Bumper air dams

[Bob_Barrett]

Just wondering if some of you have an opinion as to whether an air dam serves a purpose, especially when towing . I have an older 95 Silverado that seems to have alot of heat that builds up in the engine compartment. The gauge reads normal , and i have added a tranny cooler, but not an engine oil cooler . From what i can read the air dams channel some of the air into the radiators and condensors for AC . Most of my camping destinations are within 60 miles , once a year a beach trip that is 140 . As i build up a little more experience we plan to venture a little farther

Bobby Barrett
05 Zepplin 28 ft tag

[steve-n-vicki]

sch911 wrote:
The air dam is to assist in low speed stop and go traffic cooling. It's there to stop hot air from the engine box from recirculating back into the condenser and radiator. They have no affect on helping cooling while driving down the road.

Not a tow truck but if you knocked the air dam off of a dirt late model you would soon be in the pits with an overheated engine, they do work at speed to direct air thru the radiator

[bartlettj]

I recommend changing the transmission oil to synthetic. I've been running Dexron VI in my 2003 Tahoe for several years and it has made a difference in shift feel as well as oil temperature. It also holds up better to sustained hot temperatures. I changed mine by flushing the old fluid out the cooler send line into a bucket with the engine running at idle. Since that is after the torque converter but before the valve body, it means that most of the old oil doesn't mix with the new.

[hawkeye-08]

JIMNLIN wrote:
Our older trucks didn't have a air dam. The result was heat would pack up in the engine compartment.
The lower air dam creates a low pressure area under the engine bay which allows a better air flow through the radiator to flow through the bay and on out the bottom.
I found out the hard way on a 3500 DRW chevy when the dam was broken off hauling cattle out of a pasture. The result was a hotter running 454 at interstate speeds.

X2

[Bob_Barrett]

Ok , Just to let you know that i did buy a new air dam , and yes it did have one on it from the factory . The man i bought the truck from had let his girlfriend borrow it , and of course she wrecked it , totaling out mostly the bumper & windshield, thus no air dam on the truck
Last fall trip in late Sept , so will get a test drive then .Thank you all so much for the replies and input . This site really great for us rookies

[bucky]

The term valance, air dam, and baffle are being used interchangeably so what follows pertains to all 3.
First a reply to sch911. Why do all your (FCA) trucks have them if they serve no purpose?
Bob, your 95 most certainly had a lower deflector on the front bumper from the factory. If it's a 4x4 it had cutouts for the tow hooks. It most certainly has an effect on both cooling and aero. Aero=mpg. I think most people that know what they are talking about will agree that the lower you are the more cleaner you are from an aero standpoint. This means your RV as well and it's why towing nose high will impact your mileage.
Some vehicles also have a baffle right at the bottom of the radiator core support to further help in cooling but they are more common on passenger cars that are already low enough bumper wise.
If it was my truck I would put one back on. Even Amazon sells them, along with several other AM companies. The GM ones are a little pricey in comparison.

[Huntindog]

BB_TX wrote:
Interestingly, this article from GM does not mention any thing about cooling related to air dams, only aerodynamics.

Yes, but that only applies to the truck that was in that test. They did mention cooling as part of the entire package in ducting that prevents air from swirling in the body behind the grill. (thus forcing it thru the radiator).. A 2014 GMC.... The focus of that article was areo dynamics, not cooling even though the two are related. No matter. The OP doesn't have that truck. He has a 95 Silverado. That is a very different application

[LarryJM]

Huntindog wrote:
Over on the Automotive air conditioning forums, they sure think that the air dams are important for increasing air flow thru the condenser.... (And since the radiator is right behind it, then it has to increase airflow thru it as well.)

WOW I guess my "GUESS" was good since I didn't research it or repeat what I had heard/read somewhere previously.

Larry

[Huntindog]

Over on the Automotive air conditioning forums, they sure think that the air dams are important for increasing air flow thru the condenser.... (And since the radiator is right behind it, then it has to increase airflow thru it as well.)

