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Discussion Starter #1
2001 D-max with a fuel leak problem. Looking for some info. Leak is coming from in front of the fuel tank. Not sure if its a fuel line or the other "thing" thats mounted there. Q-1: What is this "thing"? and Q-2: WHat is its function?
Thanks in advance for any help!
 

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if it looks like a miniature radiator its your return line fuel cooler, cools the fuel down before it gets to the tank so pressure doesn't build up...mines leaked before
 

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Discussion Starter #3
usaf- thanks for the info. Is it a b%^&* to changeout? The fuels lines on mine look pretty corroded around the fittings. Looks like I may have to replace one (or more)of the lines. Thanks again!
 

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Probally the connects for the return lines, they can corrode and leak. Start the truck and let it idle while you look at the lines. Is it taking longer to start?
 

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Discussion Starter #5 (Edited)
Its not taking longer to start. It seems to start in about the time it always has. I started it while looking at lines etc, and I cannot see exactly where its coming from. I plan on wiping all down and taking another look today. How ofter does the fuel cooler/press relief "thing" go bad? Is this common? Just wondering. Thanks again for the help.
 

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There is no pressure in the fuel lines or the return lines. The return just comes from the engine, through the cooler and dumps into the fuel tank. The fuel supply lines run on negative pressure, as the CP3 pulls the fuel from the tank.
 

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guess i was wrong about them having pressure lol learn something everyday right :)
 

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The fuel return line has pressure just not much, the feed line can leak, just not while the truck is running that is why I asked if it is starting more slowly, from air intrusion from a leak on the feedside.

To the OP, yes there have been some issues with the connections to the fuel cooler and corrosion/rust.
 

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mine kept blowing the connection from the airdog to the stock line. I finally just cut the spring clip connection out and clamped the hose (2 clamps) back to the steel line. Has not leaked again.
 
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