Anyway to warm up faster?

PistolPete said:
I never knew this, I was under the belief that they were closed until they started to heat up and opened at the rated temp for the engine.
That must mean that cars that have overheated due to a thermostat that was stuck shut has been another fault and that the thermostat I recently replaced on my wifes car is faulty as that was shut when it was cold too.
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They slowly open and close with the temperature gradient. Also the jiggle pin that allows a small amount of water through (and for degas) will drive a current through the water. Partly open obviously will restrict flow so it may cause overheating.

Radiators are massivly effective at cooling air, if the stat opened fully only at 80C as soon as that stat opens you swap 80C water for 10C...... so your heated would go cold and you run the risk of thermally shocking the engine.
 
Jonnycoupe said:
They slowly open and close with the temperature gradient. Also the jiggle pin that allows a small amount of water through (and for degas) will drive a current through the water. Partly open obviously will restrict flow so it may cause overheating.

Radiators are massivly effective at cooling air, if the stat opened fully only at 80C as soon as that stat opens you swap 80C water for 10C...... so your heated would go cold and you run the risk of thermally shocking the engine.
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Yes I understand they don't suddenly open but they open over only a few degree's, most start opening 5c below rated and are fully open at rated.
Also, the amount of water passing through any bypass would be minimal and certainly not enough to effect the engine getting up to temp.

Also, how on earth would you thermally shock the engine?
If you dump lots of 80c water into a little 10c water, the temperature drop is not massive. The first time the stat opens will have the "biggest" drop in temp but that will only be a few degrees. It's not like you are suddenly putting 10c water in an engine at running temp - radiators are not THAT good.

The argument to blocking the rad on the basis of the rad being oversized for UK winter is flawed. Being "oversized" is irreverent, as it would simply mean the stat shuts quicker. On the basis that you have the heaters going in the cabin and drawing heat out of the system is irrelevant, as the stat will just shut quicker.
 
They open and close within a temperature range depending on the car. They come rated at certain temps and this is the temp they start opening (82.c for most Vauxhalls). They are usually rated to be fully open or closed within 15-20.c of this temp.

The jiggle pin fitted on some stats is to allow air to bleed through the stat and prevent a pressure build up and release when the stat opens.
 
PistolPete said:
The first time the stat opens will have the "biggest" drop in temp but that will only be a few degrees. It's not like you are suddenly putting 10c water in an engine at running temp - radiators are not THAT good.

The argument to blocking the rad on the basis of the rad being oversized for UK winter is flawed. Being "oversized" is irreverent, as it would simply mean the stat shuts quicker. On the basis that you have the heaters going in the cabin and drawing heat out of the system is irrelevant, as the stat will just shut quicker.
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THAT good?

Its just been sat overnight at 10C why would the water be anything other than 10C?

Sounds like the warmup profile of that car would have a saw tooth temperature gradient during operation.

They are oversized. You could make it smaller and improve the car aerodynamics and help manage engine temp much better.

Thermally shock an engine.... what do you think a big issue with the Lotus Elise is hence a remote thermostat fix and more changes by Land Rover to try helping the head gasket issue.
 
:confused:

No, you are completely misunderstanding my point.
The water in the rad could quite easily be a any temp much less than 10c if it's been a cold night, but the small amount of water 10c into the rest of the cooling system at 80c will not result in the water dropping more than a few degrees, and the 80c water coming through the rad will not drop to 10c - radiators are not THAT good.


Jonnycoupe said:
Block your radiator, log the ECT and then show me it doesnt warm up faster ;)
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You are on. You are away this weekend but I'll do it on monday.
What is the best software to periodically log the OBD data as the software I have is for live viewing only.


EDIT: Just Googled Lotus Elite remote thermostat fix and I can find nothing - same for Land Rover but I'm not 100% sure what to look for, can you point me at to something so I can take a read??
EDIT 2: Never mind, I found some references to a remote thermostat due to a design flaw where the thermostat is on inlet side of the cooling system and therefore does not work correctly or where people have put PRF thermostats in instead to address the problem. This will not be, and is not, the case with most other cars.
 
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If you block the rad, when the thermostat opens the water flowing through the rad will not be cooled by either airflow or the cooling fans.

