new to forum: what will happen if....?

[ratboy]

Hey folks, new to this forum. Found it by looking for a specific problem on the web. I see where some of you had this same problem: I noticed a fuel leak under my '06 crewcab 3500 DMAX just in front of the fuel tank. Investigation revealed what appear to be, at first glance, a small heat exchanger/radiator on the return line. After scratching my head a while, wondering what ever could this be (I'm relatively new to diesel technology), I decided to call my Dad. He is an old school self taught diesel mechanic (owner-operator 18 wheeler) and is always my first call when working on anything mechanical. He of course, was not familiar with this particular application of a cooler on a return line and thought it might have something to do with helping to heat the fuel for winter-time. However, as I pointed out to him, this cooler was on the return line and had no additional lines for adding heat. So, being stumped, and needing to get to work by monday morning, I removed the cooler, cut the leaking fittings off and hose-barbed the to lines together.

Here's my question(s): What negative effects will this have on my DMAX? How much good does that thing really do, buried inside the frame rails with little air movement? SHould I look to re-install with better (stainless) fittings? And if so, where would I find them? Thanks in advance.

[THEFERMANATOR]

It is the fuel cooler, and I would not reccomend running without it. Chances are all that was leaking was the o-rings inside of the quick connects. Common rail diesels run at VERY high fuel pressure, and bypass alot of this heated fuel to the tank to be cooled by that cooler. Hot diesel is a killer of common rail injectors and CP3 pumps, and is why GM put it there. It removes alot more heat than you might think under there and gets more airflow than you would think. Check as your cooler may have 1/4" pipe fittings in it like my 01 cooler did so you may be able to put hose barb fittings on it and hook it back up.

[JohnC]

Was it the cooler leaking or the "quick connect" fittings? On mine, the fittings when bad. I redid it with hose clamps and all is well.

Here's my story...

The cooler is necessary.

[moss6]

Don't know if it's needed or not. The 2011 LML's don't have one, don't think the 2012's do either, but the bracket is still there; I used it for mounting an on board compressor.
Randy

[THEFERMANATOR]

Don't know if it's needed or not. The 2011 LML's don't have one, don't think the 2012's do either, but the bracket is still there; I used it for mounting an on board compressor.
Randy

2011+ use a completely different CP4.2 pump that makes more pressure MUCH more efficiently as well as using PIEZO injectors instead of the old style solonoid type. I believe the 88 DMAX swap truck doesn't have one, but I wouldn't run without one if you could help it.