JF Ranch

One year ago, I bought my first Corvette. A 1999 Convertible, auto transmission, 54,000 miles, bright red with white top. Both my wife & I love this car.

I've been concerned about high coolant temps a few times when we were in fairly harsh driving conditions (I could explain this further if necessary). I had the cooling system flushed and checked by a large Chevy Dealership and they told me the system is working properly. No codes and the fans are working properly: low at 219 degrees, high at 228. No work was recommended or done.

This car was missing the center section of the 3-piece front air dam when I bought it. The previous owner probably scraped it off of too many curb stops. I've been meaning to get this replaced but have not done it yet.

I have been told that the air dam is vitally important to the cooling system.

Can someone explain if this is true and why?

Thanks, John

4XLR8N

Yep, it is...it directs air flow through the radiator. I would highly recommend installing a new one asap.

tpr60

Sac. City Corvettes has a fan kit for c5's that lets you manually control the fans while also leaving the computer do it automatically. Have them on two Vettes and they work great. Replace that missing deflector.

knewblewkorvette

You NEED it, only about $100

JF Ranch

Thanks for the comments! I've been procrastinating, but will get one ordered ASAP. Is there a preferred vendor? Or should I go through a GM dealer?

Even though I have not carefully examined the underside of the radiator/air dam area, I don't understand how this can make so much difference. My first impression is that it would deflect air flow down & away from the engine area. Or does it direct the air flow up into the radiator instead?

coia96vette

It is needed. It directs the air into the radiator after 35mph. That is when the fans automatically shut off and cooling relies on the air flow coming up from that air dam.

rrwirsi

[QUOTE=JF Ranch;1595405397]Thanks for the comments! I've been procrastinating, but will get one ordered ASAP. Is there a preferred vendor? Or should I go through a GM dealer?

Check the forum vendors. Check ZIP. http://www.zip-corvette.com

Part Number ET-411

Velocity_Vette

You need it because the air dam in resting position pushes air upwards along the shroud both the radiator and condenser rest on. Without it, too much air is evacuated underneath the car and completely misses the upwards travel.

There is absolutely no reason to remove it and why a prior owner would have done so is concerning (more concerning would be if all the hardware is intact, which if the air dam was removed it all may have been discarded). I'm lowered and while I still see some scrapping the air dam is spring loaded, so anytime it's pushed against it flaps back into place once over the obstruction. At the absolute least, some owners have trimmed say an inch or so off of it, but ultimately it needs to be there.

JF Ranch

Thank you everyone. I have found several options for replacing the air dam. I will get one ordered ASAP! You all have been very helpful.

romandian

i have bolted i strip of durable rubber down there. it sits pretty low, about 2" above ground and scrapes now and then but is indestructable. keeps engine really cool.

striper

I have two additional suggestions while you are under the car replacing your air dam. First, you consider blowing clean the radiator and a/c condenser core. They fill up with a large amount of dirt because of them being bottom feeders, enough to affect your coolant temps. Wear eye protection, much dirt will blow out. Secondly, you consider improvising a screen to span the opening that spans radiator opening. This will prevent larger objects from getting sucked up there and blocking off the area. They can and they will.

JF Ranch

Thanks again everyone!

However, one more question while still on this topic. As I mentioned in my original post, I had a GM Dealer check the cooling system and they told me the system is working properly. No codes and the fans are working properly: low at 219 degrees, high at 228. No work was recommended or done.

It is obvious from everyone here, that the air dam plays an important role in engine temp cooling... Why would this large Dealership NOT say anything about the missing air dam and offer to replace it?

jjc508520

Part of the equation is if you are running a different thermostat and if a tuner has "tweaked" your fan settings. I run a 165deg thermo and I've had a tune - I'm going to trim the dam down (but keep it in place) to try and reduce scraping...

rrwirsi

If the dealer cannot see or mention about an obvious missing part for cooling, what else do they not know about the C5. Stay, no, run away from this stealership.

JF Ranch

Yeah, that's sorta what I was thinking.

Vetteman Jack

No clue why the dealership didn't say something about the missing air dam- after all it is an integral part of the cooling on the car.

JF Ranch

Wow! a comment by the MODERATOR!!

At the time that I had the dealership check the cooling system, I did not realize the important function of the air dam. Since I am not the mechanic that most of the members are on this forum, I must place trust in those who do my work. It is disappointing, to say the least, that a large GM Dealership would not see this problem and inform me about it.

Typically a service shop will find things to fix, necessary or not, to enhance their bottom line. It is surprising that they did not see this as an opportunity to earn more money, while performing a valuable service.

Thanks to all here who know their stuff!! This Forum is a valuable resource.

CactusCat

Haha...not being mean but its obvious you're new here. That's ok! Your post was "Wow, a comment by the Moderator!!" Before VetteMan Jack became one of the moderators, I think his post numbers were somewhere around 250,000 posts!! So you see, we don't think it's unusual for VetteMan to post at all. He's a great guy from the state of Missouri. You'll learn that he's a very smart and friendly person.

JF Ranch

Yep. I'm new here. I became a Corvette owner just one year ago. I enjoy the articles in the newsletter and the camaraderie among Corvette lovers! Again, this Forum is a great resource. Thanks for all the interesting comments to my question!

lionelhutz

I've seen a number of people post that they run no air dam and it didn't have any noticeable effect on the cooling. So, I wouldn't put a great deal of faith in it fixing your woes.

I do as already suggested and make sure the radiator and condenser are clean. The dealership might not checked the coolant and fans, but they might not have put it on a hoist and made sure the radiator fins were clean. They will look clean from the engine compartment fan side.

Also, what does harsh driving conditions means and what did you consider high coolant temperatures?