Blocking the rad also blocks airflow into the engine bay through the radiator which helps in cooling and removing heat within the engine compartment. The engine will heat up quicker if the rad is blocked especially if this reduces or limits airflow in the engine bay.

Once the engine reaches it's stat opening temp it will be limited on the amount of cooling that can be provided due to the rad being blocked off.
 
Lotus Elise... not Elite.

Radiator in front and light alloy engine with limited cooling in the back originally design for a front engine platform did thermal management no good.

If blocking the radiator doesnt work why are new cars getting active radiator vanes?

Ie Ford Focus, Range Rover. Ah yes, they improve engine warm up and hence emissions.
 
Jonnycoupe said:
If blocking the radiator doesnt work why are new cars getting active radiator vanes?
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Because it can reduce drag:

"Ford's new Active Grille Shutter uses a variable shutter system to blank off the flow of air to the car’s cooling system, and when fully closed can reduce aerodynamic drag by up to six per cent.

Mounted in the grille aperture ahead of the radiator, Ford's Active Grille Shutter features motorised horizontal vanes which can rotate through 90 degrees to block the air flow.

Controlled by the car’s electronic control unit, the vanes can be rotated into 16 different positions – from fully closed to fully open – depending on the amount of cooling air required."

So if cooling is required, the vanes open and the drag saving is lost. If cooling is not required (ie when the thermostat is closed) then the vanes can close and reduce drag.


Also, compare like for like. This is not the same as covering the radiator with a bit of card, this is like covering the front entire front grills of the car so yes, this would decrease startup warming times by staving it of air circulation.
 
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Blocking the rad up is better than not. There is no way it can't help.

Don't get hung up on the detail :p
 
PistolPete said:
BAlso, compare like for like. This is not the same as covering the radiator with a bit of card, this is like covering the front entire front grills of the car so yes, this would decrease startup warming times by staving it of air circulation.
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It is on the Range Rover - on diesel models only.

My car warms up to 90 much quicker with rad blocked.

Amusingly if it hits 91 hit and then I turn the heater from off to 20C, ie heater matrix circulation with 5 seconds the ECT is reading 80.....

The water in the radiator > water in heater matrix. Car now are geting cleverer with heat management though, rotary valves and pumping cooling backwards through the engine to cool the head first to stave off pre ignition. Dual cooling systems aswell so the cabin heater is totally seperate from the main cooling system... funnily enough to improve cabin comfort warm up times as there is less thermal mass to deal with.
 
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PistolPete said:
Yes I understand they don't suddenly open but they open over only a few degree's, most start opening 5c below rated and are fully open at rated.
.
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No, you have missed Jonny's point entirely. A wax thermostat is a proportional temperature regulation device, it's not like the thermostat in your fridge or oven that is either on or off with no middle ground.

The amount it opens depends on how far the coolant temperature is above the rated temperature. With the engine at normal running temperature and with a low ambient temperature the thermostat should be nowhere near fully open.

PistolPete said:
:confused:
EDIT 2: Never mind, I found some references to a remote thermostat due to a design flaw where the thermostat is on inlet side of the cooling system and therefore does not work correctly or where people have put PRF thermostats in instead to address the problem. This will not be, and is not, the case with most other cars.
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Wrong again. The thermostat position was done on purpose to decrease warm up times, and it works ok when the engine is fitted into the front of a small cars with a short coolant circuit. On the mid-engined Elise and MGF the much longer coolant path caused problems with temperature cycling, and in the (heavy)Freelander it caused local overheating if the engine was driven hard from cold. The PRT resolves this with a proper bypass and a pressure relief function so driving the engine hard when cold (which obviously isn't a good idea anyway) will open the 'stat and provide coolant flow.
 
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Dogbreath said:
No, you have missed Jonny's point entirely. A wax thermostat is a proportional temperature regulation device, it's not like the thermostat in your fridge or oven that is either on or off with no middle ground.
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How have I missed the point entirely?? To have done that would have been to suggest that I believed it is like an thermostat in a fridge. I have never said or implied that. The only mistake I have made there was that I believed a thermostat was fully open at it's rated temp, not that it starts to open at it's rated temp and that the spread was around 5c when it is in my car 7c, but could be as much as 10c. :rolleyes:

As for the remote thermostat - I can only go on the limited info I could find as it's not something I'd ever heard of.
 
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