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08 5.7 running hot at 2000 to 2500 rpm

Discussion in '2nd Gen Tundras (2007-2013)' started by Rodney mc, Dec 7, 2020.

  1. Dec 7, 2020 at 6:06 PM
    #1
    Rodney mc

    Rodney mc [OP] New Member

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    I changed the radiator, thermostat, Belt, Clutch fan is fine, Collant is full also changed the Radiator cap,

    The truck running at 2000 rpm gets 3/4 hot if I put the truck in Netural and rever it up it quickly goes back to less than halfway. I was thinking the fan blade on the water pump might be worn out not getting enough water to flow through the engine, Or there is a blockage somewhere slowing the water down because when you turn more RPM like 3000 it cools back down.

    Open to any and all subjections.

    Thank You
     
  2. Dec 7, 2020 at 6:17 PM
    #2
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    Clutch fan may be failing?? Do you get any heat??
     
  3. Dec 7, 2020 at 6:40 PM
    #3
    Johnsonman

    Johnsonman New Member

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    LED headlamps/fogs; interior footlamps.
    +1 on the fan clutch
     
  4. Dec 7, 2020 at 7:53 PM
    #4
    Rodney mc

    Rodney mc [OP] New Member

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    The clutch fan is good, I get plenty of heat, thinking it has to be some sort of blockage.
     
  5. Dec 8, 2020 at 3:24 AM
    #5
    Gto7419

    Gto7419 New Member

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    Check compression.
     
  6. Dec 8, 2020 at 5:54 AM
    #6
    Rodney mc

    Rodney mc [OP] New Member

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    Forgot to mention I am not losing any water, I will check compression, just curious if compression is low how would that make the water run slower through the system so when I turn more RPM it runs kooler.

    Thank You
     
  7. Dec 8, 2020 at 5:56 AM
    #7
    Rodney mc

    Rodney mc [OP] New Member

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    Just had a thought what if the heater core is stopped up somewhat, I have good heat but it could be slowing down through the heater core?
     
  8. Dec 8, 2020 at 7:21 AM
    #8
    CreekDweller

    CreekDweller Not so new ...

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    I'm speculating here, but I wonder if it might be your water pump. For example: At low engine speeds the engine is not producing a lot of heat so the temperature remains in the normal range. At 2000 RPM, more heat is created by the higher RPM, but if you have a weak water pump, there may be insufficient coolant flow to keep the engine temperature down. When you rev to higher engine RPM, the water pump may now turn fast enough to circulate sufficient water to keep the engine cool.

    Not sure if this theory is valid, but it might be worth checking out since nothing else is evidently wrong.
     
  9. Dec 8, 2020 at 7:24 AM
    #9
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    If that was the case, you would have no heat.. My SC400's heater core just got unclogged magically by stomping the gas and getting some heat instantly...
    If you feel something is clogging your cooling system, check your radiator cap and make sure its intact... My old one had a chunk still missing, but no issues as of yet...
     
  10. Dec 8, 2020 at 7:53 AM
    #10
    Rodney mc

    Rodney mc [OP] New Member

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    I agree that is my thought process too, Radiator cap is new, maybe the blades on the water pump could be worn, I just got this truck and was told it had over 300,000 miles but it was free so I don't mind putting some money into it. I guess thinking about it the heater core if it was partially stopped up would that slow down the water enough to let it get hot? I do have heat but then again I don't use the heat that much anyway.
     
  11. Dec 8, 2020 at 1:39 PM
    #11
    Johnsonman

    Johnsonman New Member

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    What are you using to determine coolant temps? Can't trust dash gauge much. I use the torque/odb2.

    I don't understand the correlation between 'having enough heat from heater' and the fan clutch being 'OK'.

    If clutch is original, i find it highly suspect. Just trying to help mahn, Luck.
     
    Dalandshark likes this.
  12. Dec 8, 2020 at 6:28 PM
    #12
    Dalandshark

    Dalandshark Infected with 5G

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    +1 on needing to verify temps. Maybe verify temp sensor is good too, should be able to put in ice water or something and read ohms. Cooling system pressure test? Collapsed hose (I see this in comments a lot but don’t know it’s actually a thing)?
     
  13. Sep 22, 2021 at 10:32 AM
    #13
    Nathanielk

    Nathanielk New Member

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    Any resolution her? I have 2008 5.7 exact symptoms. Replaced raditor, clutch fan, water pump, and thermo. Engine has always run just below 1/2 line. Now it gets hot/ warm when in drive at 1500 rpms. If I down shift to 3rd, it cools down. If I put in neutral and rev it cools. I did a pressure test and chemical test. No blown head gasket
     
  14. Sep 22, 2021 at 10:53 AM
    #14
    audiowize

    audiowize New Member

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    These are the expected symptoms of air bubbles in the system.
     
  15. Sep 22, 2021 at 11:07 AM
    #15
    Forcefed

    Forcefed New Member

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    I seconded the air bubbles in the system. Both have just opened the system to replace something. I bet you both have air bubbles.
     
  16. Sep 22, 2021 at 11:09 AM
    #16
    blackdemon_tt

    blackdemon_tt Battery Slayer

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    I would agree... if there are block bleeds I would crack those and dip the long hoses inside a container with coolant as to prevent air to come back in...
     
  17. Sep 22, 2021 at 4:30 PM
    #17
    NueveTundra

    NueveTundra Mod list in Bio

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    Exterior: Toytec ultimate 3" lift level, Total Chaos Uniball UCA's, Total Chaos Cam Tab Gusset kit, AcanII smoked headlights, AcanII smoke Tail lights (2.5 gen style), DV8 front winch bumper , Badlands 12k winch with Apex Synthetic, White AUTMATCH Shackles 3/4" D Ring Shackle, Apex Winch shackle, Trail Ridge mirrors ,Icon Rebound Pro 17"x8.5" +25, Cooper Discovery STT Pro 285/70R17, PowerStop drilled n slotted rotors W/Carbon pads, Rigid flood flush mounts rear bumper , WeatherTec rain guards , OEM black side badges , Rigid Amber Radiance Pods. Energy Suspension Red Rack and Pinion Bushings, EAG front mesh Grille, RCI HighLift bed mounts. Rough Country DS2 Steps, A.R.E OverLand Canopy with Ascend basket, Stickers: ToyTec lifts windshield banner, Red Strange Music window sticker(back cab), White Strange Music sticker(back canopy), White Rigid sticker x2 (canopy sides), white Official BigFoot Research Team (Back Canopy) Interior: Alpine double din touch iLX-650 , JL C5-653's (front) JL C1-650x (rear) , JL JX400 4 channel amp , JL JX500 mono amp , 2 JL 12" subs , WeatherTec floor mats, Kenwood F/R Dash Cams, Black steering wheel emblem overlay, Tekonsha P3 Brake controller, ToyTec "Fresh" Scent coilover air freshener, Under the Hood: Koyo all aluminum radiator, Mishimoto red silicon hoses , XS Power 3000 amp battery , LAlectric 300 amp Alternator , K&N replacement filter. Online LED store accessories Fuse/relay box. (Identified) Dirty Deeds 8" Cat back exhaust with DD resonator delete/axel over converted into dump. Coming soon:
    After the change of cooling system parts did you elevate the front end only with with cap off and heat on full blast and let run for 5 minutes per Toyota service manual for bleeding air?
     

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