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Author Topic: How to tell if turbo is going bad?  (Read 6490 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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« 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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« 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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« 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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« 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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« 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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« 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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« Reply #15 on: September 04, 2007, 03:53:03 AM »

Brian, on ebay run a search for Detroit Diesel, you will be surprised what pops up!  There are usually all kinds of manuals on turbo's, I would get one they are cheap, in the meanwhile I'd listen to TomC's advice, it might save you some money!
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« Reply #16 on: September 04, 2007, 11:06:07 AM »

A turbo boost gauge is $25 on Ebay.  I don't know what affect running the tube 40 feet would have on the readings.  Would sure delay it though.

Dallas!  Where are you?  Somehow I am sure that one of your DD books has a number for PSI of boost at 1,800 rpm for a Huh?  That would take all the ruminations out of this and let those with a suspecion get on past that point without dumping uneccessarily cash.

Please,

John
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belfert
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« Reply #17 on: September 04, 2007, 12:26:13 PM »

I don't know that I am going to worry about the turbo right now.  Removing it would be a trick as the heat causes severe rust of the nuts holding the turbo to the exhaust manifold.  I really wouldn't want to snap off the studs going into the exhaust manifold.

There are not any real obvious problems with the turbo so I'll leave well enough alone I think.  It is unclear if the side play is normal or excessive.
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« Reply #18 on: September 04, 2007, 01:55:59 PM »

Belfert,

Lot of good sense in your decision.  On the other hand..... 

Those bolts come right off after heating them cherry red.  For future ref.   Long in the future, I hope.

I still want to know what the pressure should be.  Regardless of the end play, you, or anyone, should be able to verify that the turbo is putting out the proper pressure at a given rpm.  I have seen posts where one BN said he had 27 pounds and another said he never saw more than 22.  Obviously they have boost gauges.  I should think a boost gauge would be a required instrament so you could see the pressure falling off and know why you are smoking and dropping a gear on that certain hill and your MPGis in the toilet.

Hope Dallas gets home soon.

Thank you,

John
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"An uneducated vote is a treasonous act more damaging than any treachery of the battlefield.
The price of apathy towards public affairs is to be ruled by evil men." Plato
“We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light.”
—Pla
belfert
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« Reply #19 on: September 04, 2007, 04:14:12 PM »

It appears that there are electric boost gauges that have a sender at the engine.  I certainly would not want to run 40 some feet of tubing to a gauge on the dash.

Where would one hook up the sender for a Series 60 engine?  My F-350 with 7.3 engine I just cut a boost line and inserted a tee, but not sure there is such a thing on a Series 60.

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« Reply #20 on: September 04, 2007, 04:44:33 PM »

Brian

I think you have made a smart decision on the turbo. If you lose power and gets lots of smoke and can't pull a greasy string out of a goats back side then you might have a turbo going South.

Hate to see people spend money unwisely

LarryH
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Dallas
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« Reply #21 on: September 04, 2007, 06:04:26 PM »

Belfert,

Lot of good sense in your decision.  On the other hand..... 

Those bolts come right off after heating them cherry red.  For future ref.   Long in the future, I hope.

I still want to know what the pressure should be.  Regardless of the end play, you, or anyone, should be able to verify that the turbo is putting out the proper pressure at a given rpm.  I have seen posts where one BN said he had 27 pounds and another said he never saw more than 22.  Obviously they have boost gauges.  I should think a boost gauge would be a required instrament so you could see the pressure falling off and know why you are smoking and dropping a gear on that certain hill and your MPGis in the toilet.

Hope Dallas gets home soon.

Thank you,

John

Boost is a relative assessment, lot's of variables make up the amount of boost you will see.
What is the A/R of the turbo?
What injectors?
How is it timed?
If it's a DDEC, how is the ECM set up? and what are the running parameters?
Was the reading taken on a slight upgrade? a steep upgrade? on the flats? Heavy load? light load?
What pistons? What compression ratio? Is it just a smoke turbo? trunk pistons? crossheads? What liners were used in the last rebuild? What size are the exhaust ports?
Is the gauge accurate?
At what ambient temp were the readings taken?
What size in and out on the muffler?
Is it a turbo rated muffler?

Lot's of questions and not really any easy answers.

