I have a 1995 Maxima with 143,000 miles. I am losing coolant and at a loss to find the leak. I lose 10 ounces of coolant ever 250 miles. Have checked the water pump, hoses, radiator cap. heater core etc. I can find no evidence of a leak. The oil is clean and I get no smoke or sweet smell out the tail pipe. The only unusual thing is some apparent staining on the exhaust manifold ( no sure how long it has been there)

Could I have an internal leak that does not affect the oil--by the way car runs great no problems no codes. I have read that Maxima has cooling lines running to the throttle body--could that cause the loss and not affect performance.

Thanks for any ideas.

 

You don't have a very big leak - yet. It is possible for the coolant to be evaporating before it drips, especially if it is hitting the exhaust. Usually dried antifreeze looks like you drove through a mud puddle.

Go to an auto parts store and rent a cooling system pressure tester. If the engine is cold and you pressurize the cooling system, maybe you will find the leak. Otherwise you will have to live with it until it gets worse.

 

I was losing water and couldn't find the leak, until I crawled underneath and saw staining on the under side of the heater hoses where they went into the T on the firewall. I replaced both hoses and that fixed it.

 

checked heater hoses

 

I'm trying to figure the same thing out on my fathers 07. No visible leaks. :/