Leaking coolant...advice needed
 

2005 C6 w/ 10k miles.
The car is dripping coolant overnight directly under the passenger side of the radiator. I have jacked the car up and inspected thoroughly. It's hard to pin point where the leak is but my gut tells me it's where the plastic portion of the radiator mates with the aluminum center. Do you guys have a sure fire way to diagnose the leak without assuming it's the radiator and throwing money? I cleaned everything well and inspected again this morning. It's a small leak. :cheers:

Check while its running.

Its either the overflow tank,the radiator or the hoses. You should be able to see which it is with the engine running.

Sounds like a leak in the bottom of radiator. Have system pressure tested.

10 4
Thanks

I had the same thing happen on my 05 this winter. Overnight dripping from right beneath the radiator on passenger side. Could not find the exact point of the leak but knew it had to be the rad. Once I pulled the rad out i could see that the passenger side radiator end cap was cracked. Apparently not an uncommon issue with todays radiators that have a metal core with plastic end caps.

I bought a DeWitt's. 100 metal. A work of art actually. Direct, no hassle, drop in replacement. Way, way better quality, imo, than the GM rad. Lifetime warranty. As a bonus my running temps dropped due to the Dewitt's.

Good luck with the repair. It's not hard, basic hand tools.

B

I'd check auto zone and see if you can rent a cooling system pressure tester. That's the best way IMO.

The plastic on the radiator has cracked due to age and non use.

Tom

Most likely water pump is giving up. Leak is usually from the weep hole.

I had a small leak recently on my 06 50k. Ended up being the water pump. I would fill the coolant tank then the next morning there would be a puddle under the car. Do you see coolant left around your motor from it? I purchased the Ac Delco part from amazon also came with the thermostat attached. Around $200 shipped and installed myself it is fairly easy and hasn't leaked a drop since.

Thanks all for chiming in...this sounds like exactly what's going on with my car. Thanks.

Just an update. It was the radiator. Had a small crack in the plastic tank on the passenger side. I installed a new OEM unit and she's good as new! Cools perfect with no leaks.

Some years ago, my son's Acura Integra developed a leak (it actually happened right after we had the timing belt changed in New Orleans at an Acura dealer so I think they punched a hole in it, but no proof). They wanted about $800 to replace the radiator. Instead, we brought it home and took it to a local radiator shop. I'm fairly sure they actually make the radiators in their shop, but anyway they're all copper core, no plastic anywhere. I got it put in for about $180, and it was much better quality than the OEM. I don't understand why carmakers insist on using inferior parts.