Upper/Lower Air Deflectors (Help cool your car)[*]

**drunknmunky** · 04-23-2008

This writeup on Upper and Lower Air Deflectors has been added to the How To section and can be found HERE.

**Zef_66** · 04-23-2008

I just checked PACE Performance - GM Parts, Crate Engines, and Aftermarket Accessories They have everything for $43 shipped. And they usually have things in stock. But can't hurt to call and find out. Also, if type clubgp in the Where did you hear about us box, you might get a small discount.

Just for comparison.

**drunknmunky** · 04-23-2008

awsome, i always forget about pace!!! thanks man!!! another good addition for anyone looking. the only good thing about the dealership is they cost a little more, but (for my dealership atleast) if i order by lunch, i get it the next day!

**Sabrewings** · 04-23-2008

These pieces are pretty important pieces to the cooling of your car. The lower piece creates an area of high pressure in front of the radiator and slightly lower pressure behind it. The upper piece keeps the high pressure from escaping over the radiator and instead it goes through it. Thus, you get more air through the radiator than if they weren't there.

The radiator doesn't see much air otherwise due to the front design on these cars.

**drunknmunky** · 04-24-2008

exactly the reason this was created. you'd be surprised how many people are missing one or both!!!

**trishieldfan** · 04-27-2008

My buick didnt have the upper one and from what i see they dont come with them. I had broken the lower air deflector and had taken it off. I had made a radiator plate out of stainless and made a lower pan to smooth the air out from the radiator to the frame. That had made a 15 degree drop at least. This was on a 95 degree day. As of lately it has actually dropped more adn the car runs much better. Its amazing how such a small thing can make a huge difference.

**Going Too Phast** · 05-25-2008

Nice writeup and good pics.

My '98 was missing that upper baffle when I bought it. Those of us with '97-'98 GPs can utilize some of the cooling improvements that were added to '99s.

Instead of that upper baffle, the newer GPs got ducts that go directly behind the grilles and direct air into the radiator. The part numbers are 10423209 (Right) and 10423210 (Left). I added them to my '98 and they fit perfect. Those ducts and the upper baffle are mutually exclusive however.

The lower baffle was redesigned in '00 according to the parts list. The new lower baffle part number is 10423208. I haven't tried using it and I believe it is not a simple bolt on as it requires a little work to attach properly. I plan on getting one installed at some point though.

The most important upgrade is the newer fans that were added in '99. They are shrouded and are supposedly ~30% more efficient than the older fans. I got mine from Ed Morad for a really good price. They will bolt right in although I had to do a lot of wrestling with large wiring harnesses before it would fall into place. Make sure you remove the plastic tranny cooler line holder from the bottom of the radiator support before putting the new fans into place.
Comparison pic of the two different fan styles:

**matt5112** · 08-16-2009

Funny thing about mine... the upper ones didn't line up in an efficient manor.

Also, it doesn't seem to be reaching the entire rad, just covering spots here and there.

Another funny one i noticed is the stock air box draws air from behind the drivers headlight... because thats the "coolest" spot they could find.

**matt5112** · 09-15-2009

Question: Is the lower baffle supposed to be on an angle or perpendicular to the ground?

**Bio248** · 09-15-2009

it ends up being at an angle towards the back of the car.

**matt5112** · 09-15-2009

Originally Posted by Bio248

it ends up being at an angle towards the back of the car.

Mines perpendicular to the ground, hence asking.

**Skeeve** · 09-30-2009

After my rad clogged i did a super flush... refiled with coolant, ran it for another 1000 miles, did another flush, the coolant looked like baked dex(went in yellow), decided to leave off the bottom one for easier access as i was planning on doing it again soon just to get all the dex buildup out, car started overheating bigtime after that and i didnt think anything about the lower piece at all, finally put it back in yesterday VIOLA! no more overheating while driving, then ran across this today.... LOL
But yes, these pieces are very important to keeping the car cool... excellent write up!

**Silent Drifter** · 10-24-2009

I looked on my car, and I do have the lower, but don't have the upper air deflector. I might have to check my dealer, and see how much it costs. I'll probably buy one anyways, when my next check comes in.