CAT 3126 engine turbo boost/RPM issue. New owner, help!

Discussion in 'Sport Yachts/Yachts' started by Wistlindixie, Jun 22, 2018.

  1. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    History:

    I am a new owner of a 1996 Sea Ray 450 Sundancer with CAT 3126 engines this year. I purchased the boat with no service history. Previous owner no longer available, his wife sold boat and has no details. Engines had fresh white paint new belts, hoses, filters and air cleaners with not even an oil stain anywhere. Survey with sea trail went OK. CAT looked at engines after and said they looked fine, only found loose belt. They did oil and filter changes. Boat had previous salt water use.

    Issues:

    During sea trial, the port engine ran @ 2700 RPM and STBD @ 2800 RPM @ WOT for testing. No real issues.

    On first 4-hour trip the boat was running with SYNC on at about 2200 RPM and @ 30 min in it seemed like the engines stalled. Shut everything down and checked everything but seemed fine. Went another 30 min worked fine until it happened again. This occurred 3 times over the 4-hour trip. Boat sat idle a week and on 2nd use of 30-min to an hour we had no boost and low RPM on port engine. Return to slip found considerable amount of oil under port engine. It was going out the top of the Turbo into cooler.

    Questions:

    1. I hear these engines have “issues” with heat exchangers and coolers, especially with salt-water use. What are the “issues” and how are they corrected?

    a. Does the salt ruin these or do I just need to flush them with Rydlyme?

    2. I have almost got the turbo removed, it is only held on by the four flange bolts on the exhaust side of the turbo to the engine. I cannot seem to get to those to remove them. Special tool? Advice? I am already twisted in a pretzel trying to get to that side with the cable Glendening and exhaust in the way.

    3. Do I need to completely remove the cooler in order to remove the oil after the turbo blew oil out the top? Or can it be cleaned / drained while installed? I really do not think I can get it out of port side space.

    PICTURES:
    I know pictures help. Here is image(s) of the turbo and the oil it spit out.

    {not sure why the system rotates the pictures after upload, sorry.}

    IMG_1911.jpg

    IMG_1910.jpg

    IMG_1906.jpg


    Turbo fan seems solid, no wobble or play side to side. Will just a seal leaking oil cause symptoms?
     
    Last edited: Jun 22, 2018
  2. The Bill Collector

    The Bill Collector Well-Known Member SILVER Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    I have the same engine, but can't comment.... Frank W. is your go to CAT man !!!
     
  3. swaterhouse

    swaterhouse Active Member GOLD Sponsor

    328
    Jan 7, 2015
    Mattapoisett, MA
    2007 Sundancer 44
    Cummins QSC 8.3
    Please tell me you didn't really run Wide Open Throttle all the time? I know next to nothing about the CATS, but I assume they are rated the same way Cummins are, and they are NOT supposed to run WOT 100% of the time they are rated for maybe 20% WOT, and most people (myself included) run less than 1% at WOT and that is spread over multiple days.

    Good luck, but sounds like you have some real issue there.
     
    The Bill Collector likes this.
  4. Graham Lorimer

    Graham Lorimer Member

    393
    Feb 13, 2009
    Boat in Sant Carles, Spain. I live in Cheltenham,
    Sundancer 460 2002
    Volvo 480 HP
    Raymarine Electronics
    Avon 320DL RIB
    Yamaha 25HP 4 Stroke
    Volvo 74 TAMD EDC
    I agree entirely with swaterhouse, why would you ever run at WOT for any time, there is a lot going on back there at those RPM and there is just no point in stressing them, ever!

    If you need to go faster then the rated cruise rpm, buy a different boat.

    Graham
     
  5. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    SEA trial!!!
    NO! Trip was about 2200 RPM
     
  6. The Bill Collector

    The Bill Collector Well-Known Member SILVER Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    Cruise for us is the 2200-2400 range... sweet spot.
     
  7. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    Feeling a little beat up after those post. Not sure anything helpful was contributed.
     
