LB7: Boost leak..? How to find

[John Noonan]

2003 6.6 Duramax, 77K miles.

All stock other than a Hypertech programmer.

Truck started to have a"whine" at 2,500 rpm and above.

Dealer told Michelle (my girlfriend and owner of the truck) it was either the intercooler or the "Blower:rofl:" and that to replace the intercooler it would be 500.00 and after they replaced it and it still made noise/whine then they would need to replace the "Blower"...After the oil change was done I went to pick the truck up at Delillo Chevrolet and the service guy that had told me the intercooler or blower needed replacing was not present.

I did not inform him that the truck came with a turbo, I had asked him about checking the intercooler for leaks and he insinuated they just replace parts and they only have one guy that knows about diesels.

I took the truck out of the dealer and declined to pay the $ 110.00 they wanted to determine what the leak was, when I got the truck back I could tell from the two hand prints all that had been done was the "technician placed his two hands on top of the Black plastic engine cover as I could see the two prints.


I have tightened up all the hoses and confirmed it only happens under a load (I have three 500 plus HP motorcycles I land speed race at Bonneville and El Mirage) however is there a particular area a boost leak starts from?

I placed a boost gauge inline from the compressor side to the wastegate and it maxes out at 1.2 bar however I thought it would make more, the truck still runs great however I have the September El Mirage event coming and I want the truck in 100% shape as I have a 36' fifth wheel we tow.

Any help?


I am in Huntington Beach CA FWIW

 

[John Noonan]

Also, can I bypass the intercooler with a hose from the compressor side to the intake for just a quick run to see I can rule out the intercooler?

John

 

[Whitetail Addict]

Check for rub through on the intercooler tube above the steering box...steel steering line rubs through the aluminum intercooler tube.

 

[Turbo Buick 6]

The best way is to cap off the boost tubes and use low pressure with an air compressor and listen for leaks. If you do a search I belive there is a writeup on how to do this.

 

[sweetdiesel]

Also, can I bypass the intercooler with a hose from the compressor side to the intake for just a quick run to see I can rule out the intercooler?

John

you could just pressurize it that way to see if its the boots ,tube or IC
get some caps from home depot and use your compressor

Are you not getting the boost you useally do?

 

[WolfLMM]

Take all boots off and clean them, reinstall. See if problem goes away or gets better.

You can get windex and spray the crap out of everything and just have your GF brake boost the truck and look for bubbles, be careful though.

 

[John Noonan]

Check for rub through on the intercooler tube above the steering box...steel steering line rubs through the aluminum intercooler tube.

Just checked and could not find any damage or dents from the steering shaft hitting..looks like it's about 1.5 inches away.

Thank you for that however as I never would have thought about it.

I will get a better look tomorrow with a mirror.


J

 

[John Noonan]

The best way is to cap off the boost tubes and use low pressure with an air compressor and listen for leaks. If you do a search I belive there is a writeup on how to do this.

Yes this will be on the list I just have to get some caps/plugs..

Thank you,

John

 

[John Noonan]

Take all boots off and clean them, reinstall. See if problem goes away or gets better.

You can get windex and spray the crap out of everything and just have your GF brake boost the truck and look for bubbles, be careful though.

My luck she will have an "accident" while I am under the hood...If I go she gets it all...I did power brake it today and the rear tires started to spin before I heard the leak.
I did pull the clamp at the compressor side and pulled the hole off, looked "normal" and I tightened the other clamps however I did not pull them I just wrenched them down a bit.

Anyone know if it is common to have a leak in a factory cooler?

Also the boost was 1.2 bar about 17.6 PSI, what is normal under full "power"


Thanks and keep the assistance coming please..


John & Michelle

 

[Whitetail Addict]

Just checked and could not find any damage or dents from the steering shaft hitting..looks like it's about 1.5 inches away.

Thank you for that however as I never would have thought about it.

I will get a better look tomorrow with a mirror.


J

Just wanted to clarify and maybe save some headaches.

It is not the steering shaft but the power steering fluid line going into the steering box that rubs the intercooler piping. It will be on the bottom of the intercooler pipe almost against the frame...it is easier to check it if you pull the skid plate and look up from the underneath, or you can feel around the bottom of the pipe but it can be a tight squeeze. You may have to pull up on the pipe to check it thoroughly as the pipe will rest on the line and could (in theory at least) seal.

On edit...on stock tuning I saw a max of 20psi reading from the intake manifold.

 

[John Noonan]

Just wanted to clarify and maybe save some headaches.

It is not the steering shaft but the power steering fluid line going into the steering box that rubs the intercooler piping. It will be on the bottom of the intercooler pipe almost against the frame...it is easier to check it if you pull the skid plate and look up from the underneath, or you can feel around the bottom of the pipe but it can be a tight squeeze. You may have to pull up on the pipe to check it thoroughly as the pipe will rest on the line and could (in theory at least) seal.

