Here is the cheapest rad I could find with a Limited Lifetime Warranty.
Discount Auto Radiators - 2006 Hummer H3 Base 5 Cyl 3.5L

About $120 shipped.

 

Same thing happened to me a couple of weeks ago. Smelled coolant, took the 2007 H# to my local GM dealer and the radiator had a leak. The vehicle only has 41k on it and the bill was going to be approximately $700 since it was out of warranty. Kudos to GM however, they repaired my Hummer at no charge. For those of you that may not know, GM is working hard to increase their customer satisfaction rankings. They have been repairing vehicles under a "Good Will" policy. If you have the same thing happen to you, ask your local GM dealer's Service Manager if they will send a request to GM to repair under "Good Will". Hope this helps.

 

Well I have to add my sad story to this forum tonight. My 2007 H3 now has the exact same crack on the top of my radiator and it too is on the driver side. But I bought a repair kit that you clean, sand down, and apply this rupper coating. I called the dealorship and quoted me $1093 for a new radiator and labor. (Seattle Wa) I will call the 1-866-486-6376 to see if I can get a complaint number. I will also call my dealership again tomorrow and ask for them to cover the cost under "Good Will." I will post my findings tomorrow.

 

On the positive side, the radiator is a piece of cake to replace and the OEM AC Delco part is available on line from many sources for less than $200.

It's also one of those repairs that I'd feel comfortable farming out to any decent shop to avoid high dealer pricing.

 

So I called and got it filed with Hummer. I have a file number that I will be bringing tomorrow to my local dealership. I hope to get this replaced for the $100 repair and not the $1093 I was quoted. I'll post tomorrow with my results.

If you own a 2007 H3, just call and report your cracked radiator. The number is 1-866-486-6376. The more calls they get the better chance of this becoming a recall and nobody else will have any issues with this problem.

From one H3 owner to another.....

 

SUPER GREAT NEWS!!!!!!

Thanks to this AWESOME Forum, I am now getting a new radiator paid for by Hummer! Calling Hummer directly and getting it filed worked. And the Super Great service at the Bellevue Cadilac Hummer Saab Dealership in Bellevue, WA made it all happed flawlessly. Justin made the call back to Hummer and said he's seen this before and they took care of everything. I couldn't be more happy!!!!

 

Congrats. Glad I could help

 

Just wanted to be one of the many to report that my wifes 2007 H3 started leaking coolant this past weekend. looking under the hood revealed what everyone has posted, there is a groove cut into the radiator behind the hood latch from contact between vehicle body and radiator and a crack along the top of the radiator just right of the contact point. Our hummer has 56K miles, never been off road and is still in mint condition but GM or hummer states that they have no fix for the radiator rubbing against the metal lip behid the hood latch. The rep. that I have been speaking with as of today stated that she was not aware that anyone was having problems with this issue. I know 2 other h3 owners in Dalton, GA and I notified them and both reported that they had checked and also have a groove being cut into the center of their radiator also. GM refuses to own up to their design flaw, You would think that since our tax money was used to bail them out and keep their doors open they would be more willing to right their mistakes!!!! As of today 4/27/12 still waiting to hear from hummer on whether GM will help and assist with the cost for the repair.

 

I didn't find out about this forum till I was searching how to fix a front turn signal bulb.Low and behold last month I shelled out $1000.00 for a cracked radiator in my 2006 H3 with 110,000 miles on it.Not at a dealership Any recource on that ? I think I already know the answer.

 

the fix was posted last year,you can cut abt 1/4 inch off the metal and free up the rad so it floats free. there were pix.