Cat 3406E issues.

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Eric R., Jun 13, 2008.

  1. Eric R.

    Eric R. Bobtail Member

    Jun 13, 2008
    Lake Elsinore, CA
    Hi guys and gals. I'm new to the forum and am in need of some advice. Any help will be greatly appreciated.

    Heres some history. I bought a used dump truck about 3 years ago. Its a 1997 Freightliner with a Cat 3406E with 250 HP. I know the HP sounds pretty low but whoever owned the truck must have had it tuned down. It does what I need it to do though. It had about 408,000 miles on it and it now has 436,000 miles. It used to have a fifth wheel but was converted to a dump truck (frame extended, hydraulics added, and a new dump bed).

    Heres some recent history. For a couple of months I was having water in my fuel issues and rough starts in the morning when I first start the truck for the day (groggy with white smoke for about 5 seconds). Other than the rough first start, the truck ran well with clean exhaust (no smoke and no power loss). I thought I a had sucked up some bad fuel from a gas station during the heavy rains. So I thought it would clear it out with filter changes and fresh fuel. This happened to us once on another truck, so I assumed it was the same issue.

    Well it just wouldn't go away. So I thought maybe someone didn't like me where I park my truck at night and was putting water in my tanks. But, one warm Friday afternoon driving in Los Angeles traffic for two hours, I get back to the yard and there is diesel fuel coming out of my overflow tube from my radiator reservoir.

    So I thought it might be the fuel filter assembly because there is water lines running through it to heat the fuel. I pressure tested it with a water hose and it would not leak.

    So I began to call some mechanics. They said it was a cracked injector tube and that the head needed to be rebuilt and it would cost about $2,500.00.

    Well at least I finally know what the issue is and can get it fixed. So we take it to a shop and they get the head rebuilt ($2,800.00). I drive it home and realize that the coolant temperature gage isn't working and that my fan clutch is stuck on. I call the shop and they said to bring it back in.
    I had jobs I needed to do so I ran the truck until I had some time to bring it back in. On the second day after picking it up an injector failed. The piece in the end of the rocker arm had turned sideways and jammed the injector valve open. Why would this happen??? Did they not adjust the clearance properly??? Does anybody know why this happened right after they rebuilt the head???

    So I run to the Cat dealer and get a re-manufactured injector and other parts needed so I can get back to work the next day (about $550 for parts). They put it in and it ran good but we still had the temp gage not working and the fan stuck on. They tried to trouble shoot it, but it was like 7:00 pm and I had to get home and I had a job to still finish.

    Within the next couple of days I buy a new temperature sending unit ($30) and now my temp. gage works again, but the fan clutch is still on.

    Then I buy a fan clutch sensor ($100) and replaced it but it did not fix the fan clutch.

    I tested the fan clutch solenoid and it works fine at 12.2 volts but the signal wire to the solenoid is only bringing 11.2 volts!

    So, should the solenoid be able to function at 11.2 volts or is the ECM not putting out the proper voltage????? How do I fix this issue?

    Heres a summary of things I would like opinions on. Feel free to add anything else.

    1. Is the shop responsible for the failed injector after the head rebuild?

    2. Are they responsible for temp. the sensor and fan issues?

    3. How can I trouble shoot and fix the fan staying on constantly issue?
  2. Diesel Smoke 84

    Diesel Smoke 84 Bobtail Member

    Mar 29, 2008
    La Pine, Oregon
    The solinoid most likley cant function at 11.2 volts. They dont tand to have a very big operating range.

    I would hol the shop responsible for the injector but the sending unit and fan clutch is up to you if you want to push the subject.

