Why would an enigne chew through turbo's?...

[Rawze]

Why would an enigne chew through turbo's?...

- This is the question that Yiyto's turbo shop (Griffin, GA) has asked me, and what to look for on the engine to prevent it after a turbo gets rebuilt/replaced.

I am posting this here for myself, and for others to join in and give some suggestions, opinions, etc.. so that he can make a list o f things to check for on the engine/truck when someone gets a turbo replaced, to prevent a repeated failure.

Here is a list of causes I got off the top of my head so far...

== #1 first and foremost ... the typical 90%+ of BAD DELETE PROGRAMMING that is seen time and again around here. Simply having the de-mandate programming reviewed to see if the turbo (and the rest of the ecm) has been properly re-programmed will prevent this.

== Deleted enignes where there is no block-plate between the exhaust manifold and turbo. OR. Engine with a whole lot of miles on it and the egr cooler is getting clogged ... Carbon builds up in the egr cooler after several years, it hardens, and spits back out randomly as hard chunks ... destroying the turbine blade(s) and/or hanging up the VG mechanism as they go thru the turbo. This typically causes repeated turbo failures. - I have seen people go thru 3 or 4 turbo's in a row in short succession because of this before they realize this is the actual problem.

== Very dirty intake filters. Causing over-spooling of the turbo all the time. Dirty intake filter makes the turbo speed up and work harder to get the right amount of air at the intake manifold.

== Aftermarket CAC unit. <- Some brands (like duras$it and others) of after-garbage charge air coolers are VERY RESTRICTIVE, and cause the turbo to speed up and work harder to get the right boost st the intake. This is another quite common problem that i have seen.

== CAC and/or other boost leaks on the intake. Loosing boost pressure due to bad CAC, bad boots on the intake, etc.. cause the turbo to speed up and work harder to get the right boost st the intake.

== Oil flow restrictions thru the turbo and top end of the engine. - It is VERY EASY for the turbo to get starved of oil and/or for it to bleed oil into the CAC or exhaust if there is any kind of crank case pressure buildup in the engine at all. Having a clogged up crank case filter, or one that cannot keep up with blo-by on an older engine will certainly take out a turbo, or cause it to bleed oil, and also cause the top-end of the engine ti run dry, chewing up overhead cams/rockers, etc.

== ANY type of exhaust restriction... deleted or not. On a deleted engine, some moron only drilling holes thru the elements instead of gutting all of them 100% to the bare metel. Morons who think they can ignore the SCR unit like a fool (after a delete) and not hollow it out 100% properly as well. - AND/OR-- Deleted or not... if the decomp tube gets clogged up partially due to seeping def fluid (known as the volcano problem listed here: http://rawze.com/forums/showthread.php?t...07#pid1807

== Excessive positive pressure all the time at the intake on non-deleted enignes.. causing the infamous 'turbo cough' when you get on it hard, or sitting there at idle. This happens when sensors are reading badly and/or the egr curcuit and sensors are full of soot. This also happens with bad delete programming where things were not shut off properly.

== bad IMAP, EGR delta-P sensor (of clogged passageways for Delta-P), and other egr-tune-up /egr soot buildup related problems.

== excessive heat form someone turning up the power.. and or exceeding the turbo's flow ratings (due to jacking the power above turbos ratings) .. and there is not enough cooling around the turbo externally to wick it away.

== heavy haul applications where the wrong turbo was used (non titanium model) .. and/or where there is simply not enough air flow around the engine and trubo to keep up with this type of torture.

== RV and buss applications where there is simply not enough air flow around the engine and turbo to keep up with this type of torture. This especially on RV's where they tend to jack the power all the way up even from the factory.. to 'brag about its power and sell more units'.

That is what I got so far just thinking about it ... can anyone think of more scenarios?...

[marek4792]

Not turbo exactly, but directly upstream I had an injector leaking between pulses had costed me atleast 3 manifold center sections before I figured it out, by snapping the throttle with the manifold off and having white smoke pour out of the one port.

[Volvo8873]

My turbo went on my last truck I owned. My boost gauge had a flutter to it at full boost. Went almost 4 years like that. Realized looking back it was probably damaged from carbon breaking off or something else but whatever it was it was not ever right from the get go. So just thing for others should take note off if they have similar problems.

[Yauchout]

one of the most common denominators i have seen is not giving the turbo time to cool before turning off the engine especially after a fully loaded pull i see many do this in this west virginia town i deliver to a lot it has a 7% just before dropping into town then you have to run the jakes all the way into town after iv watched them over and over again pull into a pull through space and immediately kill the engine. I have had to let mine idle for nearly 20 minutes in july before after to get the egts in the 350-375 range after the 3 hard pulls going into that town on us 48 unfortunately my original vgt turbo and actuator only made it to 800K ish miles and the exhaust wheel broke off.

[tree98]

On the X15 in particular some have a problem with eating speed sensors, they get wonky and see the turbo spinning even if the engine isn't running.The ECM not knowing that the speed it's seeing is wrong makes incorrect adjustments i guess and you end up with codes for high turbo inlet temp. Demandate solved the problem entirely but before that I replaced the speed sensor 3 times in 2 years.

[Rawze]

(02-13-2025 )tree98 Wrote:  On the X15 in particular some have a problem with eating speed sensors, they get wonky and see the turbo spinning even if the engine isn't running.The ECM not knowing that the speed it's seeing is wrong makes incorrect adjustments i guess and you end up with codes for high turbo inlet temp. Demandate solved the problem entirely but before that I replaced the speed sensor 3 times in 2 years.

Good point ... They tend to melt or go bad due to lugging the engine at low rpm and high torque. Not enough air flow around the outside of the engine, and the intake side of the turbo gets real hot, melting the speed sensor. Trucks that are geared too tall for the application (or Volvo's with their terrible under-hood air flow) tend to go thru turbo speed sensors for the X15's.

[JimT]

What's the typical life expectancy of a turbo that HAS NOT been abused or obviously damaged as mentioned above? Same question for the actuators too. I'm specifically interested in the VGT for a cm2250, but would also be curious about other turbo's too. My turbo was replaced at some point before I bought the truck and I've logged over 400k miles personally. I haven't observed any indications that it's going bad, but I like to plan ahead whenever possible. The actuator appears original, but that too hasn't shown any signs of going bad, yet.

[tree98]

I would say 600k-800k miles on the turbo itself. The actuators these days only seem to last 300k-400k miles before they start to throw communication faults.

[Rawze]

Most VGT's that are not abused typically last between 400 - 600k miles. Actuator will last much Longer if you take it apart and grease it every 250k miles or so.