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Author Topic: How to tell if turbo is going bad?  (Read 6003 times)
belfert
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« on: September 02, 2007, 12:11:06 AM »

I did a search on turbo here and didn't find an answer on this.  How do I tell if my turbo is going bad?

I had the air intake off the turbo today so I spun the compressor wheel.  Someone said it should spin a long time and mine stops pretty quickly.  Also, there is some side to side play in the shaft.  I had to remove my charge air cooler to remove the radiator and didn't see more than a smidgen of oil in the pipes.

Can anyone recommend a source for a rebuilt turbo if I need one?  Mine is .80 AR M24 and is small for a Series 60 turbo since I have an 11.1L S60.  Most Series 60 turbos like on Ebay are for bigger S60 and have ARs of over 1.

Will I see better performance with a new turbo if mine is going bad?  I don't want to replace the turbo unnecessarily particularly in light of just spending $2,000 on radiator and water pump.
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luvrbus
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« Reply #1 on: September 02, 2007, 06:34:04 AM »

Brian, if your compressor wheel has nicks and is getting sharp on the blades it may be time to look at a rebuilt turbo if there is no oil and it spins free i would not worry about the side play i got a rebuild from a DD that had more play than the one i took off
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TomC
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« Reply #2 on: September 02, 2007, 10:00:29 AM »

You should have NO end or side play in the turbine wheel.  DO NOT RUN IT AGAIN! Get a rebuild kit or just replace the whole turbo.  It the turbo wheel goes or starts grinding the housing, you're not going to like the results.  Hopefully I come over loud and clear!  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
luvrbus
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« Reply #3 on: September 02, 2007, 10:33:10 AM »

Brian, buy you a dial indicator and check it if you are between .0003 and .0008 you will be fine so says the DD book
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belfert
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« Reply #4 on: September 02, 2007, 02:43:35 PM »

You should have NO end or side play in the turbine wheel.  DO NOT RUN IT AGAIN! Get a rebuild kit or just replace the whole turbo.  It the turbo wheel goes or starts grinding the housing, you're not going to like the results.  Hopefully I come over loud and clear!  Good Luck, TomC

I'm getting conflicting answers here.  The first poster who replied says not to worry about play and you say not to run the engine period with any play in the turbo.  I certainly would not want the turbo to come apart as the metal could damage or destroy the engine.

The best answer to see if the turbo is working properly would be a boost gauge, but I don't have one.  The guys at the local Detroit dealer didn't have a good answer as to how to tell if a turbo is bad except a boost gauge.  They said a reliabilt replacement would be $900 from Detroit.  Of course, they say I should only use a Reliabilt as any Freightliner or Detroit dealer could replace it under warranty.  For the few miles my bus gets compared to an OTR truck I think a third party rebuilt would be fine.

What type of local shop could rebuild my existing turbo or at least check mine out?
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luvrbus
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« Reply #5 on: September 02, 2007, 03:29:52 PM »

Brain,if you have a Cat dealer close take it to them to check some DD and Cats are the same i don't know what model you have but if the DD Dealer doesn't know how to check it without a boost gauge i would look for some other place to buy



















« Last Edit: September 02, 2007, 03:38:22 PM by luvrbus » Logged
luvrbus
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« Reply #6 on: September 02, 2007, 03:56:53 PM »

Brian try this page if you haven't already and it will tell you how to check your turbo www.turboparts.info
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TomC
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« Reply #7 on: September 02, 2007, 07:17:05 PM »

Brian- just remember that the turbo up at speed is turning in the 20,000rpm range.  Would you want loose bearings on that?  You can buy a cassette bearing replacement.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
Sojourner
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« Reply #8 on: September 02, 2007, 08:41:23 PM »

Someone said it should spin a long time and mine stops pretty quickly. 

That quote was referring to just after de-throttle the engine while under load plus consant hot oil flow thru its turbo bearing (make it spin more freely). Otherwise a free turning turbo can be turn by finger. Stop pretty quickly is normal.

Parts counter person are not mechanic....they are usually not knowledgeable...they just parts seller.

Always ask service man for permission to speak to a expert on what ever subject.....you should get answers.
The bigger truck repair center usually the better answers.

Like what TomC quoted plus check for carbon build up, wet coat of oil film in turbo air outlet (leaking seal).

FWIW

Sojourn for Christ, Jerry
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JohnEd
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« Reply #9 on: September 02, 2007, 10:03:04 PM »

LVR,

I think the argument stopped when you quoted DD with a max end play of .0008 and a min of .0003.  You need a dial indicator to detect that little movement.  If there is perceptable end play a rebuild would seem in order.  Tom's advice of NO RUN was prophetic.  $10K for the rebuild would seem to provide ample incentive.

Isn't this inspection a PM?  Who that has a turbo has NOT opened their intake up and inspected for this condition?  How often does it happen that a turbo is lost and it does not do severe damage to the engine?  I know the chunks have to go through the blower but I think that the blower would not "filter" the chuncks as it would add to the debret.  Was that a rant? Huh Grin

John
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donnreeves
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« Reply #10 on: September 03, 2007, 05:50:35 AM »

You can feel a very small amount of play even on a new turbo. You can use a cheap air gauge from a plumbing supply for a temporary boost gauge. Just run an 1/8" air line from the housing below the turbo the the drivers compartment. It can even be taped to the outside of the bus. On mine the play in the old turbo didn't cause a drop in max boost, but the time to spool up was more than doubled. Matting the throtle from a standstill, it went from 7 seconds with the old turbo to 3 seconds with the new one, with a coresponding decrease in smoke. Unless you can find someone with the experiance to feel the sideplay, the best bet is to put a dial indicator on it.   Donn
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belfert
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« Reply #11 on: September 03, 2007, 07:53:10 AM »

I looked in the phone book and there are two listngs under turbochargers.  One of the companies rebuilds turbos.  I'm going to call them in the morning to see if they can check out my turbo and rebuild it if necessary.

And no, the suggestion that the turbo ought didn't come from here, but rather from a mechanic I know, but he is out of town right now.
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Sammy
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« Reply #12 on: September 03, 2007, 11:16:37 AM »

If the turbo is bad you will know it.
Smoke, no power or low power,oil residue ,etc.
The turbo shaft will  have a very small  amount of "play" because there will be a film of oil between the turbo shaft and bearing while engine is running.This is also why it is recommended to let your engine idle for a minute or 2 before shutting it down - to let the turbo speed slow down with oil still flowing to the bearing.The engine oil fills this very tiny gap between shaft and bearing.
The bearing is brass or bronze, looks like a bushing. It's pressed into the turbo housing and held in place with a snap ring.I have rebuilt turbos for transit buses - AR and Garrett types.
If you were not experiencing any types of the symptoms I mentioned above, I would leave it alone.
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tekebird
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« Reply #13 on: September 03, 2007, 12:17:21 PM »

Brian, don't give a company the opportunity to take you over the coals.

if your Turbo was bad it would be obvious in performance.
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larryh
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« Reply #14 on: September 03, 2007, 12:51:48 PM »

Brian don't let the doom sayers influence your thoughts. did you have a reduction in performance? did you have oil soaked tubeing?

you have to have some end play and a little feelable play otherwise when that hot exhaust started expanding things when going through turbo at right at 1400 degrees it would freeze up on you from expansion.

If your answers to above questions were no then put back together and drive that sucker.

LarryH 43 years experience in the heavy equiptment fieldoy that dinausour you got too bad not a GMC LOL
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