6CTA Aftercooler Removal and Service Issues

[Gerasimos]

After the thorough information and write-ups from Tony and the SBMar team, and the readily available parts kits they supply, I decided to tackle my aftercoolers this year. This is my second year with this vessel, a 2001 Tiara 3800 Open with 6CTA’s, roughly 500 hours. It was previously serviced by Gorham Diesel out of the Boston area. The aftercoolers were replaced with brand new ones 4 years ago, so I am assuming that this is the first “service” being done on them since.  A bit of a background on what led me to looking into them: Towards the end of last season the port side engine would creep up to 170 degrees certain times. I did the Barnacle Buster flush on both engines, tons of crud came out, but it didn’t fix it. It would consistently be between 165-170 degrees on the port, and always 160 on the dot on the starboard. Figured that the aftercoolers may be part of the issue and it can’t hurt to service them at this point. So I purchased SBmars kit and got to work yesterday The starboard side came off easily after a bit of Kroil overnight. Pictures of what I am looking at below, including the core which is currently sitting in a bucket of Barnacle Buster for a couple hours. Everything seems to be OK. I had a bit of the green corrosion in the caps, and I sanded that down and sprayed a bit of paint on it.  The port side one, on the other hand, has been a total PIA. It’s been soaking in Kroil/WD-40 since last night, from the top, bottom and side inlets . The absolute best I’ve been able to get it out is a couple of inches. It will not budget. You can see the last 2 pictures of what I am currently looking at with the core “stuck”.  UPDATE: Was able to remove it. Here are some side by sides of the “good” core vs the problem core. The metal tubes are flattened on one side. The inside of the housing is filthy. I need to clean it up because its got alot of build up that doesn’t seem to be corrosion. Is there any way of rescuing this with a good cleaning and service? Even if I can buy a year or two out of it especially since these are only 4-5 years old.

Topic

[Gerasimos]

That starboard core looks like crap but maybe try pressure testing it after cleaning it incase it still holds pressure?   I dont have the SMX housing (does one exist?), but I do have the SMX core on my Port Side with the original housing and no issues, pressure test passed. My 2nd year with it btw, previous owner didnt do the bench and when I went to do the bench I found corrosion and a failed pressure test 

[clintons]

Hi Gerasimos – I did see the cooler housing on their bench and the core out. Looking at ordering the replacement SMX unit from sbmar – are there any known issues with these? Is anyone running them that can advise? 

Am I right in assuming that an existing core won’t fit inside the SMX housing or is that incorrect?

Any help is appreciated – not an engine guy and this is looking expensive.

Thanks

 

[clintons]

HI Steve – ours is a 2005 as well. 

Below are photos of the AC units (left is starboard) and also the cores. Port core is fine. 

When they pulled the unit apart, a lot of red sealant / hardened material flaked away from the end cap joins. 

Not looking too healthy at this point (I am talking about me)

[Gerasimos]

I don’t want to pull the trigger of blame, but 17k for a service 2 years ago and this aftercooler has cracked since? Unless something is catastrophically wrong, 2 years is not that long of an interval to do the bench service on the Aftercoolers. Is it possible they didn’t actually do anything to your coolers but said they did?

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clintons

[Steve Lewis]

Clintons,

Welcome to the 460DA owners club.  We have a 2005 model year with 480CE’s.  What model year is yours?That aftercooler pic does not look good at all AND that is the tough one.  The starboard side.  Are you in Salt Water?  Did your mechanic remove the entire exhaust system on the strbd side, wet elbow and back so that both sides of the turbo have been looked at AND the wet elbow has been assessed?   

Do you have pics of the port side?  Post some other pics of the whole engine complex.

 

1 user thanked author for this post.

clintons

[clintons]

Aftercooler Issues – not pretty

Hey. Borught my 460DA in Jan 2022. Had engines fully serviced in Sept 2022. AfterCoolers were pulled cleaned and pressure tested then re-fitted. Have since found out the Co. was a bit on the dodgy side. $17K for 2 x engines / gen and aftercooler service. Have recently had turbo power loss in starboard engine. Current mechanic found serious crack in the bottom side of the cooler. They have removed and it seems the core is corroded to the housing. not even press can get it out. When mechanic removed the cooler they notice there were no bolts attached to the bottom of it holding it to the brackets (Port is the same apparantly). Also wastegate in turbo on that side was seized. Other than that the turbo was in good condition.