  8. Boater420

    Boater420 Well-Known Member

    Mar 11, 2015
    Clearwater, FL
    '97 330 Sundancer
    V-Drives
    Westerbeke 4.5BCG
    Twin Merc 454's
    I read it the same way, might want to re-write that so others follow the post properly. I don't think anyone was trying to beat you up.
     
    Steve S and The Bill Collector like this.
  9. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    Okay, I see that. Will edit....
    My fault.
     
  10. The Bill Collector

    The Bill Collector Well-Known Member SILVER Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
    Like I mentioned earlier reach out to Frank Webster he has 20+ years with his 450 & the CATs in it... All in salt.

    "a. Does the salt ruin these or do I just need to flush them with Rydlyme?"

    Our boat has been in salt for the past 19 years, 11 years under my ownership. I have done rydlyme 2x great results.

    Sorry, I can't be of more help...
     
  11. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    - Bill collector. apologize, I was not saying you were unhelpful. AND I did have a typo (thanks boater420) in my post making it look like I had ran 4 hours at WOT. However, schooling me on it (swaterhouse) was not at all helpful. Last thing anyone wants after this kind of damage is someone telling him he was stupid when they ask for help! :(
     
    JC3 and The Bill Collector like this.
  12. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars
    Sorry, I'm just seeing this.....I've been on the boat all day. Since I am late to the party, I'm not sure I understand what all it going on, so I'm just going to wade in.........

    Why are you removing the turbo? At the sea trial the engines ran up to reasonably close to WOT and they could not do that with a non-functioning turbocharger. Some oil on the intake side of the turbo is normal; excessive oil is likely comes from the crankcase breather that needs cleaning or replacement. It doesn't much diesel oil to look like a whole lot.

    Did you consider checking the condition of the primary fuel filters. A Caterpillar will starve itself of fuel if a Racor is clogged. It won't die, but it will slow down to the point where it's need for fuel is limited by the Racor's ability to process fuel. That sounds exactly like what you have going on...unless I've missed something in trying to quickly catch up.

    No, Caterpillars don't get eaten up by salt water. They do however need the heat exchangers and various coolers cleaned periodically. I clean mine with a descaler about every 5 years........my boat is in perfect mechanical condition on its original heat exchangers, aftercoolers, etc. and it has been in the same slip on the Gulf of Mexico since May, 1996.
     
    Freedom Rider likes this.
  13. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    Hi Frank. We replaced the CAT twist on canister fuel filters along with the oil and air filters. We also cleaned the Racors.

    I tried running port engine with one Racor valve off and the other on and vise-versa, then tried switching the fuel tank to only run on STBD tank since it was running fine thinking it was diesel fuel issue. We had just topped off both tanks with fresh diesel fuel.

    What lead me to the Turbo was the oil leaking into the bilge and tracing the oil source on the engine to the top of the turbo as seen in the pictures. I asked a diesel mechanic who stated no oil should come out the top of the turbo and that indicated bad seals on the turbo. I decided that made sense, even though i hated the answer and decided I was not paying CAT to do it and started removing the turbo.

    By the way, called CAT for a turbo. they dont make it or have it. They do have a brand new model and you have to replace the entire top end of the engine new....$$$ :(

    I found a turbo rebuild company to send mine out to.
     
  14. mpatton

    mpatton New Member

    26
    Mar 17, 2008
    Chicago
    1997 450 DA
    3126 Cats
    I had the same problem a couple of seasons ago, and it was fuel deprivation (filters). Cat was on my boat today, and I had a little of the oil like yours, and they said it didn't appear to be a problem. They did a valve/lash adjustment $775 which seemed very fair for Chicago (just FYI).
     
  15. Wistlindixie

    Wistlindixie New Member

    22
    Jun 18, 2018
    Michigan
    450 DA
    CAT 3126
    $775 valve lash adjustment sounds incredible.

    At this point I have everything disconnected from the turbo because I can’t see a turbo that leaks oil as ok. It shouldn’t be leaking past. As much as I hate it, I want it working on July 4th. It’s coming out one way!!

