Hmmmmm, there went the....

[bmoeller]

..... TURBO.



We have a C-12 Cat in the one semi trucks. The turbo grenaded on me pulling up a small hill (loaded with corn). Found half of the compressor wheel. Who knows where the rest went to. The piece I found was sitting on the oil cooler.



Looks like the wheel snapped in half (wasn't a completely fresh, clean break), causing the shaft to snap off, then it broke the compressor housing off the turbo, just a half inch or so, past the V-band clamp. :--) At first, I thought I blew a intercooler boot off, but I wasn't that lucky.



Got the intercooler flushed out and the new turbo installed, and the truck home.

 

[Rescue Ram]

Bummer... I don't suppose it is one of those new ACERT engines?

 

[bmoeller]

No. It's a '99.

 

[Rescue Ram]

Ahh, ok. I don't suppose you have any experience with the ACERT engines, do you? I am interested in how they're holding up...

 

[MMiller]

Bryan, you just sent me some sweet pics of that truck too! Should have held out for the C16 What do you think failed first? I have had some c12 turbos fail, but mainly the shaft gets a bunch of endplay and starts hitting the housings.



Oh yeah, don't tell RR you know me! :-laf

 

[Grey Wolf]

My boys find a lot of (turbine) wheels in the first bend of the exhaust pipe... ... .

 

[bmoeller]

What do you think failed first?

Howdy Mike.



A C-15 or 16 would be sweet. The 12 is still a nice step up from an E-7 350. The T-8 is A LOT nicer truck than a CH Mack, too.



From looking at the compressor wheel, it looks to have snapped in half first. The bearings felt good (no perceiveable play at all), and it spun by hand nicely. Felt like new. The wheel snapped right in half. Straight across the center-line. Only part of the break was fresh. The rest of the break was a bit dirty looking. It was working on it for a while. This turbo was original and had ~363k on it.



I wish I had had my camera. Never seen anything like it before. I've seen the bearings on the hot-side fail before, and a shaft snap on another. Both were on the same truck (Mack). Boss's brother almost always shuts down hot. Glad he doesn't drive the trucks much anymore. Got tired of chewing him out on doing that. I caught the second one before it let go. Oil was seeping out from behind the V-clamp to the down-pipe, on that one. That replacement only lasted 50k. Latest one has maybe 150k on it so far.

 

[bmoeller]

My boys find a lot of (turbine) wheels in the first bend of the exhaust pipe... ... .

Sounds like somebody needs to learn to let the turbo cool off at shutdown.

 

[MKoth]

Ahh, ok. I don't suppose you have any experience with the ACERT engines, do you? I am interested in how they're holding up...

At the old shop I worked at in Storm Lake, we had a local guy with a 2004 379 with the C15 ACERT motor. He had several instances where the bolts holding the turbo assmebly to the manifold would break, and blow out the gasket.



When I worked foir Ziegler Cat, we had a lot of blowby issues with the new ACERT motors, mostly cause the oil spraying on to the rocker arms would shoot straight into the vents on the top of the valve covers.

 

[MMiller]

MKoth, when did you work for the big Z? I did my tour of duty from aug of 97, to january of 01. I worked in the main heavy equipment shop.



The Acert c 15's I have seen have had some turbo issues. I am a little concerned that the secondary turbo runs hot enough the Cat yellow paint is burnt on the COMPRESSOR housing. Have not seen very may in the shop in Davenport yet. Course I haven't worked in the shop for over a year now. My truck has an c7 acert in it. After the injectors were changed it has been running right now. Has good power for 230 hp/660 ft lbs.



Michael

 

[MKoth]

MKoth, when did you work for the big Z? I did my tour of duty from aug of 97, to january of 01. I worked in the main heavy equipment shop.







Michael

Started in December 2003, two weeks out of tech school. Was "let go" March of 2004. Was told that I didn't have enough experience to keep pace with the other mechanics that had 5+ years of experience.



Got a job with a truck shop out of Storm Lake that was 85% Peterbuilt with Cat traffic, made more money, and learned a heck of a lot more.



Now I am in Des Moines running my own little shop doing meduim and light duty diesel repair, as well as a little performance stuff every now and then.





Matt

 

[MMiller]

Wow, I used to go to school with a guy from up by Storm Lake, Laurens was the name of the town. Spent some time up in that part of the state too. Well, I really don't miss working for the Big "Z" any. I hope your business turns out ok. Would be quite funny to have a prosperous business in the same town as a company that didn't think you capable!



