cac hose issue

craneman · **Posted:** Tue Dec 17, 2019 8:46 am

im having an issue with my cac hose blowing off and sending the crd into limp mode. I have tried several fixes, from new hose to glue all to no avail. does anyone here have a clue where to go next? the truck will run for about 15 minutes or until it is up to normal temp and then "pop" and im done. driving me nuts. this does have the Sasquach hose kit on it, which, consists of a 2-1/4 x 2-1/2 reducer to a metal elbow to a 2-1/2 x 2-3/4 hose to the cooler. the first time it blew there was a bunch of oil in the lines. cleaned it all out and reinstalled. only went a few miles and it blew. so I figured that I needed better clamps, no help. then a replacement reducer and clamps, no help.
im thinking there might be restriction in the cac that is causing great pressure but not sure.

mike

APC9199 · **Posted:** Tue Dec 17, 2019 12:10 pm

The MAP sensor would let you know if there were some large restriction in the CAC system. This is highly unlikely.

Is it always blowing off at the Sasquatch connection? If so, that is actually a good thing, since the plastic connections on the CAC itself are relatively fragile and don't take much clamp force to crack. Remove the hose completely, spray it with carb cleaner or brake cleaner and wipe ALL of the oil off of it. Remove the elbow portion of the intake and give it a good roughing up with some aggressive scotch brite (purple). Clean it with the same cleaner used to clean the hose, after re-installing it. Borrow your wifes/gf's hairspray, or go buy some of the cheapest you can find, and spray the outside of the elbow with it. Immediately slide the hose onto the elbow PAST THE DEBOSSED RING near the end of it. Your clamp needs to be positioned on the engine-side of that ring and tightened fairly tight. There should be 1/4" to 1/2" of CAC hose showing after the clamp. The Sasquatch elbow is much more rigid than the CAC connections, so go until you see the silicone hose bulging on either side of the clamp, but not so much that you shear it off completely. The elbow should handle as much force as you can put on it with the provided worm clamps.

Let us know if it still pops off after that!

WWDiesel · **Posted:** Tue Dec 17, 2019 2:14 pm

Had similar problem on my Dodge Cummins with 40 psig boost, had one connection point kept blowing off out of four.
Solved it by replacing all the rubber hoses with much better quality and thicker silicone hoses along with using new spring loaded constant force spring loaded "T" clamps and coating all mating surfaces real good with 3M spray High Tact 76 Glue. See picture.
Have not blowed a hose off since doing this!

If you still have rubber OEM boost hoses, get some good quality new silicone boost hoses like Samco.
As APC said, clean inside of hose and metal tube connection points real good with carb or brake cleaner (Acetone is even better) and sand or rough up the outside of metal pipe some.
Coat both mating surfaces with spray glue and use a good quality "T" type clamp. Tighten down until you see the hose start to very slightly "bulge" on both sides of the clamp. Allow it to dry for several hours or overnight before driving. It should solve your problem.

Note: Worm type screw clamps are not good clamps for boost hoses!

craneman · **Posted:** Tue Dec 17, 2019 2:53 pm

thanks for the input. I pretty much have tried all of the above. predominately it blows off at the very first joint. not sure of the name of the item, turbo outlet? on the drivers side of the engine. metal tube looking down to the road. that is a 2-1/4 pipe that the reducer hose goes on. believe it or not yesterday I put a new constant torque clamp on it as tight as I could. thought it was solved and after a 10 minute test drive, bam. I have a can of 3M 76 adhesive that I got today so im going to give it a shot tonight. will also ruff up that fitting to give it some purchase.
what I don't understand is, this thing has 156000 miles and now all of the sudden im having this issue. what has increased the pressures enough to force this hose off of the fitting? something is totally out of balance.
will advise tomorrow with my results.

Mike

WWDiesel · **Posted:** Tue Dec 17, 2019 3:31 pm

A faulty MAP sensor could be causing the turbo to over boost pressures. Do you have a boost gauge?
May want to replace the MAP sensor with a new one, they are only a little over $20 bucks if you use the GM part number.
GM 55206797 :google:

flash7210 · **Posted:** Tue Dec 17, 2019 3:35 pm

I had this problem several years ago while on a cross country trip along I-40.
To me, the problem seemed to be the wide band clamps that came with the kit.
They just couldn’t get enough pinch to hold the silicone reducer onto the flange on the engine side.
So while on the side of the highway, I swapped the t-bolt clamp for a regular screw type clamp. Tightened that screw as hard as I possibly could. Didn’t pop off ever again.

Since then I’ve replaced the Sasquatch aluminum elbow with my own custom aluminum pipe and silicone elbows/reducers. Still using the same cheap screw type clamps. Never popped off even at 30psi.

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

FWIW, a couple respectable turbo builders in SoCal also recommend against t-bolt clamps. They might provide more clamping force than a worm-gear type clamp, but in most applications they end up being misused to cover up some other problem (size mismatch, engagement issue, contamination), and then cause problems of their own. Here's an article about the scenario:

https://amsperformance.com/wp-content/u ... _Clamp.pdf

Take a look under the hood of any modern turbocharged car (which is basically all modern cars) and you won't find a single t-bolt clamp. Even on things like the AMG 2.0l, which runs 26psi from the factory. Unless you're in the 3 bar club, a t-bolt clamp should not be necessary.

