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MLW2233

Blanking Off The Radiator

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In the 'old days' I regularly blanked off about 1/3 to a 1/2 of the radiator area with tin foil on the grill or cardboard in the space between. I have not done it for many years and it might be a good idea now. After all 1 degree now is very different to 28 degrees in August. I know electrics love it cold, so a). Which is the engine radiator space? B). Is a third a reasonable blank off, given there is no temperature guage to assess the situation?

Anyone had success here?

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Hi blocking the radiator will improve the MPG I have done this for the last 6 years and found it to improve the fuel consumption by about 3/4 MPG on the Gen 3 it is the bottem rad and I believe but am not sure (long time since I owned a gen 2) it is the same on the Gen 2 the top rad is to cool the inverter so it is worthwile finding out for sure which is the engine coolant rad .

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Hi blocking the radiator will improve the MPG I have done this for the last 6 years and found it to improve the fuel consumption by about 3/4 MPG on the Gen 3 it is the bottem rad and I believe it is the same on the Gen 2 the top rad is to cool the inverter so it is worthwile finding out for sure which is the engine coolant rad .

HV inverter/motor coolant radiator is located at the bottom for the Gen 2 hence, block upper grill only unless really cold.

According to priuschat the recommendation for the gen2 is as follows:

Partial Blocking

Once the daytime high temperature in your area drops below 50 F degrees (10 C), it is safe to block the upper-grille entirely and the lower-grille partially.

Full Blocking

For those experiencing in harsh climates, such as Minnesota, there can be a benefit from blocking the lower-griller entirely. You’ll want to monitor temperature of the coolant though. Also, note that outside temperature won’t be displayed correctly, since that will inhibit the sensor.

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I had a Gen 3 for three years and blanked off the BOTTOM grill, like the previous post I think the top grill allows air to cool the invertor radiator and should not be blocked off. There was quite a few posts on the Priuschat site which detailed the effects of blanking off different percentages of the grills. Hope this helps... by the way I've blocked off the bottom grill of my CT200.

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A week or two ago I blocked the lower grill completely and left the upper grill open. I found this morning when I returned home after a short run that snow had slid forward off the bonnet and was completely blocking the upper grill as well. Luckily I hadn't been far so no harm done.

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I found this morning when I returned home after a short run that snow had slid forward off the bonnet and was completely blocking the upper grill as well. Luckily I hadn't been far so no harm done.

Top tip: Brush snow off car before driving off. :driving:

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You could once able to buy adjustable radiator blinds.there was a winder you fitted under the dash for adjustment.

Doubt there would be enough room to fit anything like that with modern cars.

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You could once able to buy adjustable radiator blinds.there was a winder you fitted under the dash for adjustment.

Doubt there would be enough room to fit anything like that with modern cars.

The new Focus's come with these now, but automated! Depending on external& engine temperature they open and close by themselves. Do a search for Ford active grille shutters, there's videos of them working, fantastic tech! Would have been great on the hybrids.

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You could once able to buy adjustable radiator blinds.there was a winder you fitted under the dash for adjustment.

Doubt there would be enough room to fit anything like that with modern cars.

The new Focus's come with these now, but automated! Depending on external& engine temperature they open and close by themselves. Do a search for Ford active grille shutters, there's videos of them working, fantastic tech! Would have been great on the hybrids.

Rolls Royce Had this system for many years, but dont know if modern ones have anything like it.

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As there's a new Mondeo hybrid due this year, perhaps active shutters will be on that...

I'll be looking at that car with some interest, as it will have some toys that Toyota don't/won't give us on the Prius.

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Apparently the new Mondeo has been put back to late 2014 'due to closure of Genk factory' (source: Honest John website).

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Bah, that's a shame. But there's also a hybrid Focus planned, and so forth. The market segment will change significantly over the next couple of years I guess.

Incidentally I just noticed price of a Prius C in the States. The equivalent of just under 13k GBP here. Even a Prius Plugin is only 20k GBP equivalent. I know it's not quite as simple as that, but still!

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Rember a friend of mine years ago asked a chap pretty high in Mercedes how they worked out the pricing on their cars in the UK and was told their prices are as hgh as they can get away with.

.

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That's the way most products are priced.

Incidentally, the plug-in Prius in France costs €37,000, almost £3,000 more than the UK price.

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Hi 37000 euros is £31092 aprox, the plug in prius in GB is £33245 less £5000 goverment grant equals £28245 on the road, without the grant £2152 dearer with the grant £2847 cheaper you just do not know how long the grant will last and when it ceases will the price drop, at £28245 it is a dear car at £33245 you have to be mad to buy it.

