Turbo Leak 12V71

[Briankinley2004]

On the maiden voyage back in April I ran on cruise for about 200 miles. When we got to the destination nothing appeared out of ordinary in the engine room. A week or two later I happened to notice a spot of soot on the aft side of the exhaust blanket on the far starboard turbo. I hadn't run the engine since the voyage so I removed the blanket to find the clamp broken that connects the exhaust riser to turbo(first picture)




I have put about 110 hours on the engines since and have been keeping an eye on this or so I thought. Haven't ran the boat other than cranking engines at dock since October. I decided to do some painting on the engine and crawled behind the engine to find soot on the forward side of the new blanket. Another place about the size of my fist. I removed the blanket and it appears the soot is coming somewhere between the two clamps and an area where some lines (oil?) connect. I am unable to find any diagrams of how the turbo is assembled or sealed but both clamps appear to be intact. Any suggestions on what to check first? I will also state that the clamps that hold the air silencer to the turbo intake where loose, probably because I forgot to tighten them when I removed it to clean after the first incident.




I also inserted my boroscope into a plug in the top of the air shut down flaps serving this turbo. I will post pics in the reply as it wont let me put but 3 per post.

 

[Briankinley2004]

These are pics of the turbo and boroscope. Not sure if I need to remove the flaps and inspect the intercoolers or if the amount is not enough to warrant this. Any comments either way are appreciated.




Not sure what the rod is for in this last picture but thats about as far as I could get the boroscope into the hole where the plug was removed.

 

[racclarkson@gmail.com]

Before tightening the clamp, you have to pull the turbo and exhaust pipe together. To facilitate this, loosen the airsep mounting bracket from the manifold. With that much soot, you may have to pull the turbo and clean the joint to get a good seat. Some folks apply hi-temp sealant. I haven't found the need, myself.

 

[Briankinley2004]

I dont have airseps but I have the air silencer assembly off right now. Is there any type gasket in the middle portion where it leaks or is all that metal to metal too?

 

[racclarkson@gmail.com]

I dont have airseps but I have the air silencer assembly off right now. Is there any type gasket in the middle portion where it leaks or is all that metal to metal too?

No gasket.

 

[oceanjake]

If you are leaking oil from that v-band clamp your turbos likely need a rebuild. You are getting oil in the exhaust side of the turbo. You should look into this.When that is done, there are a couple things you can do to get the mating surfaces under the clamp to seal. 1). Loosen up the four bolts holding the base of the turbo to the exhaust manifold before tightening the v-band. Then retighten at the end. 2) there is a compound made for this called silkolene 762 jointing compound. It is pricy! Be advised that even after dry it is water/liquid soluble.

 

[racclarkson@gmail.com]

I think I’d try to bring the exhaust pipe to the turbo rather than break that manifold joint. There is some flex in the pipe. You can loosen the pipe’s support arm if need be.

 

[oceanjake]

I fought breaking the base from the manifold as long as I could, but eventually caved and it worked. The fact is there is a ribbed metal gasket on the base but no gasket on the slip fit flange. The gasket is $4 and easy to slide in if needed. It’s an option. I’m still trying to figure out why that silkolene is so expensive. I think it msrp’s at $200 a tube.

 

[SKYCHENEY]

I don't like the Silkolene. I use Cat High Temp Manifold sealant. It works better and is much cheaper.

 

[Briankinley2004]

If you are leaking oil from that v-band clamp your turbos likely need a rebuild. You are getting oil in the exhaust side of the turbo. You should look into this.When that is done, there are a couple things you can do to get the mating surfaces under the clamp to seal. 1). Loosen up the four bolts holding the base of the turbo to the exhaust manifold before tightening the v-band. Then retighten at the end. 2) there is a compound made for this called silkolene 762 jointing compound. It is pricy! Be advised that even after dry it is water/liquid soluble.

Not leaking oil. It is blowing soot out. Everything is dry, no oil, just soot. The picture that looks oily is inside the shut down damper. I put a boroscope through a plug in top of the damper assembly. Those 4 bolts on the manifold look like they are pretty rusty. I figure they will break but will try soaking them in crow oil first.

 

[racclarkson@gmail.com]

Not leaking oil. It is blowing soot out. Everything is dry, no oil, just soot. The picture that looks oily is inside the shut down damper. I put a boroscope through a plug in top of the damper assembly. Those 4 bolts on the manifold look like they are pretty rusty. I figure they will break but will try soaking them in crow oil first.

