Increased radiator blocking in winter.....
 

I have approx 1/2 of my radiator blocked with cardboard...over and above having the top opening blocked and a front pan installed.

I have an LED indicator installed that lets me know when the rad fan runs. Noticed during a warmer spell...60s-70s...that even with the rad 1/2 blocked...the fan only ran a limited amount....indicating maybe blocking by 2/3s or so would be OK.

Have noticed that with my car...I'm seeing almost the same indicated mpg (SG) after the car is well warmed up when temps in the low 30s F as in summer driving.

Wondering about practical and safe methods to increase and keep underhood temps higher?

Block heater? Blanket? Variable rad opening?

This is how a 2012 Focus can get 47 mpg on the freeway on 40F weather?

I use far more grill block in winter than in summer. I wouldn't have it any other way. I use removable bits to adjust it as needed.

With outside temperatures below freezing, the opening on my car is only about 5" x 6". But I have to pay attention, when temperatures rise up into the 40s and 50s I need to reduce the grill block or risk overheating.

Use your scangauge to show engine coolant temperature. I think the display is labeled ºFWT (water temperature). Observe for a few days with your grill block as it is now to see what temperatures it settles in at. Learn what temp your rad fan comes on at. Then when you increase your grill block you'll have a frame of reference.

My own engine settles in around 195ºF in moderate weather, with a 180º thermostat. Last summer with a 172º thermostat it stayed around 182º. If I block the grill too much it goes up over two hundred (still OK in my opinion) and has occasionally gone scary high.

The fan on my Focus starts at 233F and shuts off at 222F. In summer FWT will regularly run over 200F...maybe from ~204F up to 210F? FWT is one of the readings I use all the time.

I'll probably go ahead and cover 2/3s of the rad...I do have the LED indicator mounted right on top of the SG. It's when I see running temps above 200F that I see the good mpg.

I might come up with a grill cover that is easily mountable and that has a sliding panel in it for adjustment....something with clips on it to be easily removed.

It's the "scary high" that you need to worry about...theory being that this weakens the headgasket over time due to too much movement....

I thought of using a very fine screen in front of the radiator, during high speed high load the screen would be fine enough so that turbulence would block a high percentage of the air but if you get too warm or in traffic, plenty will flow due to lower speeds of air hitting the screen. sort of a self limiting flow, as it will max out at a certain speed. no idea if it would work but always wondered about it.

I made a screen for the radiator in my Ford truck. It is made like a screen for a window, same materials. It sits neatly in the recess formed by the tanks and the core, so the screen is very close to the core tubes. My thought was to avoid getting bugs and small debris from clogging the radiator, never gave any thought to it limiting air flow. I guess I should test airflow through the radiator with and without the screen. I need to get the truck running first, though.

Good idea, I though of making the screen cover the grille and shape it so that the faster you go the more would travel over the surface instead of through the screen, easy to form also , first layer could be some hardware cloth shaped the aerodynamic way you want , then layer on some finer screen to control flow to radiator,might be a speed secret nascar guys are already using, or know about

I've had window screen over the front of the radiators with 2 different 4x4s....doesn't seem to hurt airflow much....keeps debris off the rad and it usually it washes off the screen eventually.

I'm talking about a solid cover made out of plastic or plywood that would cover the outside of the intake grill and have a sliding door in it. Some that have totally modded the bodywork on the front have done exactly this...but I would make one that was easily installed and removed....used only in winter and with original bodywork.

I'd probably use some thin plywood since I have some....

You'd only want to mess with this IF you have an LED indicator for an elect fan...since you can get overheating pretty fast when you start blocking air? Can't trust that you'd SEE a regular temp gauge or a SG when you need to???

Removed the cardboard in front of the rad and installed temporary blocking on remaining grill opening...blocking around 2/3s of the opening. On a 40f-50F day I had the fan come on at times when not on the highway....city or lots of stop signs. FWT temps stayed over 200F...with warmup taking less time.

Might work on a more permanent solution involving thin plywood blocking panels.

I don't know about the SG, but my Ultragauge has alarms that flash and have an audible beep when a gauge exceeds a preset limit. You will definately notice when it triggers an alarm.

I have it set for 210°F right now, but I need todrop that down. The fan turns on before then and even 100% blocked off, it never triggers the alarm.

Made up 3 panels to fit to the grill opening using thin plywood with DIY spring clips mounted to the back. Painted flat black.

2 that cover about 1/3 of the opening and one that covers maybe 1/4 or so.

So as temps change I can cover from 1/4 to 1/2 to 2/3s of the remaining grill opening.

The idea being to get FWT temps up as soon as possible and keep them in the 200F to 210F range if possible while driving.