vaporiser is plumbed into the heater circuit the unexpected knock-on effect has been my heater performance is further improved
http://daviescraig.com.au/product/ebp15-electric-b...
5. In Summary
- In really cold weather only, use cardboard or better still corrugated plastic to block the lower third of the rad, be sure to remove it when ambient temps rise or you run the very real risk of overheating at idle in the summer or at least making your fans work way harder than is good for them.
- Ditch the 83 degree thermostat most Chimaeras seem to be fitted with and replace with an 88 degree thermostat just as the engine designer intended
- Thoroughly bleed the cooling system ensuring every last pocket of trapped air is driven out of the system remembering the heater is often where bubbles get trapped which will greatly reduce heater performance
- Consider using a Davies Crag EBP15 electric water pump to improve the flow of hot coolant around your heater core
With all the above elements covered my Chimaera has one of the best heaters of any car I've ever owned, even on the very coldest day I hardly ever have it set more than half way, because above this it simply becomes too hot in the cabin.
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