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The plugin was expected to be around £27k, then the £5000 grant was introduced...

Nissan did the same with the leaf.

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Hi it seem's Toyota are getting greedy and decided to pocket the grant but from my dealings with them having bought new toyota's since 1986 thay do not have any customer care anymore just take your money and run.

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I wasn't there at the time but ISTR Rolls-Royce introducing this in the 1920s.

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There used to be radiator blinds available as accessories. I fitted them to a couple of cars in the early sixties. Overheating (and over-cooling) was a common problem in the old days so many cars had a water temperature gauge (sometimes directly onto the radiator cap and visible through the windscreen) - not to be confused with an Oil temperature gauge. I would be wary of blocking air flow through a radiator without some means of checking the coolant fluid temperature.

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Hi gents ,

I have been following this topic with interest , and I went so far as to block off the lower half of my Auris HSD grille. I did it at work today and then drove home 50 miles. Cant say I really noticed any difference.Then I started to think about it and I can't think how grille blocking can possibly make any meaningful difference to economy.

My reasons are;

When the car is started from cold the thermostat valve in the cooling system prevents the cooled fluid which is in the radiator from circulating so the fluid around the engine is in a closed loop until the fluid reaches a pre-determined temperature(whatever that may be), only then does the thermostat start to allow colder fluid from the radiator to enter the system. So how can blocking the grille speed up warmup time ?

In cold conditions (like now in the UK) when you have an excess of cooling capability-, once the car reaches operating temp the thermostat again will progressively shut if the fluid temperature drops thereby preventing un-necessary heat loss from the engine. So the radiator is not in the loop so once again the grille blocking is doing nothing.

The only time that grille blocking would increase temperatures is when you do not have enough cooling capability then the thermostat will be fully open - taking cooled fluid from the radiator but if the surface area of the radiator is not enough then the temps will continue to rise- but surely that is not something any owner would try to do??

What I have just described is a very simple car cooling system - and I would expect Toyota to have refined and improved it for the hybrid-particularly since heat loss is a form of energy loss which is detrimental to economy,

So what I am missing here ? Please correct me if I am wrong here guys ?

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NB sorry about the blank reply

Hi gents ,

I have been following this topic with interest , and I went so far as to block off the lower half of my Auris HSD grille. I did it at work today and then drove home 50 miles. Cant say I really noticed any difference.Then I started to think about it and I can't think how grille blocking can possibly make any meaningful difference to economy.

My reasons are;

When the car is started from cold the thermostat valve in the cooling system prevents the cooled fluid which is in the radiator from circulating so the fluid around the engine is in a closed loop until the fluid reaches a pre-determined temperature(whatever that may be), only then does the thermostat start to allow colder fluid from the radiator to enter the system. So how can blocking the grille speed up warmup time ?

In cold conditions (like now in the UK) when you have an excess of cooling capability-, once the car reaches operating temp the thermostat again will progressively shut if the fluid temperature drops thereby preventing un-necessary heat loss from the engine. So the radiator is not in the loop so once again the grille blocking is doing nothing.

The only time that grille blocking would increase temperatures is when you do not have enough cooling capability then the thermostat will be fully open - taking cooled fluid from the radiator but if the surface area of the radiator is not enough then the temps will continue to rise- but surely that is not something any owner would try to do??

What I have just described is a very simple car cooling system - and I would expect Toyota to have refined and improved it for the hybrid-particularly since heat loss is a form of energy loss which is detrimental to economy,

So what I am missing here ? Please correct me if I am incorrect here guys ?

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Air also usually passes through a car radiator and therefore could cool anything behind the radiator. The engine block will suffer direct heat loss otherwise how would the engine cool down when the car is parked? I imagine that blocking some of the cold air entering the engine bay would help a little bit.

If I recall correctly Ford has an automatic system for controlling the blocking of a radiator, and truckers in North America block their radiators in winter so I've always assumed that it must have some effect...

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Hi, Blocking the engine cooling radiator allows in winter the engine to operate more efficiently, you'll find it gets up to temperature quicker, allowing engine to shut down earlier in start up process and running on Battery. I did it on my Gen 3 for three winters and certainly believe it improved the MPG by about + 5MPG.

I usually block at strat of cold weather and remove when tempertaures approach 15C in spring - have also block ed radiator on my lexus

A lot of discussion has be said on prius chat, try the following link

http://priuschat.com/threads/2010-prius-grill-blocking-strategy.62556/page-2

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