Keith Browning Posted August 18, 2006 Share Posted August 18, 2006 It's a 2004 F550 dump truck and the owner loads it heavy and has a lead foot. Regardless, the CAC tubes should not keep blowing off at the turbo. We inherited this truck from another dealer and the history on this concern goes back almost 15,000 miles. IT has had the duct, tubes, clamps, MAP sensor and turbo replaced. My diagnostic data shows that there is no over boost condition and the duct is properly installed/aligned. I called the Hot Line and I asked about the possibility of the after cooler being restricted (they said good thought) and they threw in soft engine mounts causing the torque to pull the duct off. First, the engine torques toward the duct during acceleration killing that idea. I removed the CAC ducts and inspected them, for anything stuck in them I know but ya gotta check. I pulled out the ol' borescope and inspected the after cooler which was very clean and there was no oil collecting in it. Then I decided to drill a hole and install a test fitting on the hot CAAC tube, cleaned it out and put the trick together. I monitored boost at the duct before the after cooler and at the MAF hose. I show 30 PSI at the duct and 24 at the manifold and the MAF reading matches with 24 PSI. So I measure a difference, or a restriction of 6 PSI through the after cooler. The HotLine thinks that's too much. Regardless, I don't think that a CAC tube should blow off at 30 PSI or even 40 or 50! Opinions? Ideas? Comments? /forums/images/%%GRAEMLIN_URL%%/smirk.gif Quote Link to comment Share on other sites More sharing options...
pcassidy111 Posted August 18, 2006 Share Posted August 18, 2006 Through my limited experience on the 6.0L (I work at an independant) I have found it necessary to retorque the hot CAC tube hose clamps up to 6 times over a 2 day period before they will maintain 100-106 in/pounds, especially when using new clamps. I have found that after torquing the clamps to 106 in/lb and going through 1 engine warm up cycle the clamps 'relaxed' to 74 in/lb. I know it is probably not 'real world' to be able to retorque the clamps over a 2 day period for you. All of the trucks that I have done this on belong to the steel yard and tow yard down the street so I just tell the dispatchers that to have the drivers stop by on their way to their jobs. No oil leaks or tubes blowing off so far. Quote Link to comment Share on other sites More sharing options...
dieseltech Posted August 18, 2006 Share Posted August 18, 2006 I had a F-550 sevice truck doing the same thing after several visits I found the turbo was over boosting. It never set a over boost code. Quote Link to comment Share on other sites More sharing options...
jaysonfordtech Posted August 19, 2006 Share Posted August 19, 2006 I have seen this before also. I found some have a map that is not correct, but most are just turbos that stick hot only. I have had some I had to drive for 15 or so miles at 70 on the interstate. Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 19, 2006 Share Posted August 19, 2006 Clean all the oil from the surfaces.... spray a coat of HiTack inside the boot and on the nipple and let them set for a few minutes.... Assemble as normal. A hose pick will be required for disassembly but it wont be impossible.... Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted August 19, 2006 Author Share Posted August 19, 2006 I tried the High Tack method. I determined that since the product does not completely dry hard it actually acts like a lubricant. I also discovered that when it gets hot, and the CAC tubes get very hot, the High Tack softened. I am referring to the spray in case you are using something different. So here's where I left off. Since this is my first shot at the truck I really have no idea when the over boost condition was actually repaired assuming there actually was one. I looked at the blue connector tube and decided that it was distorted from coming off so many times. I got a new tube, I scuffed-up the turbo and duct with some emery cloth and Brakleen. I torqued the clamps to 9 lb/ft and marked the edges with a marker to help identify ANY movement. I got it hot and road tested it, so far so good. Before I left and it cooled I re-torqued the clamps which did loosen a little. I'll do the same a few more times on Monday and see what I have. /forums/images/%%GRAEMLIN_URL%%/banghead.gif Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 20, 2006 Share Posted August 20, 2006 It's the spray that I am using... it's important to let the pieces sit and "flash off" since this stuff isn't anerobic (sp). At one point in time I had troubles with the boot coming off the CAC tube itself and this method cured all my troubles. Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted August 21, 2006 Author Share Posted August 21, 2006 I am satisfied that it's resolved. Since additional repairs were made after the blue connector hose had originally been replaced, and the connection failed over a dozen times or so I decided I was chasing my tail. At least I knew what the problem wasn't. My last post was the fix. But I have to be honest. Historically I never got out a torque wrench for these clamps and really have never had a problem. Using a torque wrench this time I learned several things. For one, what I thought was "tight enough" actually was not. The 9 ft/lb spec is tighter than it feels. Secondly, these connections will loosen up after getting hot, especially a new connector hose. So torquing is good advice and I know I have read this before. Kudos to those who spread that advice! /forums/images/%%GRAEMLIN_URL%%/thumbup.gif Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted August 23, 2006 Share Posted August 23, 2006 I've never used a torque wrench either but I allways clean both the hose and the fitting with brakeclean before I tighten the clamp with my air rachet. Funny you said that 9ft/lb is tighter than it feels, if you ever put a valve cover gasket on a 3.8L the spec is like 8 ft/lb you'ed swear the bolts gonna break off before the torque wrench clicks.. /forums/images/%%GRAEMLIN_URL%%/shrug.gif Quote Link to comment Share on other sites More sharing options...
Jim Warman Posted August 23, 2006 Share Posted August 23, 2006 Haven't used a torque wrench yet (but I'm getting more and more anal every day).... I usually snug the boot clamps down just enough for the OD of the clamp to feel flush with the boot when I run my fingertip over them.... right or wrong, it is working so far... Quote Link to comment Share on other sites More sharing options...
Torqued_Up Posted August 23, 2006 Share Posted August 23, 2006 I show 30 PSI at the duct and 24 at the manifold and the MAF reading matches with 24 PSI. So I measure a difference, or a restriction of 6 PSI through the after cooler. The HotLine thinks that's too much.I think a lot more of the Hotline these days but in this case I think you are measurements reflect more than restriction. What does the cooler do? It cools the compressed air and cooling condenses the air causing a slight pressure drop. I would expect there to be a pressure difference. I have just never heard of anybody doing this. You were actually able to thread the thin CAC tube? Quote Link to comment Share on other sites More sharing options...
Keith Browning Posted August 23, 2006 Author Share Posted August 23, 2006 Yeah, I threaded it for 3/8 PFT and I used one of the test fittings from the Ford gage bar tester kit. It threaded in, and tightened. When I was done I had my parts dude get me plug and I sealed it up nicely and it looks like it belongs there. Well, at least it doesn't look half ass though another tech somewhere someday will look at it and say "WTF?". /forums/images/%%GRAEMLIN_URL%%/cool.gif Quote Link to comment Share on other sites More sharing options...
eastendpowerstroke Posted August 24, 2006 Share Posted August 24, 2006 Well, at least it doesn't look half ass though another tech somewhere someday will look at it and say "WTF?". /forums/images/%%GRAEMLIN_URL%%/cool.gif Yeah someday some other tech will see that and say "This guy musta had some halfassed nitrous system F*&K THIS GUY LETS CANCEL HIS WARRANTY" /forums/images/%%GRAEMLIN_URL%%/rofl.gif Quote Link to comment Share on other sites More sharing options...
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