[LarryJM]

Muddydogs wrote:

Bob Barrett wrote:
Just wondering if some of you have an opinion as to whether an air dam serves a purpose, especially when towing . I have an older 95 Silverado that seems to have alot of heat that builds up in the engine compartment. The gauge reads normal , and i have added a tranny cooler, but not an engine oil cooler . From what i can read the air dams channel some of the air into the radiators and condensors for AC . Most of my camping destinations are within 60 miles , once a year a beach trip that is 140 . As i build up a little more experience we plan to venture a little farther

Bobby Barrett
05 Zepplin 28 ft tag

So your temp gauge reads normal but there seems to be a lot of heat build up in the engine compartment? You do realize that your engine is running around 200 degrees, made of aluminum and metal as well as being surrounded by metal right? Your engine compartment is going to be hot once all that metal warms up.

The air dam has little to nothing to do with cooling as it's designed with the rig's aerodynamics in mind. Air dam's are designed to reduce the drag under the vehicle by forcing air down to the ground reducing air drag under the truck. So actually an air dam might cause the engine compartment to be even hotter as its forcing air away from the underside of the compartment.

My guess and it's only that is while most of what you say I agree with the air dam might help to reduce "leakage "(for lack of a better word) air not being "forced" to flow thru the radiator so it basically helps make the air flow thru the radiator more efficient. This is sort of creating a baffle of sorts directly behind the radiator.

Larry

[Muddydogs]

JIMNLIN wrote:
No use being snarkey ...... I sure don't know more than GM engineers but I do know they help improve air flow through the engine compartment at highway speeds and do little in low speed driving such as in city type traffic. We are talking about working trucks and towing duties.

Radiator fans were once controlled by engine rpm now most are done electronically.
Low speeds/low engine rpms/city traffic the fans work as engine temps rise such as sitting in traffic or pulling a trailer up a steep grade.

Get out on the highway at high speeds and the fans shut down as the air flow increases.

A google has lots on the subject of the lower air dams on our trucks and what they do.

The fan shuts off at high speeds due to the ram air coming through the grill and radiator cooling the coolant off, at low speeds there is no ram air so the fan turns on to pull air across the radiator fins to cool the coolant. The fan will also come on at high speeds if required due to high coolant temperatures to pull more air across the radiator fins to help cool things down.

The air dam doesn't help with air flow through the engine compartment as air is already flowing through the grill, radiator fins and out the bottom of the engine compartment. The air has nowhere else to go but out the bottom of the engine compartment as the hood, firewall and side body panels restrict air flow.

[JIMNLIN]

No use being snarkey ...... I sure don't know more than GM engineers but I do know they help improve air flow through the engine compartment at highway speeds and do little in low speed driving such as in city type traffic. We are talking about working trucks and towing duties.

Radiator fans were once controlled by engine rpm now most are done electronically.
Low speeds/low engine rpms/city traffic the fans work as engine temps rise such as sitting in traffic or pulling a trailer up a steep grade.

Get out on the highway at high speeds and the fans shut down as the air flow increases.

A google has lots on the subject of the lower air dams on our trucks and what they do.

[sch911]

JIMNLIN wrote:

sch911 wrote:
The air dam is to assist in low speed stop and go traffic cooling. It's there to stop hot air from the engine box from recirculating back into the condenser and radiator. They have no affect on helping cooling while driving down the road.

Actually the air dam does little at low speeds around town/city traffic.....thats where the trucks cooling fan(s) come to play.
The lower air dam creates low pressure under the engine bay at speed allowing better air flow through the engine bay and on out the bottom.

Some years back one GM truck forum had pics and diagrams of air flow through the radiator and out the bottom of the engine bay with a without the air dam on trucks at various speeds.

Well apparently you know more than the OEM engineers who release them I guess.... Sorry but that's why it's there!

[BB_TX]

Interestingly, this article from GM does not mention any thing about cooling related to air dams, only aerodynamics.

[JIMNLIN]

sch911 wrote:
The air dam is to assist in low speed stop and go traffic cooling. It's there to stop hot air from the engine box from recirculating back into the condenser and radiator. They have no affect on helping cooling while driving down the road.

Actually the air dam does little at low speeds around town/city traffic.....thats where the trucks cooling fan(s) come to play.
The lower air dam creates low pressure under the engine bay at speed allowing better air flow through the engine bay and on out the bottom.

Some years back one GM truck forum had pics and diagrams of air flow through the radiator and out the bottom of the engine bay with a without the air dam on trucks at various speeds.