1. Welcome to Tundras.com!

    You are currently viewing as a guest! To get full-access, you need to register for a FREE account.

    As a registered member, you’ll be able to:
    • Participate in all Tundra discussion topics
    • Transfer over your build thread from a different forum to this one
    • Communicate privately with other Tundra owners from around the world
    • Post your own photos in our Members Gallery
    • Access all special features of the site

Rad cap broke apart, pieces in rad, now what!?!

Discussion in '1st Gen Tundras (2000-2006)' started by Hoferkill, Jul 8, 2025 at 6:14 PM.

  1. Jul 8, 2025 at 6:14 PM
    #1
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    2006 4.7 liter V8 213,000 miles
    Help!
    So I just happened to take my rad cap off tonight and noticed a spring lying inside on top of the rad core.
    No idea when this happened. Looks like the rad cap plastic sleeve broke off. Assuming there are still pieces inside my rad?
    What do I do now? Pull all the hoses? Not even sure what parts I'm even looking for!

    PXL_20250709_002333837.jpg
    PXL_20250709_001431281.jpg
    PXL_20250709_002355497.jpg
     
  2. Jul 8, 2025 at 6:20 PM
    #2
    Jack McCarthy

    Jack McCarthy Working remotely from the local pub

    Joined:
    Nov 2, 2020
    Member:
    #54409
    Messages:
    10,646
    Gender:
    Male
    First Name:
    Bill
    North of Boston
    Vehicle:
    02 Tundra AC SR5 V8 4x4
    That’s gonna be fun to fish out the broken piece. I’d have to take a look, but I thought it was a metal plate bottom the spring attached to create a good seal by forcing the cap upwards.
     
    Hoferkill[OP] likes this.
  3. Jul 8, 2025 at 6:23 PM
    #3
    Jack McCarthy

    Jack McCarthy Working remotely from the local pub

    Joined:
    Nov 2, 2020
    Member:
    #54409
    Messages:
    10,646
    Gender:
    Male
    First Name:
    Bill
    North of Boston
    Vehicle:
    02 Tundra AC SR5 V8 4x4
    Something like this from a 4runner?

    IMG_1647.jpg

    Looks like you have the plate, it’s the plastic piece as you suggest.
     
    Hoferkill[OP] likes this.
  4. Jul 8, 2025 at 6:36 PM
    #4
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Yes, I have the metal ring/rubber seal, and the spring. It looks like the plastic tube that the metal ring fits over broke off. I guess next steps would be to take a peek with a scope... And then start pulling hoses?
    Too tired to look at it tonight.. guess I'll just toss and turn thinking about it!
     
  5. Jul 8, 2025 at 6:38 PM
    #5
    Jack McCarthy

    Jack McCarthy Working remotely from the local pub

    Joined:
    Nov 2, 2020
    Member:
    #54409
    Messages:
    10,646
    Gender:
    Male
    First Name:
    Bill
    North of Boston
    Vehicle:
    02 Tundra AC SR5 V8 4x4
    Makes sense. I just don’t know what it would take to fish it out of there if it’s even possible. At least if it was attracted to a magnet you’d have a chance.
     
    Hoferkill[OP] likes this.
  6. Jul 8, 2025 at 6:45 PM
    #6
    Sirfive

    Sirfive Socially feral

    Joined:
    Jan 24, 2021
    Member:
    #58078
    Messages:
    5,368
    Gender:
    Male
    SATX
    Vehicle:
    ‘02 Limited AC TRD
    Bassani cat-back
    Since its on top, you might be able to flush it out, but i wouldnt really worry about it, i doubt it’ll hurt anything.
     
    Hoferkill[OP] likes this.
  7. Jul 8, 2025 at 6:49 PM
    #7
    assassin10000

    assassin10000 New Member

    Joined:
    Oct 27, 2020
    Member:
    #54157
    Messages:
    2,253
    First Name:
    Andrew
    Northern CA
    Vehicle:
    '05 SR5 AC
    Remote start alarm Removed keyless entry piezo Qi phone charger & dash mount Subaru underseat subwoofer Hopkins Easylift Steering wheel audio controls No-tenna mod 3/4 adhesive anti-rattle shim D/S door
    Coolant enters the top hot and goes down to the bottom to return iirc.