Edit: One other thing worth mentioning: You should NEVER use cheap parts store worm-gear clamps on silicone hose. Or, really ever at all. Use a good clamp, with a solid back, one-piece gear housing, and rounded edges. Sometimes called "ABA clamps" for the company that primarily makes them. Like:

https://www.driftmotion.com/product-p/dm3017.htm

craneman · **Posted:** Fri Dec 20, 2019 8:46 am

update, I have refitted the hoses, using the 3M glue. I happen to work for a generator company and have access to all types of clamps. in fact im a parts manger so I know them pretty well. that being said I am using a constant torque clamp not a t-bolt, we also carry silicone specific clamps with smooth band. I went with the CT because I think it will hold the best.
got a new MAP sensor coming in today and will install that and give the key a turn. im just not understanding why there is now so much pressure to "blow" the hose off when there has not been an issue before. what causes over boost on the turbo?
could there be something that has changed the amount of pressure that is now going through these hoses that makes them explode? more questions than answers for sure. will let you all know how it goes tomorrow.

flash7210 · **Posted:** Fri Dec 20, 2019 9:05 am

If it is overboost a code should be set.
About 22psi is the max for a stock tune.
But if there is a problem with the MAP sensor then there is no way to know what actual boost is without a mechanical boost gauge.

APC9199 · **Posted:** Fri Dec 20, 2019 9:48 am

craneman wrote:

update, I have refitted the hoses, using the 3M glue. I happen to work for a generator company and have access to all types of clamps. in fact im a parts manger so I know them pretty well. that being said I am using a constant torque clamp not a t-bolt, we also carry silicone specific clamps with smooth band. I went with the CT because I think it will hold the best.
got a new MAP sensor coming in today and will install that and give the key a turn. im just not understanding why there is now so much pressure to "blow" the hose off when there has not been an issue before. what causes over boost on the turbo?
could there be something that has changed the amount of pressure that is now going through these hoses that makes them explode? more questions than answers for sure. will let you all know how it goes tomorrow.

First off, I have to apologize for saying "worm clamp" earlier. That is NOT what I meant. I have been using the clamps that come with the Samco hose kit, which are similar to the ones on the right in the AMS link that thesameguy posted. I do not and will not use traditional style worm clamps on any of my turbo hoses. I don't even like using them on other hoses under the hood, to be honest.

IF...IF your turbo is actually producing more boost than it used to, it could be as simple as the MAP sensor being bad. It is what your ECU uses to measure the boost being produced, and to adjust the vacuum being applied to the actuator to move the vanes and adjust boost up or down accordingly. In fact, if your boost is too high, that sensor almost HAS to be bad, otherwise you would be getting an overboost code. All of the quality boost hoses on the market are rated to handle all the boost that an OEM CRD can throw at them. Several people are running higher than standard boost and have not seemed to have much trouble with their hoses. The MAP sensor is definitely the first place to start diagnosing this.

WWDiesel · **Posted:** Fri Dec 20, 2019 11:04 am

craneman wrote:

update, I have refitted the hoses, using the 3M glue. I happen to work for a generator company and have access to all types of clamps. in fact im a parts manger so I know them pretty well. that being said I am using a constant torque clamp not a t-bolt, we also carry silicone specific clamps with smooth band. I went with the CT because I think it will hold the best.
got a new MAP sensor coming in today and will install that and give the key a turn. im just not understanding why there is now so much pressure to "blow" the hose off when there has not been an issue before. what causes over boost on the turbo?
could there be something that has changed the amount of pressure that is now going through these hoses that makes them explode? more questions than answers for sure. will let you all know how it goes tomorrow.

If the MAP sensor goes bad and is reading less pressure than the turbo is actually producing, the ECM would be calling for more boost due to the lower signal it is receiving and this would overdrive the turbo and actually could overspeed it which is very bad for the turbo. This would also put additional strain on all the boost hoses and fittings.
Over-pressure would also be very bad for the plastic tanks on the CAC.
But the only true way to know for sure is a mechanical pressure gauge reading boost pressures across the entire operating range.

craneman · **Posted:** Fri Dec 20, 2019 12:41 pm

thanks, will take that into consideration. will dig about here and see what others have done to add the gauge.
Mike

craneman · **Posted:** Mon Dec 23, 2019 10:05 am

update, FIXED, I hope. put the new MAP sensor in and fired her up. ran fine. used it all weekend and again this morning on my drive in. ran fine. fingers, crossed, a simple $22 part solved all my headaches.
thanks for the help on this forum. sure is a blessing.
Merry Christmas to all of you here
Mike

WWDiesel · **Posted:** Mon Dec 23, 2019 11:24 am

craneman wrote:

update, FIXED, I hope. put the new MAP sensor in and fired her up. ran fine. used it all weekend and again this morning on my drive in. ran fine. fingers, crossed, a simple $22 part solved all my headaches.
thanks for the help on this forum. sure is a blessing.
Merry Christmas to all of you here
Mike

TKB4 · **Posted:** Wed Jan 01, 2020 8:46 pm

And a happy new year!

cac hose issue

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