DIY Coolant Valley Leak Repair

[Gx460 2013]

Help - I broke all the Knock Sensor Cable Clips (the ones threaded on the torx bolts). What is the part number for these things?

These are the grey things on the Torx bolts. Instead of removing the torx bolts, I broke the plastic clips screwed onto the torx bolts (on the valley plate cover)

 

[r2m]

Help - I broke all the Knock Sensor Cable Clips (the ones threaded on the torx bolts). What is the part number for these things?

Sorry to hear that. Try one of these links to the FSM and part numbers, below:
GX 460 Manuals
GX460 OEM Part Numbers

 

[mikehighlife]

For those in the Bay Area, Lexus of Pleasanton quoted $4k so we DIYed

 

[flawedGX]

This write-up helped me greatly and if the OP is still around thanks a million!! Just finished the job following it step-by-step... including breaking the secondary air tube lol! Couldn't have done it without you.

 

[Gx460 2013]

Does anyone know what this grey plastic thing is called - it is threaded onto the torx bolt (on the valley plate cover) and holds the knock sensor harness in place.
I'm looking for the part number for this grey plastic thing.

 

[Acrad]

Harness connector

 

[Gx460 2013]

Just completed this repair on a 2013 GX460.

Thank you for these instructions, I followed them and got it to work, saving thousands of dollars.
So far, I now have 100 miles on the car with no leak and no error codes (anymore).

Here are my notes - incase they might be useful.

Tool & Parts Purchased Before the Work (for 2013 GX460)

• NEIKO 31121A High Flow Air Blow Gun (Amazon)- from Faye's Repair Video
• GEARWRENCH Angled Hose Clamp Pliers - 3977 (Amazon) - from Faye's Repair Video
• Valco Cincinnati 71006 Tube-Grip 2.5" Industrial Size Dispenser (Amazon) - from Faye's Repair Video
  
  
• 3 Gallons distilled water
• 00295-00103 Toyota Seal Packing 103 (FIPG), 2.0 FL OZ - it was black.
• 12204-38010 PCV Valve Assembly
• 00272-SLLC2 Toyote Coolant - 3 gallons (from Amazon)
• EGR Heat Exchanger Gaskets
  • 25685-38010 (1x)
  • 25629-38010 (1x)
• Manifold Gaskets
  • 17171-0S030 (2x)
• O-Rings
  • 96761-35035 (2x)
• Permatex O-ring Lubricant (8101)

Repair Notes & Pics

• Intake Manifold Problem
  • A mouse dragged lint and palm dates around my intake manifold that we couldn't see. I should have blown out the sides with compressed air before removing the intake manifold.
  • Palm dates got into my intakes. We carefuly vacummed them out and checked result with a boroscope.
• Draining Coolant Problem
  • I should have turned my wheels to the right before starting this repair, to make draining all the coolant easier.
  • Drained coolant from engine following Jonathan Morgan's video: Jonathan's drain coolant video
• Used Permatex 8101 O-ring lubricant on the 2 o-rings.
• We oversized the FIPG bead and let it cure for about 30 hours.

• After the repair, we added 2.5 gallons distilled water through the radiator, ran it awhile, and then drained it before adding 2.5 gallons coolant.

Problems - broken knock sensor harness clip work around

• I broke all the knock sensor harness clips while removing the harness and replaced them with 1/4" and 1/2" insulated cable clamps and metric nuts. It worked fine.
  • Broken Knock Sensor Harness Clips:

• Replaced with insulated cable clamps from Lowes Hardware & Amazon (1/4" and 1/2"). You can cut a 1/2" clamp to be a 1/4" clamp

  

  

Error Codes and Resolutions

• Check Engine Light and 4LO
  
  • Resolution: disconnect positive and negative leads from battery. Touch positive and negative (disconnected) leads together. Reattach both leads to the battery.
• Energizing Car while Disassembled Codes
  
  • P0123 (Throttle Pedal Position), P0113 (Intake Air High), P0108 (Manifold Pressure Circuit) - permanent codes
    • Cause: These codes seem to have been caused by me energizing the electrical system while everything was disassembled.
    • Resolution: Less than 99 miles of city driving and these disappeared.
  • P0102 (Mass Air Circuit Low) - permanent code
    • Cause: P0102 also seems to have been caused by me energizing the electrical system while disassembled.
    • Resolution:
      • Drive exactly 50 mph (for ~ 30 seconds?), then floor it and maintain 65-70 mph for at least 5 seconds
        • I had to do this several times (using about 1/8 tank of gas).
        • I had to turn the car off and back on before the codes went away.
      • This video explains how to clear P0102: Joe Howto's Clear P0102 error code
• DIrty Exhaust Gas Recirculation Valve Codes
  • P0401 (Exhaust Gas Recirc Flow) AND P1604 (Mass or Volume Airflow )
    • Cause: Spraying carb cleaner into the valve's pipes without disassembling the whole thing caused carbon to accumulate at the valve.
      • Dirty Valve Pic:
      • 
    • Symptoms: Rough idle, sulfur smell after 2 miles of city driving, hard start, stalling
    • Resolution:
      • Disassemble and clean EGR valve with carb cleaner. GX BoB's Video: Clean & Install EGR Valve Video
      • Bought 2 more gaskets:
        • 25628-38020 (EGR valve Inlet Gasket)
        • 25627-38020 (EGR valve Outlet Gasket)
      • Torques: 7 ft lbs, 15 ft lbs, much less than 7 ft lbs for the plastic valve head (don't break it).
      • Re-assembly order matters.
      • I followed GX BOb's instructions exactly for re-assembly and P0401 went away.
      • I removed the plastic valve head as well during cleaning, to push the stem/open the valve.

