I have been smelling coolant as well. Couldnt see where it was leaking from though. So i ordered a replacement radiator from "genesis auto parts". Package arrived pretty quickly, lifetime warranty, and price was pretty fair ($125). Had the radiator installed on saturday and i am hoping this solves the leaking issue.

 

That was my argument at the Chevy dealer......

Fell on deaf ears.

 

Thanks to those in this forum who have gone before me in investigating the radiator problem.
I didn't know of any problems with my 2007 Hummer H3, purchased one month ago from a GM dealer. It is a one owner with 43800 miles as purchased.

I opened the hood and with a 1/2" box wrench took off the upper (middle) radiator support and: Sure enough, the metal edge had "black plastic scrubbing" where it contacts the radiator and there is an indention in the radiator itself. Not enough to leak yet but it's only a matter of time. There is also a precursor to a 8" or so crack-through on the right side of the plastic top. More like wrinkle lines now but it's easy to see the future of this.
At present I'm going to elongate the bracket hole a bit and place a piece of vacuum tube or similar over the sharp edge of the frame part. I'll then speak to the dealer when I get the first oil change.
It is still under factory bumper to bumper warranty until October 2012 so hopefully that will take care of any problems that arise.

I just joined today and while not looking for problems, the radiator situation stood out and I'm thankful for all the posts on it.
Dave

 

I recently had a radiator leak on my 2007 H3--90k miles. Well out of warranty so no use fighting with anybody.

I ordered a replacement AC Delco radiator (#22000) from autopartstomorrow.com.
$234.00 total cost. Great price, no tax and free overnight shipping. The radiator was an exact match.

Also. I followed the great instructions given a few pages back and the replacement of the radiator was fairly easy,

 

I had a leak on my h3 also and just replaced it today. Too a few hours but the instructions a few pages back were great. If you replace yours, take a pair of pliers and bend the metal on the core support up and back away from the radiator. Then take a file(Walmart for $3) and sand the rough edges smooth. You can then spray paint the metal black again and it looks good as new. Plus you won't have to worry about your radiator cracking from metal contact anymore.

 

I am not surprised some on here have clearance issues with radiator/ core support...however, it seems the rads are just badly made.....mine had an inch of clearance, no signs of rubbing....just the upper plastic tank develops a hairline split ......which is why you smell it but is not obvious leak....is at the very top so you dont see it running out. When mine started leaking, I saw the split. I took it to Tom Gibbs Chevrolet in Palm Coast FL to fix under warranty. What a bunch of IDIOTS! I told them it was the rad on the phone...they said sure , bring it down. I leave it for a couple hrs, dont hear back, so I call em....they say its my water pump not my radiator.. and they say they dont have anyone here capable of doing the repair of a waterpump!!!!!!...I say, wheres the tech who pressure checked it.....they send some lot boy over with a pressure checker pump....I hook it up and say ....why is it spraying out radiator seam, and pump bone dry??? they just looked at me dumbfounded...and sent me on my way with rad. still leaking......I had the deaaler i bought it from tow it back to Deland and do the repair......Tom Gibbs Chevy...what a joke..dont let em touch your car!!!

 

I made a trip to Harbor Freight and bought a cutoff grinder and will be cutting off the lip as someone else did on here. Mine is starting to wear a groove in the support.. not good.

 

Just my 2 cents, but that lip is there for a reason....cross vehicle structural rigidity. Think of an 'I' beam or an 'L' bracket. Now think of them without the perpendicular leg....a flat piece of metal. There goes your strength!

 

tom....you missed your calling....you shoulda been an automotive engineer. Just think of ALL the money the auto companies coulda saved on 'short-cuts', 'skimps', 'work-rounds', and unnecessary time spent on design, engineering and testing. They wouldn't have needed the bailouts!

 

What!?! Doc's not an engineer? You mean I've been taking advice from the wrong guy all along? Oh snap...