    That piece won't make it into/past the core (finned portion of the radiator), so I wouldn't worry about that little plastic and rubber piece.
     
    G_unit3000 and FrenchToasty like this.
  8. Jul 8, 2025 at 6:51 PM
    #8
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Hmmm, if it's like a plastic washer like the pic that Jack attached, I wonder if it floats. Jack up the left side, pour in antifreeze, and watch for it by the cap hole?
     
    Jack McCarthy likes this.
  9. Jul 8, 2025 at 6:52 PM
    #9
    Fragman

    Fragman New Member

    Joined:
    Nov 28, 2024
    Member:
    #126540
    Messages:
    316
    Gender:
    Male
    TX
    Vehicle:
    2006 Tundra DC SR5 2WD V8
    If your radiator is original or the plastic has 'gone brown', you might want to think about replacing it anyway.
     
  10. Jul 8, 2025 at 6:53 PM
    #10
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Now that you mention that, it makes sense! That's comforting!
     
  11. Jul 8, 2025 at 6:55 PM
    #11
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    This truck is new to me and my first Toyota.. how do I tell if it's original? What color was it before "gone brown"?
     
  12. Jul 8, 2025 at 6:56 PM
    #12
    Fragman

    Fragman New Member

    Joined:
    Nov 28, 2024
    Member:
    #126540
    Messages:
    316
    Gender:
    Male
    TX
    Vehicle:
    2006 Tundra DC SR5 2WD V8
    Black
     
    Hoferkill[QUOTED][OP] likes this.
  13. Jul 8, 2025 at 6:59 PM
    #13
    Fragman

    Fragman New Member

    Joined:
    Nov 28, 2024
    Member:
    #126540
    Messages:
    316
    Gender:
    Male
    TX
    Vehicle:
    2006 Tundra DC SR5 2WD V8
    From the master thread So ... you wanna buy / just bought a 1st Gen Tundra, eh? | Toyota Tundra Forum

    • Get to a baseline on critical 1st-Gen-Killer maintenance items that needed to be done:
      • Timing belt/water pump/pulleys/tensioner needs to be done every 9yrs/90k miles.
      • Radiator should be done every 125k-150k miles.
      • OEM lower ball joints should be done every 100k-125k miles *IF* they're OEM parts (aftermarket LBJ shouldn't be used, and should be replaced immediately).
     
    G_unit3000 and shifty` like this.
  14. Jul 8, 2025 at 7:06 PM
    #14
    Fragman

    Fragman New Member

    Joined:
    Nov 28, 2024
    Member:
    #126540
    Messages:
    316
    Gender:
    Male
    TX
    Vehicle:
    2006 Tundra DC SR5 2WD V8
    Basically it's to protect your tansmission. The transmission lines go through the radiator and the joints inside the radiator tend to give way after many years. Then coolant mixes with the transmission fluid and you've got pink milkshake for ATF.
    But, as the plastic on top of the radiator ages, it turns brown through oxidation. That's kind of an indicator that its pretty old and probably needs to be replaced.
     
    G_unit3000, shifty` and Hoferkill[OP] like this.
  15. Jul 8, 2025 at 7:21 PM
    #15
    PNW15

    PNW15 New Member

    Joined:
    Aug 19, 2023
    Member:
    #102399
    Messages:
    274
    Gender:
    Male
    WA
    Vehicle:
    2006 DC V8 4WD
    Upload a picture of your engine bay and radiator.

    From the area around the cap it looks old
     
    Hoferkill[QUOTED][OP] likes this.
  16. Jul 8, 2025 at 7:37 PM
    #16
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Thanks, will do tomorrow. Been oil sprayed every year for the last 14 years so everything is just dripping in oil.
    I do have some service records to peruse.. I know the timing belt was replaced at Toyota and should be good for 40 k. UBJs are yotas and new, lowers where done under recall and still seem tight, but probably getting due too.
    Thanks!
     

    Attached Files:

  17. Jul 8, 2025 at 7:47 PM
    #17
    Redoak

    Redoak New Member

    Joined:
    Nov 28, 2024
    Member:
    #126549
    Messages:
    156
    Gender:
    Male
    First Name:
    Dave
    Vehicle:
    2006 Toyota Tundra DC, Limited 4x4, with LSD
    none
    If radiatior cap came apart I'd be thinking its sign to also replace radiator.
    A Denso at rock auto runs around $130.
     