Good Luck!
Sorry I couldn't be of more help.
Dallas
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« Reply #22 on: September 04, 2007, 06:37:55 PM »

Brian, you have a sort of boost gauge.   Your DDEC monitors the boost pressure.  It'll set a code if the boost drops.
I couldn't tell you whether to replace your turbo, but my turbo has a good bit of wear and the turbine will move slightly. 
Been that way for years.  No appreciable change. 
The intercooler would be the target of most of the turbo should it frag.  No good outcome from that. 
I'd get someone to set a known good, or rebuilt turbo on the counter so that you can compare the feel of the turbine. Most used turbos with no oil pressue will have some free play.   The hard part is deciding what's normal when feeling it by hand.  It should turn smoothly...no feel at all.  If you feel roughness when spinning it by hand, it's failing. 
If the turbo wears out, it'll leak oil, smoke, and once the boost drops from a predetermined pressure the DDEC unit will shut you down.   A CEL will set and you'll be able to download a code indicating "low boost pressure".
Then you buy a turbo...maybe. 
Before I bought a turbo, I'd be doing some comparison 'feeling. 
The local truck shop oughta have some intakes open allowing you to see what a normal used turbo feels like. 
The key to keeping a turbo healthy is to allow it to cool down for a few minutes after the engine has been operated under a load. 
To do otherwise will coke up the bearings and seals as the turbo winds down without oil supply and heat cooks whatever tiny bit of oil was in the bearings and seals.  It won't spin long when you spin it by hand, but it will spin for a several seconds after shutdown. 
You can hear the turbo spooling down when you shut the engine off.
And, if you are familiar with turbos, they make a "death rattle" when worn out... they don't smoothly spool down, they buzz and vibrate.  That is a dying turbo when you hear that.  You'll have to stand at the engine and shut it down from the engine room to hear the noise.   
If memory serves me, didn't you lose a turbo line...or maybe it was leaking?  I remember your oil filter adaptor got new "O" rings?
Good luck, JR


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belfert
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« Reply #23 on: September 04, 2007, 07:11:25 PM »

If memory serves me, didn't you lose a turbo line...or maybe it was leaking?  I remember your oil filter adaptor got new "O" rings?

The initial thought was the oil filter adapter was leaking.  The real culprit was the oil feed line to the turbo.  The oil feed line had a hole worn in it because the clamp holding the line to the engine had broken and the jagged edge cut the line.  BK fixed the line with some couplers and a piece of brake line.

I still have the seals and gaskets for the oil cooler and oil filter adapter.  I'm thinking about replacing the seals in the oil cooler while the coolant is still out.
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« Reply #24 on: September 04, 2007, 07:55:18 PM »

May want to remove that patched turbo line and get a one-piece line and install.  Turbo don't need all the weight and stuff on the line.  That line will may develop harmonics due to the additional weight and crack again. 
Let me know how the turbo exams go. 
If that oil filter adaptor isn't causing any oil leakage, I'd leave that alone.  They are not know to cause problems. 
Best, JR
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JR Lynch , Charlotte, NC
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« Reply #25 on: September 04, 2007, 08:03:25 PM »

For my boost gauge, I ran 1/4 inch tubing from the emergency shut down housing, (just upstream from the blower), all the way to the dash (40ft), to a $5 air pressure gauge. Works very well, with no delay. When there is no leak in the line, it should be accurate. Regardless, you get used to what it reads normally, and any variation indicates a malfunction. Works for me.
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JC
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belfert
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« Reply #26 on: September 04, 2007, 08:08:11 PM »

If that oil filter adaptor isn't causing any oil leakage, I'd leave that alone.  They are not know to cause problems. 

The oil cooler is what I would replace the seals on, not the oil filter adapter.  The oil cooler is a known leak issue on a Series 60.  I'm kinda thinking that maybe I should just wait, but I dread dumping the coolant again.
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belfert
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« Reply #27 on: September 04, 2007, 08:10:45 PM »

For my boost gauge, I ran 1/4 inch tubing from the emergency shut down housing, (just upstream from the blower), all the way to the dash (40ft), to a $5 air pressure gauge. Works very well, with no delay. When there is no leak in the line, it should be accurate. Regardless, you get used to what it reads normally, and any variation indicates a malfunction. Works for me.

