Whistling / squealing noise 9400i

Blown exhaust gasket, either manifold or turbo flange. If you have an ISX with EGR also look for soot leaks around the EGR valve. Failed gaskets here make that noise too.

 

Leaking air-to-air cooler or an intake leak anywhere between the turbo and intake valves. Don't forget the air compressor, sometimes intake boost leaks out of the air dryer's purge valve when the spring inside it gets weak.

 

Like the above stated, check everything from the turbo charger to the intake manifold. That includes all the charge intake air and it's distribution path including hot and cold boots, CAC (charge air cooler) and another area is look carefully is intake manifold for cracks or leaking intake gaskets. Today's engines use aluminum air intake manifolds and they DO crack as mine did. $500 for a used one plus cost to install it. If it's just a blown intake manifold gasket to engine block, just replace them with new ones and your good to go. Best way to test these theories is a Windex spray bottle filled with liquid dish soap and water. Simply start engine and spray all air connections from turbo side of engine, around the front of the engine at the charge air cooler radiator, then onto the intake manifold side of the engine and spray that cold side liberally. When huge bubbles start forming, then you've found your problem. More than likely you either find bad intake manifold gaskets or a cracked intake manifold. These things happen, welcome to trucking 101.

 

There is a line running from the turbo about 5/8 diameter arou d the back of the engine to feed the air compressor. At the back of the engine is a short piece of rubber hose to a sorb vibration. It fails and makes the. Noise u r describing

 

Here is one important item I want you to check in addition to above suggestions. Aluminum air intake manifold have a habit of cracking. Start up and warm engine, then run engine at high rpm's and use a spray bottle with a soap solution. While rpm's are high, spray intake manifold all over including area where manifold gaskets mount to block. If you do not find bubbles, then start working way towards turbo from intake manifold spraying cold and hot tubes, rubber boots, air-to-air radiator all the way back to turbo. I believe you will find your problem in the intake manifold but it could also lead to a leak in your Blue and Orange colored boots. Just spray soapy solution liberally until you find the air leak. If leak is not found in the cold air intake system, then start spraying the exhaust side manifold, including manifold gasket area and all area's leading to turbo. But my hunch is your problem will be found on air intake side of system particularly the intake manifold gaskets feeding cylinders number 5 and 6 in the back of engine. If you find a cracked intake manifold, you cannot fix this. You must purchase a new or used manifold and replace with brand new gaskets.

 

I have a 2010 Prostar and I'm having a similar issues as far as the squealing noise. Did you ever identify the problem your truck had? I had a local shop look at the truck several times and they keep saying its a belt and pulley issue. They've changed both of my belts and replaced all of my pullys and tensioner. The sound isn't happening as frequently and when it does it's for a shorter duration of time but the noise is still there.

 

Mine was bad turbo bolts. They replaced bolts and new gaskets all was well.

 

My brother has a 9200i ( International ) with virtually the same problem, but with one difference. Every time, without fail, when this problem occurs, the voltmeter ceases to indicate it's typical 13.5 V, immediately dropping to 12V. He has changed the belt and belt tensioner. There was no change. His diesel tech changed the charged air cooler. Still, there was no change. Do you think that a previous post that mentioned the turbo bolts may be applicable in this case ?

Thanks for any help ! My brother & I appreciate your thoughts.

Franklin Thomas

Savannah, Georgia

thomastv@bellsouth.net

912-354-7003