08 Vert, 14k miles. Just noticed about 1/8 cup of coolant under the car. It's probably dead center left to right between the wheels under the engine. I took a pic and tried to draw a circle around the bolt where I can see some coolant. It almost looks like it may be coming from above the bolt, but I can't be sure. The pulley was pretty wet below it though. Any ideas on where to start looking? I'm no mechanic and will most likely be taking it in, but I wanted to get an idea of what I could be expecting. Thanks.

 

more than likely it's coming from the water pump

 

Unless coolant is running down the underside of the upper radiator hose, your water pump is leaking. A new OE pump is $275, plus coolant, plus labor to install. It's a pretty quick job.

 

Thank you both. Looks like a new water pump is in my immediate future

 

One quick question. Do I need to go with a brand new GM part or is an off brand remanufactured ok? A mechanic I used in the past said it'll be around $325 going with remanufactured. Thanks.

 

Install is not that hard and im no mechanic..bolts on and off..about 2 hours..and 12 dollars for new gaskets..

 

Mine did the same thing at 30K in 2010. My leak was so small, I had to put a pressure test on for 24 hours to actually see the leak. It was coming from the water pump seal.
I suspected I had a leak when I could smell glycol occasionally, and then a few drips on the garage floor.
I replaced it myself in about 4 hours. I took advantage of a drained system to change out all my hoses to silicone hoses.

I bought a new GM OEM pump in 2010 for just over $200.00. GM Parts Direct ($212.50) and
Cultrag Performance is ($275.85)

 

The GM waterpumps are not well designed and not very durable.
But so far, no one has mentioned anything that's really better.

I'd like to hear differently...

 

Ok, new twist on this. Took it to the mechanic expecting to replace the water pump. He called me a couple hours later after pressure testing it. No leaks were found. In fact he couldn't find a leak anywhere. Drove it home and put a pan under it. 48 hours later, no drips. 5 more days pass without driving it and when I pull out of the garage, I noticed about 2 tablespoons of coolant. So, it leaked between 2 days and 7 days after being parked. Any ideas on this?

 

I've previously answered to this thread. The mechanic did a pressure test for what??? 20 minutes, maybe an hour tops???
My past story parallels your almost to a tee.
I could smell glycol occasionally when I parked, could find no leak.
Checked every fitting, etc etc. At times, there would be a few drops on the garage floor.

I bought a Pressure tester, and did a pressure test (much like your mechanic did) and found nothing.
In the next month or so, only very occasionally would I smell glycol, and still no sign of a leak, maybe a drip on the floor.

I was determined to find that leak...I knew there was one somewhere.
I put the pressure tester on at 18 psi, left it for 24 hours, and in that time the pressure dropped only 7 psi.
I looked to find the leak, or drip or anything, and I finally saw a small stream (drip) of antifreeze (glycol) from behind the water pump pulley, and even saw small amount of a liquid or wet shine on the pulley belts, just below the pump, where the leak had dripped on the belt.

I then knew that the pump seal was leaking, although very little, and probably only when the shaft seal was stopped in the right position. I was thrilled to finally find the issue!!!!!

Here is the pic of the old pump.




I have put 40 K miles on the replacement water pump, and not a sign of any more leaks anywhere

I'm betting that 99% it's your water pump seal leaking.
Eventually, if you don't change it, it will leak more and more, get glycol all over the place, soak your belts, coat your hood insulating blanket etc.

If you've checked every fitting, hose clamp and have not found a drip, leak etc, then what else can it be???
GM water pumps are known for seal failures. I've replaced a water pump on almost every GM vehicle I have owned, with enough mileage put on it.
Leaks are hard to find because most times they fall on a hot engine block before they have a chance to puddle.
Only when they get leaking badly, are they easily spotted.
With the vette, it happened at just below 30K miles.

 

08 vettes have a LS2 water pump,which cost $397.42.The 09 & up have the LS3 pumps.I don't know if a LS3 will work or not,they are less $292.42.Good luck.

 

The pump on my Z leaked the same way. It would sit for a day or so and then drip a little. One day I had my car up on the lift doing something under it. I took a lunch break and there was nothing on the floor. When I cam back a half hour later there were two drips on the floor. The pulley was wet, the back of the water pump was wet. Dealer replaced the pump and problem went away. If it isn't leaking when you check it feel behind the pump and see if it feels sticky. Dried coolant will feel sticky.


Bill

 

Reviving the thread to add relevant info since this is one of the first threads which google shows when searching, and OP could have potentially been dealing with the same issue.

I had a very slow coolant leak from the exact same location for which would every few month or so cause the DIC to give me a check coolant level warning, as well as coolant covering the lower front of the engine and front subframe, but not the radiator area. Coolant temps were not really affected significantly yet by that point.

The leak was directly over those pulleys and would also cause a belt squeal the first time I accelerated while turning after a cold start.

I found the cause of mine as a weak hose clamp/improperly placed hose over the water pump output nipple. The hose was sitting in the same location on the nipple as the hose in OP's picture. Barely touching the clamp while hot resulted in a fine mist of coolant spraying out of the fitting.

After moving the hose over so it was flush with the water pump, the fine dripple of coolant stopped, as well as the 5 seconds of belt squeal that would occur after the first time I put a load on the belt with the PS pump at ~2-3k rpm. Touching the clamp while coolant is pressurized no longer has coolant spraying out as the barb on the hose is securing it properly.

Apparantly that first section of the water pump fitting is not an indicator of where to place the hose, but just a barb which the hose goes over in order to secure the hose on the fitting.