    Hoferkill[OP] and jerryallday like this.
  18. Jul 9, 2025 at 4:10 AM
    #18
    NickB_01TRD

    NickB_01TRD You don't need less cars, just more driveway.

    Joined:
    Jun 16, 2021
    Member:
    #64346
    Messages:
    2,745
    Gender:
    Male
    First Name:
    Nick
    KY
    Vehicle:
    01 Tundra V8 4X4 AC SR5 TRD
    The rad cap in my 96 camry came apart entirely.
    I may have gotten one piece out but I just left the rest and haven't had any negative effects.
     
    Hoferkill[OP] likes this.
  19. Jul 9, 2025 at 4:45 AM
    #19
    bfunke

    bfunke Tundra Curmudgeon

    Joined:
    Oct 13, 2019
    Member:
    #37321
    Messages:
    2,516
    Gender:
    Male
    First Name:
    Bryan
    South Carolina
    Vehicle:
    2018 SR-5 CM 5.7, 2000 SR-5 AC 4.7L
    It should remain in the top tank. If you want to get it, remove radiator, hold inverted and shake. It should fall out. Get new OEM cap. Radiator looks brown in your photo. How many miles? Consider replacing radiator. Use only Denso which you can get from RA or Summit.
     
    PNW15 and Hoferkill[OP] like this.
  20. Jul 9, 2025 at 7:43 AM
    #20
    ATBAV8

    ATBAV8 New Member

    Joined:
    Dec 1, 2023
    Member:
    #107779
    Messages:
    887
    Tempe, AZ
    Vehicle:
    2003 V8 SR5, Access Cab, 4x4, White
    That radiator needs to be replaced in the near future anyway. Now would be a good time to do it. Think about why that cap fell apart. There must be some corrosive potential in your coolant. Now think about the rest of the radiator. Guessing they're the same age. It could just be the photo, but that coolant doesn't look right either. Looks like some green and pink were mixed. Don't bother trying to fish anything out. You can probably drive it temporarily, but replacement with OEM radiator and cap is the only option I would consider.
     
  21. Jul 9, 2025 at 7:44 AM
    #21
    shifty`

    shifty` We call it “riding the gravy train”

    Joined:
    Jun 20, 2020
    Member:
    #48239
    Messages:
    29,985
    ATL
    Vehicle:
    '06 AC Limited V8/4WD
    (see signature for truck info)
    Dude. Your radiator is brown as shit. It's supposed to be black. Browning radiator plastics is a sign you've waited waaaaaay too long to replace your radiator with a new Denso brand unit.

    Please replace your radiator ASAP.

    I saw a 1st gen (in really rough shape) in the display area at Caffeine & Octane this month, hood open, radiator was similarly brown. The owner was nowhere to be seen, so I couldn't chat him up. The three 1st gens there (which is unusual to even see a single truck) were really not in good shape. Made me think I should probably be showing my truck :rofl:
     
  22. Jul 9, 2025 at 7:48 AM
    #22
    shifty`

    shifty` We call it “riding the gravy train”

    Joined:
    Jun 20, 2020
    Member:
    #48239
    Messages:
    29,985
    ATL
    Vehicle:
    '06 AC Limited V8/4WD
    (see signature for truck info)
    Timing belt, if you use OEM parts (either Toyota direct or the Aisin TKT021 kit), is good for 90k miles or 9yrs according to Toyota. You can no doubt skate to 100k or 10yrs, but ...

    If using aftermarket parts, I wouldn't dare, but you'd be best to change every 40k miles. But I think you'd be crazy to (A) only change the belt, not the tensioners, pulleys, water pump, and (B) you'd be crazy not to use the Aisin kit, which comes with all that stuff, for way cheaper than aftermarket suppliers.
     