At a guess, how bad is this looking?

[Douglas Fairchild]

Aftercooler inventory

I went to my local Cummins dealer last week and he found one In Memphis TN.  I think they had three housings in stock. Shipped overnight had it the next morning.  

[Gerasimos]

Update #2

So the problem aftercooler core failed the pressure test. Huge leaks in one of the tubes that is cracked open near the bottom of the assembly. Assuming these are not repairable by a machine shop, looking to order a replacement. 

 

As for then housing, really hoping that it’s salvageable because I don’t believe any are in stock anywhere in the country right now. The SMX aftercooler seems to be shaved down .030″ to accommodate a light shaving/sanding of the top/bottom of the housing where the caps sit to make the seal, so I’m cautiously optimistic that I can get a seal on the housing with a new core.

 

Yes, single, LOL.

[MATTHEW]

Also, you are either single or have a very understanding wife to be doing that in your front hallway!!

[MATTHEW]

Much more important than the ID is the seal surface and that really doesn’t look too good either.  Clean that up good and polish it by wet block sanding it w/600 grit and look for pitting.  When it’s dirty like it is in your picture it sometimes looks worse than it really is.

I have found the stiff scotch-brite paint stipper discs that fit in a drill to be effective at cleaning up the ID of the housing so the cores slide in & out easily–and then make sure you liberally apply a good metal lubricant.

4-5 years in salwater is more than enough to cause problems.  I do them every 2 years and that way they just slide apart–it’s a non-issue to service them, and as you remove & replace the aftercoolers you spend some time looking over the rest of the motors to stay ahead of anything like leaks, loose hose clamps, etc.  Much better to do too early than too late and I’d much rather have a 20 year old set that has been properly maintained than a relatively new set that hasn’t been touched in 5 years of saltwater use.  Again, really not trying to beat you up, just sharing what I’ve learned.

[Rob Schepis]

Use a rubber sheet, neoprene works great.  Yes, it’s the ends of the housing where the o-rings seal that is critical.

[Gerasimos]

I agree, I should have done this sooner, but being that the previous owner installed them brand new about 4-5 years ago I figured that they would not be totally FUBARd at this point.   I am trying to pressure test the damaged core but can’t get a good seal on the bottom/top using a foam pad. Anyone have any recommendations to replace the white sheet in these images with to get a better seal?

 

Also, the housing for the port side (problem side) doesn’t look to great inside. I can’t get the core to slide back in since its corroded inside the housing towards the middle. Is my understanding correct that I can sand that down as long as there isn’t bad corrosion on the ends where the cap makes the seal?

[MATTHEW]

Barnacle buster flush might be OK for in-between cleaning descaling, but it does not replace the need for on the bench breakdown & cleaning of the aftercoolers and heat-x’s.  

I would start by trying to unfold the smashed tube ends.  some of those tubes are significantly blocked.  After you have that fixed then pressure test them w/your fingers crossed.  Not trying to beat you up but this should be done in November (or whenever you pull the boat out for the season) in case there is a leak as then you have the whole winter to find someone to try to repair it.

[Gerasimos]

Thanks for the quick reply guys. The engines smoke a little bit just on start up, but I wouldn’t say anymore more than normal, and both about the same. 

 

The flattened ends are on the bottom, correct.  I currently have it sitting in a bucket with diluted Phosphoric Acid to see how clean itll get, and I will clean the inside of the housing with a brush and some simple green to see how we end up. I don’t mind trying to figure out the pressure testing thing, or worst case taking it to someone, if we think it’s not totally FUBAR’d.

Both engines theoretically had all the same maintenance done before me. Bizzare that they are in such differing conditions. This port side engine has been running 5-10 degrees warmer and a Barnacle Buster flush didn’t fix it last season. Thats what led me to doing this before this season.

[Neto]

after you clean them you should pressure test them to ensure they dont leak, if they do then it could be a challenge to repair, if its just one hole maybe plug it somehow??? Looks like half of the aftercooler was submerged in saltwater.

Does the engine smoke a lot on startup?

[Rob Schepis]

The flattened tube ends are the bottom of the core, right?  At some point in this core’s life there was a zinc that came undone from the brass cap and bounced around in there like sneakers in a dryer.  Not sure if this happened in your 2 years of ownership or sometime with prior owner.  I’d start by pressure testing that core.  Plenty on the forum here for searching about building your own core tester.

[Author]

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