Covering radiator grills in cold weather....

Scania

Scania

Scania

Caporegime
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25 Nov 2004
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On the road....
Just seen an e36 with the front "Kidney" grill covered in foil as you used to see years back on Cortinas & the like.

I'm puzzled as to why people do this, a little incident on the M6 in Cumbria the other night in my truck made me really give it some thought.

DSC00166-1.jpg

Taken earlier in the week, but it gives you an idea as to what I mean....

When it snows, due to the wonderful aerodynamics (!) the front of the truck gets pretty caked up, the gaps you see on the front of the cab are covered by a fine black mesh with holes small enough to trap bugs in the summer & particles of road salt etc in the winter. On this particular occasion, I was travelling south from Carlisle and the temperature around Shap was circa -18 (!), it had snowed on the way up, the truck was pretty caked as per the picture, anyway, I noticed to my surprise my temperature guage (for the engine) was rising rapidly so I pulled into Westmorland services and found the front of the truck covered liberally with a hard coating of ice which had completely blocked the mesh I described earlier.

I'd guess the airflow over the radiatior / intercooler had obviously become restricted hence the cooling issue that had arisen.

So, given said issues, why on earth do people feel the need to cover their radiators in these admittedly harsh conditions?

I chipped away the ice & snow and set off again and the temperature guage returned to its normal position.

Thoughts? :)
 
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Helps the car warm up quicker / helping petrol consumption.

Would be required if the car themostat was broken / stuck open.
I don't see why it should make much difference on a fully working car though. At -25C maybe?
 
I've known owners in the Westfield club slap a bit of card or similar over part of the rad on colder days to stop over cooling.
My van hasn't got up to it's normal operating temp once in the last week.

Ive put a slightly bigger than necessary rad in my Indy as it's primarily going to be a track toy, and the r1 engine is already working harder in a car. So I might make some moveable ducting for normal road driving to keep it at a good operating temp.
 
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I'd guess they'd want their engine to reach optimum temperature faster.

I'd wouldn't block a heat exchanger, i.e. car radiator from the atmospheric temperature and pressures. They're designed to exchange heat in such conditions. But off course, if they get blocked by ice, that's another issue. :)
 
( |-| |2 ][ $;15702163 said:
Helps the car warm up quicker / helping petrol consumption.

Would be required if the car themostat was broken / stuck open.
I don't see why it should make much difference on a fully working car though. At -25C maybe?
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I see your point, but it surprised me greatly that a similar situation gave me overheating issues on a modern truck, designed & built in Sweeden (where it gets pretty cold!) with a perfectly fine thermostat.

Hmm....
 
Depends on the age of the vehicle also. Older cars need a helping hand to get up to the right temperature. My old Landy is designed to run at standstill in a desert driving a dynamo for a military radio - needless to say the cooling system is a bit extreme. The oil barely gets much above luke warm in the summer, so it would definitely require a cover in the winter if I was driving it. Which I'm not, its got no interior heater, but that's another story :)
 
R420LA6X2/4MNA said:
I see your point, but it surprised me greatly that a similar situation gave me overheating issues on a modern truck, designed & built in Sweeden (where it gets pretty cold!) with a perfectly fine thermostat.

Hmm....
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Perhaps yours was totally blocked as opposed to partially? I suspect if it was 50% yours would still work fine?

Either way I'm not suggesting it's a good idea for the UK
 
Well a rad is designed to work in high temps, so in cool temps it can cool the engine too much. Blocking part of the rad will allow the engine to run at a higher temp, oils to run thinner etc making them more efficient, and improving the heater output.

One of my old cars actually came with a slot to put a board in (supplied) to reduce the cooling in winter.
 
Dr Who said:
Well a rad is designed to work in high temps, so in cool temps it can cool the engine too much. Blocking part of the rad will allow the engine to run at a higher temp, oils to run thinner etc making them more efficient, and improving the heater output.

One of my old cars actually came with a slot to put a board in (supplied) to reduce the cooling in winter.
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Yes but on modern cars it shouldn't matter as that's what the themostat is for. The only reason they do it on stuff like ice truckers is to protect the cables / pipes from the ultra cold.
 
They do this on Ice Road Truckers, but it isn't really cold enough to need it here.

Some cars do come with a summer/winter flap like Dr Who mentions so you can blank off part of the grille in cold conditions.
 
I run half a rad blocker all year. Makes the lean burn window much wider. But then my bumper and rad isnt much different to what you find on a Ek9 Civic Type R!

OEM cooling systems are massively oversized for UK climate. If mine was not blocked at 30mph Im not sure the thermostat would even open and the engine still would be cold and I'd have pretty poor cabin heat.

Look at BMW's and Pugs, they all have style design bumper apertures but then in the opening there is black pieces of plastic moulded in that the thermal engineers actually deemed the size required. It usually also ties in with the aero engineers pulling less Cd points into the design, air going up and over the car is far easier than fighting through an engine bay. That with the thermal imporvments is exactly why we are seeing active radiator ducting to shroud the radiator as cold start and light loan running on many cars.

Rememeber most gauges sit at middle between 85 and 100C, so the middle of the gauge is not a same temperature condition.

-5 compared to 25 C ambient is a massive difference when you are hunting for around 88C, especially when you add that AC stuffs more heat to the radiator in hot weather and in cold you suck loads of heat out of the system through the heater matrix. A thermostat is a simple compromise, its not a perfect solution.
 
The e60 5 series (non-Sport models only, for some reason) apparently has flaps behind the grill which close when the engine is cold, so it must be of some benefit.
 
( |-| |2 ][ $;15702246 said:
Perhaps yours was totally blocked as opposed to partially? I suspect if it was 50% yours would still work fine?
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Indeed, it was totally blocked with snow and solid ice that took quite a bit of chipping (with a metal bar!) to loosen.
 
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I know when I smashed my bumper on my s40 (another story, another day) and it was repaired by the garage it was returned with a volvo part that blocks the ducting under the main bumper, still leaving the 'stylised' air ducts on the bonnet open.

If you are doing lots of short journeys when the engine hardly reaches temp in the summer, the engine stands no chance this time of the year. Surely in these circumstances the blocker makes sense?

Fluffy
 
Personally, I can't see the point on a car that has an electric fan. If the engine isn't up to temperature then the thermostat won't open and no cold water will be pumped round the engine, surely? On a car with a mechanical fan driven by the fan belt it'll be blowing ice cold air over the engine, so I can see the point in doing it there.
 
DannyDan said:
The e60 5 series (non-Sport models only, for some reason) apparently has flaps behind the grill which close when the engine is cold, so it must be of some benefit.
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This is part of Efficient Dynamics and is fitted to LCI SE models. Obviously its of benefit but only if you stop, get out, and remove it when the engine is up to temperature otherwise it starts to have the opposite effect.
 
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