Comments on Vendors

• Many online parts dealers have incomplete diagrams.
• ToyotaPartsExpress.com had great service but incomplete diagrams.
• rallyelexus.com had the best diagrams (and decent service).

 

[jmanscotch]

This write-up helped me greatly and if the OP is still around thanks a million!! Just finished the job following it step-by-step... including breaking the secondary air tube lol! Couldn't have done it without you.

Glad it’s still helping my GX brothers. Cheers man.

 

[kamranrafi]

Thanks for the write up. I am facing similar issue with my 2015 GX with 200K KMs. I have been quoted too much from a well known garage. However there are other small garages they are quoting me 4 times less than the famous one. Following through the post gave me a sense that this is a time consuming task but not too difficult that a normal garage cannot handle it. A bit confused what to do. Moreover I have been given a list of parts which would be needed, I just want to check if all these are necessary to be replaced or only the one's mentioned at start of the write up will suffice?

 

[kamranrafi]

Glad it’s still helping my GX brothers. Cheers man.

Thanks for the write up. I am facing similar issue with my 2015 GX with 200K KMs. I have been quoted too much from a well known garage. However there are other small garages they are quoting me 4 times less than the famous one. Following through the post gave me a sense that this is a time consuming task but not too difficult that a normal garage cannot handle it. A bit confused what to do. Moreover I have been given a list of parts which would be needed, I just want to check if all these are necessary to be replaced or only the one's mentioned at start of the write up will suffice?

 

[jmanscotch]

Thanks for the write up. I am facing similar issue with my 2015 GX with 200K KMs. I have been quoted too much from a well known garage. However there are other small garages they are quoting me 4 times less than the famous one. Following through the post gave me a sense that this is a time consuming task but not too difficult that a normal garage cannot handle it. A bit confused what to do. Moreover I have been given a list of parts which would be needed, I just want to check if all these are necessary to be replaced or only the one's mentioned at start of the write up will suffice?

View attachment 4075954

I see no notable excess parts with that list.

If I recall, I didn’t replace the throttle body gasket nor fuel injector o-rings (on the first tear down at least) but it’s not a bad idea too and they’re not usually expensive.

 

[Acrad]

Gasket instead of FIPG for repair

Vendor: J2HundyOutfitters - https://forum.ih8mud.com/members/j2hundyoutfitters.230864/
@J2HundyOutfitters

Contact

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1URFE/4.6 Valley Guard Seal

🛡️ 1URFE / 4.6 Valley Guard Seal For Lexus GX460 & LS460End the Leak. Reclaim Confidence. Drive On. Your Lexus 4.6L V8 was built for refinement, not regret — yet hidden deep in its engine valley lurks a design flaw that can sabotage it all. The factory heat exchanger cover sits atop two...

j2hundy.com

#CoolantValley #J2Hundy #Coolant #Valley #Gasket

 

[swild]

Gasket instead of FIPG for repair

1URFE/4.6 Valley Guard Seal

🛡️ 1URFE / 4.6 Valley Guard Seal For Lexus GX460 & LS460End the Leak. Reclaim Confidence. Drive On. Your Lexus 4.6L V8 was built for refinement, not regret — yet hidden deep in its engine valley lurks a design flaw that can sabotage it all. The factory heat exchanger cover sits atop two...

j2hundy.com

Take my money!

 

[Acrad]

Previous thread here including input from vendor

Post in thread 'J2Hundy Valley Plate Leak Guard Seal'

Feb 24, 2025

If any of you know me… “knowledge without experience, is just, information.” So let’s give it a shot and see what happens. Here’s about the 30th coolant heat exchanger re-seal I’ve done. I like doing this job, I find it pretty easy and satisfying. I even plan to offer this service as a mobile job, when I’m stateside.

Background: this particular 3UR came to me after having the coolant heat exchanger plate re-sealed with 1282b about 80k miles ago. I know the Toyota master mechanic that did the job. I highly doubt he did a poor job. So here we are, customer wants...

• Taco2Cruiser

• 

 

[Bang Bang]

Getting ready to do the coolant valley repair and just ordered this gasket. Thanks for that @Acrad . Always on top of stuff as usual.

 

[Rednexus]

Agreed, looks like a great part and kudos to the seller for thinking of the idea!

 

[Acrad]

I ordered a gasket.

Just shy of 96k miles.... and 3 coolant changes along the way.

In just last couple weeks or so I noticed the smallest amount of drop in my recovery tank. Topped off and noticed really small level drop.. maybe an ounce or so. Borescoped this morning and did find some pink crusties somewhere in the rear on passenger side. Not that it matters but I can't quite place where I am at but seems like fairly far back..or at least it seems that way.

Maybe someone can recognize more specific location from my pics. I've been staring at jmanscotch's pictures for a while now.

I need to see if I am missing any parts.. I bought everything along the way and added to my 460 parts bin as I figured this was going to happen to me at some point.

Some pics are just general are to help identify where I am.

 

[Acrad]

 

[Acrad]

 

[xychromosome]

It's just a matter of time. Your mileage lines up as well. Looking forward to hearing about your experience using this new gasket.