    So... I think the exhaust manifold has to come off first. Then lower the assembly together to remove the turbo on bench.

    Anyone know that detail? What are the removal steps in the service manual? I am willing to buy one from someone, even a copy!
     
  16. ttmott

    ttmott Well-Known Member GOLD Sponsor

    Apr 3, 2012
    Space Coast Florida
    2006 52 Sedan Bridge
    Cummins QSM11
    A couple of nuggets for you to consider -
    Only two sources of oil that the turbocharger sees; bearing oil and crankcase blow-by oil. Either will be noticed on the compressor side of the unit. Did the mechanic do an engine blow-by test? The crankcase ventilation system can deliver quite a bit of oil to the air intake if there is significant blow-by. Assume you have Walker Air-Sep air filters, so if there is large amounts of oil in the filter housings then most likely engine blow-by.
    The Cat 3116 and 3126 do ingest oil into the intake structure (mist from the crankcase) and this is the reason Cat mandates the use of either 30 or 40 weight engine oil only; no multi-viscosity oils. The multi-viscosity oils tend to deposit residue inside of the aftercoolers and over time will restrict air flow.
    What is not clear is where do you think the oil is coming from, the coupling to the aftercooler, the oil hoses on the unit, or the air filter? It looks from the pictures that the oil is coming from the aftercooler coupler...…
    When you say the engine "stalled", are you saying it shut down? Or, not making any power but still running? Also, I'm a bit confused as you also say - when on Sync the "engines" stalled - which indicates both shut down. Maybe some clarification here also....
    As in the testing both engines made power and RPM indicates nothing really mechanical. Did the mechanic do individual engine load test? This is a test to see how many RPM each engine will pull individually; if they are the same then you know each are performing equally.
    So I'm down to several things with the information provided - 1. The synchronizer is dropping out so eliminate that as a potential issue. 2. A fuel delivery issue; I had gotten some bad fuel on my 400DA with 3116's in the Bahamas and the pickup tubes in the tanks were plugging up which caused a very similar issue.
    Regarding the oil; it appears the aftercooler coupling to the turbocharger is not holding pressure; there is a lot of pressure at that coupling, like over 40 psi.
    And, without history all of the engine's coolers should be removed and cleaned and pressure checked; a failure of any one of these can be catastrophic to the engine.
     
  17. fwebster

    fwebster Well-Known Member TECHNICAL Contributor PLATINUM Sponsor

    Oct 6, 2006
    Middle Tennessee ; Panama City Beach, FL
    1996 450DA
    3116 Caterpillars

    Actually, $775 is a bargain for resetting the engine overheads on a 3116/3126.

    Not only are the intake and exhaut valves reset, but on the 3116/3126 the injectors are cam driven so the injector timing is also reset. This is done thru the use of gauge blocks and a dial indicator and it is a 6 to 8 hour job, after the mechanic gets to the boat.
     
  18. swaterhouse

    swaterhouse Active Member GOLD Sponsor

    328
    Jan 7, 2015
    Mattapoisett, MA
    2007 Sundancer 44
    Cummins QSC 8.3
    I apologize for my opening statement, I thought about that Friday night before I fell asleep and felt bad!

    I was based on what you originally wrote helping you understand that running for hours on end at WOT is very bad.

    Good luck, hope you get everything in good running order, your in excellent hands with fwebster!
     
    Boater420 and JC3 like this.
  19. The Bill Collector

    The Bill Collector Well-Known Member SILVER Sponsor

    Jun 2, 2008
    Tacoma, WA
    450 Sundancer
    3126 Cat's
     

    Attached Files:

  20. mpatton

    mpatton New Member

    26
    Mar 17, 2008
    Chicago
    1997 450 DA
    3126 Cats
    My $775 Valve adjustment was NOT accurate. I just got a second invoice, for the second engine.... for $826. Very odd, I've never had Cat bill the engine individually before. Sorry for the misinformation.
     

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