My Series 60 has no blower so I can't measure from there.  I haven't looked yet to see if there is any sort of boost line coming off the turbo that could be used to measure boost
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« Reply #28 on: September 04, 2007, 08:25:37 PM »

Quote from: NJT5047
May want to remove that patched turbo line and get a one-piece line and install.  Turbo don't need all the weight and stuff on the line.  That line will may develop harmonics due to the additional weight and crack again.  
Let me know how the turbo exams go. 
If that oil filter adaptor isn't causing any oil leakage, I'd leave that alone.  They are not know to cause problems. 
Best, JR                                           

JR you are 100% correct that it could crack again! And I have seen them do it, but I have also done the exact same repair as I did on Brian's before. On one in particular, I know it lasted the next 5 yrs I know of, and was still like that when it was sold! And some others I did for others that I have no clue as to how they held up. So by no means am I saying it couldn't or wouldn't break again!

And Brian to tell you the truth JR has a very valid point, and yes if it were me and you had things that were in our way the last time out of the way now I'd go ahead and fix it! But if it's still as difficult to get to as before, I'd do like I told you when we fixed it ! Just remember to make it a part of your pre/post trip check out procedure! (no I didn't call it a pre-trip inspection as it's not a commercial vehicle/driver, but Brian and I did discuss things that should be looked over before & after every trip!) FWIW Grin  BK  Grin
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belfert
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« Reply #29 on: September 04, 2007, 08:50:55 PM »

When I was at BK's place I couldn't find anyone who had the one piece line in stock that could get it to us overnight at a reasonable price or was within driving distance.  I don't believe any place that was close enough for one day UPS ground had one.  I didn't want to pay as much in air freight as the part would cost.  In the end, BK said he couldn't replace the line with the one piece one without removing a bunch of stuff anyhow.

It would be very difficult to inspect this line before every trip as it is pretty buried.  I'm not sure spending the $40 for a new line would be worth it even though it is easily accessible at the moment.
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« Reply #30 on: September 05, 2007, 12:08:52 PM »

Dallas,

My apologies.  I had no idea it was that complicated.  Thank you for taking the time.  Sorry if I put you on the spot.

Lost,

That is exactly the procedure I was refering to.  Find out what it is now doing and compare future readings.  The remote sensor for air pressure is far more spendy that the trierd and true air line to a conventional gauge mounted at the driver.  I am really interested in the boost you are getting from what engine and how it is equiped.  I feel certain you can't reference all the info that Dallas mentioned in determining min performance readings for boost pressure, but I think you could reference the salient ones.  1,800 rpm, full throttle at load, muffler spec, after cooler, altitude at test.  What is your "norm" reading"?  I found your comment that there is no apparent lag for a pressure reading really good news as that was the only consideration I had for installing a line to the engine bay.  Thank you very much for the "good news" on our ability to collect and use this information.

Sincerely,

John
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« Reply #31 on: September 05, 2007, 06:02:42 PM »

All I did was install the Airesearch (Garrett) specified for my engine in the service manual (4-71 DD). Put in the newer oil seals in the blower and a bigger exhaust (5"). Same injectors (N65's). I even kept the old oil bath air filter which works quite well. I haven't done a air to air intercooler yet, but thinking about it. I get 7 to 8 psi of boost at full load. I was expecting more like 15 psi, but it has made a very noticeable difference in power anyhow. I now go up hills one gear higher than before so I'm happy. My engine is set at 2375rpm no load, with advanced timing (it should be set to normal timing for turbo) but you'd have to have the engine out of frame to get at the timing gears. Bigger injectors would be possible, but that would involve a bigger rad for cooling, and lousy fuel mileage.
Just see how much boost you get at full load on the governor, so you know. Then if one day you don't get that, you'll know a charge air hose came loose or something else packed it in. Keep it simple in you mind. Don't sweat the details too much, just drive it.
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« Reply #32 on: September 05, 2007, 09:25:39 PM »

Lost,

Thank you thank you.  That is exactly what I would want to hear and you kept it simple.  8 psi at full load for a stock 4-71.  That plugs that hole.  I couldn't agree more that knowing what it did is a great troubleshooting tool.  I think that historic data would come in handy if you replaced your turbo and the new one only did 4 psi.

Thanks again,

John
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"An uneducated vote is a treasonous act more damaging than any treachery of the battlefield.
The price of apathy towards public affairs is to be ruled by evil men." Plato
“We can easily forgive a child who is afraid of the dark; the real tragedy of life is when men are afraid of the light.”
—Pla
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