Air flow around radiator,,, physics question

Messages
109
Location
Arizona
Just got a 2013 suburban.
I noticed the sides of the radiator had rubber flaps(air dams?) that have deteriorated and are not in place. This creates a gap about 4" wide and 14"tall at each side of the radiator. Thus allowing some air to enter engine compartment at the sides of and not through the radiator.
Physics Question:
Will this "bypassed" air increase engine bay temps? Will it reduce A/C cooling? What is the effects of driving, vs. Idling?

Vehicle has factory electric fans.

Do I need yo buy these ASAP? Or is it a non issue?
Thanks for the help
~C
 
Messages
26,136
Location
MA, Mittelfranken.de
I cant tell you the engineering aspects of this but I like to keep it simple. If the manufacturer thought they were important enough to spend the few pennies ea they cost on the vehicle then they had a reason for being there.
It would be rare to see the manufacturer spend and extra 10c on something that cannot be seen by the user they didn't need to.
 
Messages
7,070
Location
Los Gatos, CA
Air flow across the radiator is critical, especially at idle and around town.
I would replace the worn pieces if you see any overheating issues.
Like Trav pointed out, the General did not add cost to its vehicles for fun...
Good luck.
 

Cmobile

Thread starter
Messages
109
Location
Arizona
Thanks, yes I figured they were definately there for a reason. And certainly plan on replacing them,,,at some point in the near future. Found them on a gm parts website. I think they were about $30 per side.

But am hoping to understand how it might affect engine bay temps, or AC cooling from an engineering standpoint. (Just curious)

Engine temps steady at 210, trans at 170-180, so I dont think it's enough to strain the cooling system.

Just replaced a 2 year old AGM battery that died, wouldn't hold charge. So I want to insulate the battery. As part of this project, I suspect these radiator side deflectors would come into play,,, somehow.

Thanks
 
Messages
4,970
I think I found a pic to help you out.

10166d1501526223-cooling-package-trans%2520cooler_zpsmxky0lnj.jpg
 

LvR

Messages
109
Location
SA
What the guys said so far(y)

Engine bay in general may actually run cooler without those flap as long as the electric fans are not running and the vehicle is moving along at speed .................... imo as soon as the fans come on you may have a situation where in slow or stop start traffic you start "recycling" some very hot air through the radiator sourced from under the hood itself because of the absence of the flaps able to prevent exactly this
 

MolaKule

Staff member
Messages
21,950
Location
Iowegia - USA
If I am picturing this strip correctly, this strip is between the fan(s) and the radiator.

If so it is to keep the air flow directed through the radiator and not allow side leakage which would reduce the airflow directed into and through the radiator.

But am hoping to understand how it might affect engine bay temps, or AC cooling from an engineering standpoint. (Just curious)

I would think that if you have side leakage your A/C coils may not get the cooling air flow needed and the A/C efficiency would drop.
 
Last edited:

LvR

Messages
109
Location
SA
If I am picturing this strip correctly, this strip is between the fan(s) and the radiator.

If so it is to keep the air flow directed through the radiator and not allow side leakage which would reduce the airflow directed into and through the radiator.

But am hoping to understand how it might affect engine bay temps, or AC cooling from an engineering standpoint. (Just curious)

I would think that if you have side leakage your A/C coils may not get the cooling air flow needed and the A/C efficiency would drop.

and
" I noticed the sides of the radiator had rubber flaps(air dams?) that have deteriorated and are not in place. This creates a gap about 4" wide and 14"tall at each side of the radiator. "


See the plastic/rubber flap in the pic on the front RH side of the radiator ..................my comment refers to THAT flap going awol - fresh air entering the engine bay without passing though the radiator assembly will have a lower temp than normal - thus engine bay "cooler" as a whole because you are also not removing as much heat from the radiator assembly and sticking THAT into the engine bay.........
 

Cmobile

Thread starter
Messages
109
Location
Arizona
In the pic, it is the rubber flaps directly behind the yellow words and on the other side under the orange tote sitting on top bay. Not between fans and radiator.

At speed lower temps, idle/slow moving, higher temps.?.
 

LvR

Messages
109
Location
SA
In the pic, it is the rubber flaps directly behind the yellow words and on the other side under the orange tote sitting on top bay. Not between fans and radiator.

At speed lower temps, idle/slow moving, higher temps.?.
That's what I am talking about yes and as I explained my logic its not a constant result - its speed dependent.
 

Cmobile

Thread starter
Messages
109
Location
Arizona
Thanks for all the help!
It appears Ford and GM had the same cheap material for those. Many people are taking a neoprene rubber sheet and making their own. I'll follow suit and make my own. "One-n-Done" to quote Gummout.
 
Let’s see. With the truck stationary the flaps are closed to make sure all the air transfers through the radiator to help cooling at load speed or stop and go city driving. At higher speed they are pushed open by the air pressure in front of the truck to lower wind resistance?
 

LvR

Messages
109
Location
SA
Let’s see. With the truck stationary the flaps are closed to make sure all the air transfers through the radiator to help cooling at load speed or stop and go city driving. At higher speed they are pushed open by the air pressure in front of the truck to lower wind resistance?
I see the presence off the flaps as a cheap-ass way to complete a body panel to fit the radiator ....................perhaps I am wrong?
 
Messages
153
Location
Ontario, Canada
I had similar pieces made of foam on my Xterra, with a smaller gap to fill. I replaced the missing ones and noticed a definite difference in the A/C performance when in traffic.
 
Messages
13,092
Location
Indiana
I’m sure they have a reason, but youd likely only see a difference in stop and go traffic in extreme heat.

If most your driving is in moderate temps at highway speeds, I wouldn’t worry about it.

*Heck, it may not even do that.. I’ve seen K-9 unit tahoes idling with I assume running AC with their hoods up. I’m sure there was a reason for that.
 
Messages
36,516
Location
ME
They'd help your ram-air. Something like zipping up a hill in the summer at highway speeds with the AC on.

Stop and go traffic will be handled by your electric fans-- these flaps won't help or hurt that.
 
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