    Check and see if you some how got a new fan clutch sensor that was already bad. I rebuild a lot engines for the Army (Cat, Detroit, Cummins ect) and with as much parts as we order you do get parts that are no good from the factory more often then you would think!

    good luck!
  3. 550hpW900L

    550hpW900L Road Train Member

    Jan 29, 2008
    I would hold the shop responsible since it left their shop, especially a mechanical injector failure, they had to take the fan hub off to get the head off, so its likley they screwed with that as well. Oh by the way, no way is your 3406E is set to 250hp, lowest they go is 370.
  4. pcfreak

    pcfreak Heavy Load Member

    Apr 22, 2007
    Alberta, Canada
    Actually I've seen trucks with 3406e motors at around 355hp.

    Even some lower than that.
  5. Eric R.

    Eric R. Bobtail Member

    Jun 13, 2008
    Lake Elsinore, CA
    Thanks for the reply guys.

    Diesel Smoke 84: How can I tell if the fan clutch sensor is bad? I tested its votage going to the sensor and I got 6.5 volts from one wire, 4.3 volts from another, and nothing from what Im assuming is a ground wire.

    550hpW900L: I think you may be right on the HP. Maybe its 350 HP.

    Where is this signal coming from thats telling the air solenoid to open and close???
  6. Eric R.

    Eric R. Bobtail Member

    Jun 13, 2008
    Lake Elsinore, CA
    Well I found out why the fan was staying on.
    Someone on another forum pointed me in the right direction.
    They said check out the air conditioning because it is also tied into the ecm.
    My truck has an APADS ( air conditioning controller. Well looking at the controllers blink code, it was telling me it had low voltage which means the default action is to run the fan. The APADS website had great trouble shooting guides and manuals to help diagnose issues. So I began running through the trouble shooter and was trying to figure out why the APADS had no main voltage and no ground.
    Well the mechanics plugged the APADS into the only possible wrong plug for the system power and ground. There just happens to be a spare plug coming out of the firewall near the APADS that appears to be for a unused device. The actual they needed was coming from the other side of the engine.
    Thanks for your help guys. I hope this helps someone in the future.
    Big Duker Thanks this.
  7. Moving on Down the Road

    Moving on Down the Road Light Load Member

    Mar 6, 2010
    Eric... not at all trying to hijack you're thread here, but if you or any others happen to know.... I'm sorta experiencing the same problem except my fan won't go off above a certain temp. I run long haul from KY to Houston and with the hot unusually hot and humid weather, it simply won't turn off till late at night if it gets below about 80 degrees. It's eating my fuel up and I'm afraid it's going to destroy the clutch. I've had the truck for over 5 years and have never had this problem. Tks...... Gil
  8. Krooser

    Krooser Road Train Member

    Jul 25, 2010
    It won't hurt the clutch as it's full on right now...I'm going to replace my fan clutch this week as I'm having the same snafu as you right now.
  9. Eric R.

    Eric R. Bobtail Member

    Jun 13, 2008
    Lake Elsinore, CA
    I dont have this truck anymore but I will try to help you.

    Maybe you have a bad fan clutch sensor?

    This is different than the temperature sensor that shows you how hot the coolant is on the dash board. I believe the fan clutch sensor is independent and tells the fan when to turn on and off.

    On the side of the water pump housing there is I believe 2 sensors. The water pump is on the top, front, right side of the engine. The sensors screw into the side of the water pump and each has its own wiring harness plugged into it.

    Than fan clutch sensor was a $100 part at the Freightliner dealer when I bought it. By the way, this part I couldnt return because it was electronic.

    I would buy this part and swap it out. Your time and this part would be cheaper than taking it to a shop.

    Also, to get the sensor off. You will need to buy and sacrafice a deep socket. In order to get the sensor off, you have to grind slit up the side of the socket to accomodate the wires of the sensor.


    Let me know if you have any more questions.
  10. Gambino1994

    Gambino1994 Light Load Member

    Jan 22, 2009
    causing a situation
    on my 3406e i over charged the ac system and the fan would stay on all the time if i had the ac on. i then bled off some pressure off the high press. ac line and that fixed my problem. good luck
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