    Hoferkill[QUOTED][OP] likes this.
  23. Jul 9, 2025 at 7:48 AM
    #23
    ATBAV8

    ATBAV8 New Member

    Joined:
    Dec 1, 2023
    Member:
    #107779
    Messages:
    887
    Tempe, AZ
    Vehicle:
    2003 V8 SR5, Access Cab, 4x4, White
    I can't believe people are actually showing these trucks! I'm with you, and if this is the case, mine could win best of show!
     
    shifty`[QUOTED] likes this.
  24. Jul 9, 2025 at 7:50 AM
    #24
    shifty`

    shifty` We call it “riding the gravy train”

    Joined:
    Jun 20, 2020
    Member:
    #48239
    Messages:
    29,985
    ATL
    Vehicle:
    '06 AC Limited V8/4WD
    (see signature for truck info)
    I need to take pics next time. Seriously. But they had an Aston Martin Valkyrie there, and a La Ferrari, kinda makes our trucks look like, "oh hey there, beater" even when polished up as mine is, so I almost feel silly snapping pics of very average-looking 20 year old, under-maintenanced 1st gens.
     
    ATBAV8[QUOTED] likes this.
  25. Jul 9, 2025 at 12:43 PM
    #25
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Thanks everybody!
    Agreed, rad is definitely turning brown, I can see the color change from where the cap fits to the upper tank. Best price I've found so far is about 367$ Canadian from rock auto. Guessing this would be a good time to change out the thermostat too. Any favorite brands for cap and thermostat?
    Coolant is pink, is that correct?
    Again, thanks everyone for your help!
     
  26. Jul 9, 2025 at 1:04 PM
    #26
    shifty`

    shifty` We call it “riding the gravy train”

    Joined:
    Jun 20, 2020
    Member:
    #48239
    Messages:
    29,985
    ATL
    Vehicle:
    '06 AC Limited V8/4WD
    (see signature for truck info)
    OEM, and OEM, or if Aisin makes it, then Aisin brand. Just don't make the mistake of ordering your parts on scAmazon or fleaBay, kings of counterfeit parts.

    Correct, Pink SLLC.

    And radiator parts, you may be able to shop around in the country. This is your OEM part: https://autoparts.toyota.com/products/product/radiator-assy-164000f040

    Verify fitment before purchase, your local dealer may have it cheaper than Rock Auto. Else, you may shop around to your local auto parts stores and see if they can get it cheaper, the part number to share with them is the "CREW CAB" number here:

     
    Hoferkill[QUOTED][OP] likes this.
  27. Jul 9, 2025 at 3:05 PM
    #27
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    Color me shocked, dealer is cheaper!?!??
    Looks like the 16400-0F040 is discontinued up here, but the one that seems to be called up for a double cab is like 308$ with tax.

    Agree with the comment regarding the jungle website and evilbay!!
    Screenshot_20250709-174920.png Screenshot_20250709-175638.png Screenshot_20250709-174920.png Screenshot_20250709-175638.png
     
  28. Jul 10, 2025 at 4:34 AM
    #28
    Hoferkill

    Hoferkill [OP] New Member

    Joined:
    Feb 24, 2025
    Member:
    #130890
    Messages:
    19
    First Name:
    Hofer
    Vehicle:
    2006 blue DC SR5 4.7l auto Tundra
    Stock as far as I can tell with 211,000 miles
    So in real life it doesn't look quite this brown, but I suspect it's original and will be replaced.
    Thanks!

    PXL_20250709_191248338.jpg
     
  29. Jul 10, 2025 at 5:37 AM
    #29
    KNABORES

    KNABORES Sarcasm incoming

    Joined:
    Jan 1, 2020
    Member:
    #40572
    Messages:
    14,524
    Gender:
    Male
    Arkansas
    Vehicle:
    2000 Limited TRD AC 4X4 Thunder Grey 278k miles. *SOLD* 2019 Limited TRD CM 4x4
    Bilstein 5100's on the forbidden notch Husky HD rear leafs 16x8 Eagle Alloy 187's with 285/75/16 MagnaFlow 3" flow through Pioneer touchscreen with backup camera Full interior and dash LED conversion Trailer brake controller with 7 pin Bedliner coat bumpers & trim ARE Mpulse topper - Rhino Vortex rack
    That is exactly how brown it is. It is time for sure. Word of caution, trying to reuse the hoses or clamps may not work out. My clamps would no longer seal the hoses after replacing them. So new radiator, hoses and clamps is the best bet. I ended up adding worm drives (not ideal) to seal my hoses so I didn't have to wait for new OEM ones or open the system again.
     
    Hoferkill[QUOTED][OP] and PNW15 like this.

Products Discussed in

To Top