Hi, I have a 2007 G35 sedan with 111k miles.

The coolant leak problem started five to six months ago, where I have been noticing small coolant puddles on the ground after I start the engine in the morning.
I replaced both the upper and lower radiator hoses and several heater hoses but it did not solve the problem.

Today I did a routine oil change and decided to run the engine without the plastic undercover to see if it leaked coolant and identify the leak location.
The coolant is leaking near an area behind the water pump is located. It is a strange area for coolant to leak.

Anyone has any idea why coolant is leaking from this area? And also any recommendations for a fix?

Video of leak location:
https://imgur.com/po0ri2z

Image of where the leak is spreading (from under the car):
https://imgur.com/1L6K5Aj

Image of possible leak origin (used endoscope to reach location):
https://imgur.com/YyU4NKj

 

Definitely not where I would expect to find coolant leaking from. Personally, I would use this as an excuse to tear into the front of the engine and change to oil gallery gasket. I would take another video, but start from above the engine and slowly work your way down to where the leak appears to be coming from. The first part of the video was hard to tell where I was looking. Starting from outside of the car so we can have a good orientation might help somebody identify what exactly it could be.

 

Looks like you need a new water pump. I would clean it really good and make sure that it is coming from behind the timing cover and not elsewhere. We just bought a 08' that the previous owner took to a shop for the same job. Cost him over $500 to have it done.

 

That would be the weep hole in the block for the water pump. You need a water pump.

 

Yes. The leak is from water pump weep hole... I had that problem about 3 years ago. Maybe my G had smaller leak than yours. Not sure?

Guess what? That was caused by that I put 65% water and 35% coolant in its coolant system. So I changed back to use 60% coolant and 40% water. Then the leak stopped completely one month later. I also found that Nissan OEM coolant was more sticky or thick than Prestone. So since that time I always use Nissan OEM coolant... Hope it helps. Good luck! (Now I use 50%-50% and still no leak at all. )

 

Mixture of coolant and water content will make no difference. 100% antifreeze or 100% water is not going to seal a leak or make a leak worse. If there is a leak in you system the only way to fix it is to find the source (IE:hose, pump. radiator) and replace. Duct tape, pour in fix leak crap, ect is just a patch job to get you to a parts store. If you had a leak and it suddenly stopped I would suspect it will leak again soon.