Coolant leak from cat converter area

A forum for the legendary Nissan Pathfinder and Infiniti QX4.
9899pathfinder
Posts: 53
Joined: Mon Dec 26, 2011 8:56 pm

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'03 QX4. Have a slow drip of coolant. It is dripping off the cat converter. The truck runs fine & there is no white smoke from the tailpipe. Mostly at this point it is just a bit messy and requires periodic refilling of the coolant tank. From some research, others experiencing such leaking believe that the source could be somewhere above the cat vs, the ca t itself. Anyone experienced this on a QX4 or Pathfinder of this vintage?


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VStar650CL
Technical Expert
Posts: 11927
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

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The best way to locate mystery leaks of oil or coolant is a spoonful of UV dye. For coolant, the most effective course is to add the dye cold, top up the coolant, warm the vehicle, then look for dye after shutting it off. The coolant will "cook" in the hot block for 10~15 minutes after shutdown because it's no longer circulating, so that's also the point at which you'll see maximum cooling system pressure. Because the engine and vehicle are stopped, there also won't be any issues with airflow blowing the dye around. If you do find what looks like a spray pattern, it means a vapor or pinhole leak that's condensing and running down on your cat.

9899pathfinder
Posts: 53
Joined: Mon Dec 26, 2011 8:56 pm

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Just what I was seeking. Going to give it a try. Thanks.


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