It’s ok, they aren’t threaded into the flanges. They will be brittle as hell from all the heating and cooling and likely to break when you reinstall. Go ahead and get some new grade 8’s. Even if you use a new gasket, add a light smear of exhaust sealant. I’ve never had issues with the permatex.

 

[kingsley_oasis]

My leak was caused by a cracked support for collector, and a loose bracket on cylinder head. PO had resealed couple of times, so luckily I inherited a tube of the high price liquid gold Silkelene sealer.
All good now for three years. Had to loosen everything, align seal and tighten. I had no issues with replacing gaskets and flange fasteners. Note screws that fix bracket to cylinder head need to be sealed, or they will leak oil.
Oh and collector is its heavy.

 

[Briankinley2004]

It’s ok, they aren’t threaded into the flanges. They will be brittle as hell from all the heating and cooling and likely to break when you reinstall. Go ahead and get some new grade 8’s. Even if you use a new gasket, add a light smear of exhaust sealant. I’ve never had issues with the permatex.

Robert thanks for info on bolt grade. I was wondering if it was ok to use grade 8 or it it had to be some special heat resistant metal like the high dollar sealer. Ray I hope I dont have to go that far with mine. The collector has been "re-did" in stainless steel so not sure if it would be lighter or not. Its not cast so hopefully so.

 

[bigbill]

if you need sealer go to an auto parts store. i bought a tube of permatex exhaust sealer. it resists heat up to 2000 degrees. i tried to get some from the local cat dealer and he said it would be about 2 weeks to get,he said why dont you try and auto parts place for a sealer, he said the cat stuff is good to 2000 degrees, look for something in that range. i did and the tube cost me 7.65 cents. i ran her for a while at the dock and no leaks, wont be running her up to speed until summer

 

[SKYCHENEY]

The Cat stuff is made by 3M. They make good stuff. I'm not saying that the auto parts store stuff won't work, I'm just saying that we have used the Cat product for years on construction equipment and it works well so that is what I used on the boat.. YMMV.

 

[racclarkson@gmail.com]

Yep, I've used the CAT stuff for years along the way, but on CATs. It may not be against the law, but using CAT sealant on Detroits (a/k/a known leakers) is just tempting the gods and, generally speaking, in poor taste. But what the hell, I'm using toilet bowl cleaner on my hull.

 

[rustybucket]

I just went through this SAME exact issue with our starboard engine. Both turbos were leaking at the flange and one turbo was leaking oil into exhaust.

I pulled both turbos off, rebuilt one of them (wasn't bad at all, pretty simple pieces if you have the manual).

On install I thoroughly cleaned and filed both mating surfaces and used a high temp jointing compound I bought at the url below (no affiliation)

https://dieselpro.com/detroit-diese...rature-jointing-compound-type-for-turbos.html

Seems to have worked great, no signs of leaks at all.

On a side note, for getting soot off (mine was worse than yours before we caught it) I used turbo sootmaster (I got a gal of it) on advice of an old diesel mechanic.

https://realcleanproducts.com/products/turbine-soot-master?variant=12548333764663

It works great, I use it to clean the transom now (I keep some in a spray bottle with the boat cleaning stuff)

I would HIGHLY suggest replacing all the nuts on the vband clamps as well, from my understanding they are a 1 time use item. I tried to reuse them and both stripped out before I got to the rated torque setting. So I had to clean and re-do everything (major pita). The new nuts were less than a dollar each. Torque to book specs (torque, loosen, re-torque)

 

[Briankinley2004]

Thanks for info Rusty. Any info on what the torque should be on the nuts. I didnt use a torque wrench on the first clamp I replaced as I was unaware of this. Someone told me to tighten it then tap with hammer and tighten again. I probably need to re-do all the clamps

 

[bigbill]

i was told the clamps should be replaced. the heating and cooling cycles it goes through weakens them

 

[Briankinley2004]

I have some extra of the acorn clamps that do the exhaust to the turbo. It looks like the ones where the leak are may be a little larger in diameter than the other one. I plan to disassemble next time I am down there. I ordered some of the soot cleaner but am holding off on the liquid gold until I see if it will seal without it. Still trying to find out if I need to clean the intercooler. Looks like I would have to remove the flange with the 4 bolts to get access to inspect it with boroscope. I read on an old boat diesel post that if the engines arent smoking black most likely you dont need to bother cleaning inter coolers. Then another place I read they should be cleaned to remove soot.