Help With Cat 3406B Issues

Discussion in 'Heavy Duty Diesel Truck Mechanics Forum' started by OldRed98, Dec 26, 2020.

  1. OldRed98

    OldRed98 Light Load Member

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    Good idea... The oil temp gauge isn't working. I'll give it a look and see if I can get it working. A plugged cooler could easily cause this and on a truck this old its very possible.
     
    Rideandrepair Thanks this.
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  3. OldRed98

    OldRed98 Light Load Member

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    Hi Wore out. I've seen your name on may threads I've read about the 3406b. I'm going to take your advice on the 177148 Turbo when I get around to changing the turbo out.

    I hope its not Rods and bearings but its likely the cause.

    The Blowby smells like fuel but could easily be coolant vapor. No liquid (Oil or coolant coming from blowby tube) just white smoke. The first day I started the truck the exhaust smelled super strong like fuel. but after treating the fuel it smells a lot better. Made me wonder how old the fuel must be. Besides the low oil pressure issue, the truck seems to run okay. I haven't driven anywhere beside up my road. I don't want drive off with low oil pressure and without servicing my oil and filters. But sounds like I might be in for a rebuild regardless.

    I put out a message on my local semi truck forum for a good CAT referral. Hard to find the good engine guys anymore (especially knowledgably on old trucks). Most of the shops around here want to work on fleet trucks paying the big bucks.
     
    Rideandrepair Thanks this.
  4. wore out

    wore out Numbered Classic

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    The exhaust smelling like fuel and white smoke is common on cold starts under 35 degrees or so. Shouldn't last over a minute or 2. Any longer than that you have nozzle or timing issues.


    Sorry I meant to address that earlier and forgot
     
  5. beastr123

    beastr123 Road Train Member

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    With the B models a bearing roll is nowhere near a rebuild. I used to get it done at a dealership at 400k intervals and in 94 and 95 the cost was $300 plus parts and oil.
     
  6. Roger McG

    Roger McG Light Load Member

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    If you are going to go thru the trouble of pulling the pan as stated above roll a set of rods and mains in it. Thats just cheap peace of mind
     
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  7. OldRed98

    OldRed98 Light Load Member

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    @Roger McG @beastr123! Thank you! I didn't realize how cheap and simple it is to replace the bearings. Pulling the pan and scraping the gasket is a pain though. I just did it on my N14 last summer. But I would be glad to pay the dealership $300+ parts... I'm sure its a lot more now. Ive never gotten out of the dealer for less than a couple thousand.

    Sounds like a good approach will be 1) oil sample 2) new bearings ... If my low oil pressure persists then I will look at engine timing.

    I've found a couple good CAT mechanics here. Bad part is that they are a couple hours from me.
     
    Rideandrepair, beastr123 and 650cat425 Thank this.
  8. wore out

    wore out Numbered Classic

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    Just to make sure you word it right if you ask the mechanic about it. It's the mechanical timing advance its controlled by oil pressure. Not where the timing is set per say.
     
  9. Anthony Landis

    Anthony Landis Bobtail Member

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    I rolled main and rod bearings into our B model myself. Its not a complicated job and doesn't require any special tools. If I remember correctly I found some good write-ups and or video online explaining the correct procedure.
     
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  10. OldRed98

    OldRed98 Light Load Member

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    I found a good video on installing main Bearings and Thrust Bearings in a CAT motor. Figured this might help someone else down the road. I like this guys youtube channel.



    It will be a couple of weeks before I get around to doing my bearings. Sending my oil sample off this week. I'll post an update once I get a little further progress. Thanks for the help everyone!
     
    Rideandrepair and Roger McG Thank this.
  11. OldRed98

    OldRed98 Light Load Member

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    Oil Analysis .jpg I got results back from my oil sample.

    Looks like the sample shows high lead which indicates bearing wear. Plus with lower oil pressure, I think I am going to get started on the bearings now.

    Also played phone tag with the prior trucks owner who told me the truck had a new headgasket put on last year. I wonder if high copper and silicone have to do with the headgasket replacement.


    Notes from Blackstone:
    Universal averages are based on oil run ~10,800 miles, and compared to those, copper and lead are high. Lead shows bearing wear, while copper can have a variety of sources including brass/bronze parts. Potassium and sodium are from coolant, but there's not a lot of contamination at this point. With elevated lead, though, coolant may have had an effect on wear. Silicon can be dirt or sealers used in maintenance. If the latter, hopefully the coolant is just residual from before repairs. If oil pressure is okay and coolant isn't being lost, try 4K miles for a follow-up.
     
    Last edited: Jan 20, 2021
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