Coolant Leak - Bypass pipe O-ring

I had mystery leak and was finding coolant where the transmission and engine meet. Turns out it was a bypass pipe o-ring that connect to the back of the water pump.

Changing all the gaskets and o-rings just incase. Doing the water pump just because everything is out of the way. Timing belt was changed at 100k in 2013 @ 160k now (the belt came in the kit, might change also)


Anyways found this repair/ service
Manual online thought I’d share. For 2005-2006 Tundra
https://drive.google.com/file/d/0B-5MhfqaHsHObmt6RDVhOGtKWjA/view

 

Nice work doing it all while its open. Do you have a pic of the leaky O-ring Connection? We have a few members come through here with that same Coolant Symptom at the Engine/Tranny spot.

 

Below is a photo of what the leak looked like. It leaks here because the coolant leaks within the engine valley and the block has two holes on the back like a gutter.

Here is the video I found explaining it way better. https://www.youtube.com/watch?v=6fx5hFQHUKI

Below is a photo from under the car, where it was leaking. (Engine meets the trans)


Below is what the bypass pipe looks like, you can see little no O-ring left. This O-ring connects behind the water pump.


One thing I didn't do that I regret was not doing a pressure test before draining the coolant. This would have allowed me to see everywhere it was leaking because I had the head off. So now I am replacing every gasket and o-ring.


Will update you later this week since I am waiting on parts.

 

Thanks. I’m trying to remember, but I think that O-Ring (the small one which failed you) is suppose to be replaced during the Timing Belt Change. Trying to remember if I did mine? Maybe yours was skipped last time?

I remember 2 O-Rings large and a small.

 

Yes, those two O-rings come in the water pump/ timing kit. I don’t think they changed the back one (small bypass pipe) back in 2013.

 

Amazing how much work an o ring can cause. Good job finding and fixing that.

 

'02 Limited 2UZ-FE 189k.
Similar problem after completing a timing belt swap. What a pure joy to discover a leak as I was all done and about to reinstall the lower splash guards... Noticed the coolant overflow container level kept dropping...

Changed timing belt, water pump [

$167 AISIN TKT-021 Engine Timing Belt Kit with Water Pump, grey

AISIN TKT-021 kit], serpentine tensioner, Idler pulley, fan pulley bracket, accessory drive belt, coolant drain & fill, spark plugs - all new & OEM replaced.

Can't find P/Ns for this O-ring and [water neck(?)] thermostat housing O-ring. Anyone have the P/Ns or specs for these rings?

 

Can you add photos of what you need part numbers for ?

 

I'm assuming he's talking about the O-Rings that are included in the timing belt kit. Maybe implying that his ripped or weren't included in the kit he used and now all he needs is the O-Rings separate of the timing belt kit.
Just a guess.
This is the PN for the thermostat gasket that I used on mine. Amazon says it doesn't fit for whatever reason.

$10 Lexus 16346-50010, Engine Coolant Thermostat Gasket

16346-50010, Engine Coolant Thermostat Gasket

 

Thanks NickB_01TRD and bmf4069 for your responses.

I've copied the pic from OP showing the locations of the two o-rings I need. Small one for the bypass tube and larger one for the water neck.

BMF is spot-on about the two o-rings from the

$167 TKT-021 Engine Timing Belt Kit with Water Pump, grey

TKT-021 kit. Thanks for the link to the thermostat gasket but that's not what I need. Should be something easy to find, I'm just ridin' the struggle bus here...

Thanks in advance, I love the community resources here!

 

By george, I got It!

For anyone else looking:

Bypass Pipe O-Ring - 96761-24019
Water Neck O-Ring - 96761-35035

 

96761-35035 Engine Coolant Pipe O-Ring
$4.11

96761-24019 Engine Coolant Pipe O-Ring $3.83

part numbers I purchased

 

While I was in there I also replaced these coolant crossover seal/gaskets, there were two total in the front, there is also two in the rear (didn’t mess with those)

 

Thanks a ton Jerry!
I didn't tear that deeply into it as I was only doing timing belt / front of engine work. I'll def get those done if I need to pull the intake.
Looks like some sleep and a patient parts tech was what I needed.

 

Hey Jerry, might be a long shot but I have the same engine in my 03 4runner. Was wondering what part #s you used for those front bypass pipe gaskets?

 

@runna91 the ones in the picture below?

 

@jerryallday yes! Exact ones! I believe that’s where my coolant leak is currently. I attached a picture where some coolant has pooled up, a lot has pooled up under my intake manifold as well.

 

It looks like it might be the o-right that goes from the thermostat housing and connects to the bypass and it’s just pooling up there. Since it’s wet pretty high. In the photo shown.



Looking thru my emails, trying to find the part number for the bypass seals, Please double check with dealer
Gasket - Toyota (16341-50020)

 

@runna91 it looks like the Toyota Parts system lists a lot of T4R as using his part number, click on 'What This Fits' box here: https://parts.toyota.com/p/63047124/16341-50020.html

If you need help with the Toyota Parts system to confirm and order the parts, check this thread.

MAKE SURE YOU DON'T ORDER YOUR PARTS ON scAMAZON -or- fleaBAY!!!


Actually, here's a copy-paste of the T4R in the compatibility list:

​

 

@jerryallday thanks again! I will double check the part numbers. Also thanks @shifty` for all the good info! I’ll look into that thread.

 

You're welcome. Now hurry up and buy a 1st Gen Tundra, and hang out more