Bryan, you think the wheel was cracked and then kept working on itself until it failed? Did you end up finding ALL the parts? I have had techs tell me to find all the parts, cause if they are in lines they will get back to the new turbo. But it sounds like the whole thing ruptured and ventilated itself.



I did end up with a turbo from a 4 cylinder perkins from work the other day. Probably would not worked well on the c12 though. :-laf :-laf



Michael

 

[Pmaloney]

As far as Cat turbos go I have not been impressed. Cat has always had a good name in my book, If I could of found a Cat cheap to put in my truck I would have, but the flip side to that is that the school district I work for has had nothing but problems with the new C7's turbos, I have towed quite a few back myself with shelled turbos and were talking 20-40,000 miles. Not a good thing. Some of that could have something to do with cool down times, or a lack thereof, but our Cummins and IH DT-466's dont have anywhere near the problems the Cat turbos do ???

 

[CPjMech]

C-12's have chronic turbo failures. The comp wheel will split in half, there is an after failure service letter out on some of them along with a redesigned turbo.

 

[MMiller]

Well my c7 has 28,000 miles on it and probably about 1200 hrs. Original turbo so far. I'll hope for the best. I have only replaced a couple c12 turbos, but all my c 12's are in ag and heavy equipment. I don't work on truck engines.



Michael

 

[bmoeller]

Bryan, you think the wheel was cracked and then kept working on itself until it failed?

That is what it looked like to me. From the way the bearings felt, I think it could've gone another 360k, easy, if the wheel hadn't failed. Still felt like new.

Did you end up finding ALL the parts? I have had techs tell me to find all the parts, cause if they are in lines they will get back to the new turbo. But it sounds like the whole thing ruptured and ventilated itself.

Didn't get them all. Since the housing broke, they could've gone anywhere, since I was moving at the time. We did get the CAC flushed out. There where a few pieces in there. I did find some in the piping, too. Small pieces were also stuck in the first rubber elbow that is attached to the compressor housing. The biggest piece of the wheel was sitting on the oil cooler.

C-12's have chronic turbo failures. The comp wheel will split in half, there is an after failure service letter out on some of them along with a redesigned turbo.

That's interesting. I wonder if it could have been replaced on their (Cat) dime. We did get a partial core credit for it, at QC Kenworth. Could I get a copy of the service letter?

 

[bmoeller]

May have a theory.....

maybe.



What is the boost level on a 335hp C-12 and a 430hp C-12? Do they use the same turbo, with different wastegate settings? The new turbo I put on, the w/g is set at 22. 5psi. The decal on the timing case cover looks to say 335hp, for this truck. Not 100% sure, but I beleive somebody upped it to the 430hp setting.



Ran the truck with a load today. The new turbo puts out 22. 5PSI, as mentioned before, but I was seeing a max of 32psi on the old one that blew on me. We didn't buy this truck new and is our first Cat powered truck. So I don't know what is "normal", boost-wise. The wastegate was rusty on the old turbo, so it could've been stuck, causing the turbo to overspeed/boost, causing the wheel to let go.



Can somebody shed any light on this for me?



I did notice, with the lower boost, the truck didn't feel as strong as before, as per the Butt-o-meter. The bullrack was pulling really hard today, with the wind, so I could be all wet on this part.

 

[MMiller]

When you got the turbo, did the parts guy ask for engine serial ##/arrangment number? In theory the arrangment # should have been changed if the engine had been rerated and differnt parts were needed. Give me a serial # and I can look up part numbers Bryan.

Michael

 

[bmoeller]

I wasn't the one to go after the parts. My boss did. I worked on the tractor in somebody's driveway. He had the truck S/N, but I don't think he had the ESN, unless their computer showed it. Can't say. He did take the old turbo with him, though, FWIW.



I don't have the ESN with me. I'll have to get it for you tomorrow.

 

[CRHardie]

Looks at the way the turbo is assembled. The compressor wheel is threaded onto the shaft, and when torqed it is stressed That is why they split If they were held on by a nut like a Holset they would not fail as often. I had a c12 turbo fail and replaced it with a Cat reman and 50 miles later was taking the muffler off to retrieve the exhaust wheel again The compressor wheel was in 2 pieces again. Craig