On edit...on stock tuning I saw a max of 20psi reading from the intake manifold.

I understand, I will look first thing in the morning when I can see and also make a little noise..any chance of the wastegate going bad? I don't think it is however I plugged the compressor side hose and then stuck 20 psi to the wastegate and left it there, the truck ran like a dead dog since the boost was just running out the gate however I never heard the sound while doing that.

John

 

[John Noonan]

Just wanted to clarify and maybe save some headaches.

It is not the steering shaft but the power steering fluid line going into the steering box that rubs the intercooler piping. It will be on the bottom of the intercooler pipe almost against the frame...it is easier to check it if you pull the skid plate and look up from the underneath, or you can feel around the bottom of the pipe but it can be a tight squeeze. You may have to pull up on the pipe to check it thoroughly as the pipe will rest on the line and could (in theory at least) seal.

On edit...on stock tuning I saw a max of 20psi reading from the intake manifold.

Well since I work at a home office I just spent my "break" working on the truck, I did remove the inner fender liner and then I went and removed the pipe completely, I looked at it and I see the rubbing/chaffing marks however it is not all the way thorough however upon reassembly I will wrap it and make sure to protect it a little longer.

Later I will remove the other side or get a better look at it (does it come out as easy as the drivers side pipe) as the sound seems to be coming from the passenger side when I am driving.

Thank you for the help so far..


John

 

[John Noonan]

Well today between calls I removed the rest of the intake system and both Aluminum tube from the intercooler.

I went to Home depot and found some plugs that fit right in the end of the hose from the intercooler. I tapped a fitting for my air compressor on one end and left the other sealed.

I then allowed my glue to seal since I was not planning on reusing these new "tools" I just made and then I went on to check the intercooler.

I found NOTHING...no leak up to 25psi..so now Michelle's truck is all apart and I have no idea where th leak is?

Do the wastegates ever go bad and leak?


Anyone..?

Thanks.

John

 

[WolfLMM]

They can go bad. Your charger may be due.

 

[Turbo Buick 6]

Don't know if the waste gate would be making it whine, maybe y-bridge gasket Hows the shaft play on the charger?

 

[John Noonan]

Don't know if the waste gate would be making it whine, maybe y-bridge gasket Hows the shaft play on the charger?

With the intake pipe off I can see the shaft however have not taken it even further apart to get to the shaft, I am trying to do this in between phones and short breaks and then today after work.

When the Hypertech controller with the level three program installed the truck of course runs better and hauls the mail for a stock truck, during that time you cannot hear the "leak" as easy as it spools so fast and you are at 90mph before you know it.

When the stock tune up is plugged in the turbo spools slower and the leak sound is MORE apparent as you are going slower and taking longer to build boost.



Their is no leak sound when free revving at 3K rpm unless the engine/turbo is under a load so that tells me it is on the pressure side and with the turbo making about 18 psi (with a gauge I have no Idea if it is accurate) it is only heard when under boost and seems more noticeable on the passenger side of the engine compartment when driving.


Now that the intercooler is ruled out I am looking for any other ideas or tests before she (Michelle) decides to get get rid of it and get a new Ford F450

John

 

[John Noonan]

Help ! ! !

So back to me and our problems...

So I confirm the intercooler is not leaking by making these adapters to fit in to the intercooler hoses and pump in 25psi and let it hold for one hour.

The nasty looking stuff is cement glue I used to insure no leaks would come from the two pieces I screwed together to make each intercooler plug.

No leaks.

So then I start looking at everything else to see if I can find where the gremlin is that leaks..I end up pulling the grill, headlights inner fenders everything in my way to get to the top of the engine a bit easier as well as to install the Aluminum tubes back from the intercooler.

I end up finding a small vacuum hose that is split that connects to the thing? in the last picture (what is the thing the screwdriver is resting on) , I cut off the bad end and zipty the hose, reinstall everything and still have the sound of a pressure leak.

Who can sort this for me locally in So Cal?

Thanks,

John

PS, Sorry for the big pictures..I hope they have enough detail in them :rofl:


J

 

[McRat]

You look like you've tested pretty well, and found no leaks.

If the truck is making good boost (about 20 PSI stock tuning), and you can't see damage when you look inside the compressor inducer (it will start to score the hsg), it's probably not turbo system related.

Any other symptoms for the noise?

 

[McRat]

MK Smith Chevrolet (Chino) has about the best Dmax guy anywhere. Robert Miller.

 

[John Noonan]

You look like you've tested pretty well, and found no leaks.

If the truck is making good boost (about 20 PSI stock tuning), and you can't see damage when you look inside the compressor inducer (it will start to score the hsg), it's probably not turbo system related.

Any other symptoms for the noise?

Pat,

I did take a marker and place Black marks on the impeller and also the housing to see if it leaves any marks from hitting, what is the part I am asking about?

Thanks again and keep it coming I am frustrated as he&&


J