Third Gen Coolant Bypass Pipe Fix

I wanted to share my fix for the plastic Coolant Bypass Joint/pipe that is common to fail on the third gen tacomas. I came up with a different fix, because the plastic tube failed at 65k and I'm not one to leave things stock if there is an obvious design flaw. Aka. I'm not doing this again at 130k miles. Kudos to all the other threads that mentioned the Lexus pipe, otherwise I wouldn't have known there was something close that would work with "some" modification.


1. Start with the aluminum Lexus Pipe PN: 16356-31080 and upgraded gaskets PN: 16341-31030 Qty: 2
2. Pull large and small tubes out
3. Drill & Tap large tube location for 1/2npt
4. Drill & Tap small tube location for m10 x 1.0
5. Plug 1/2npt with 90 degree brass fitting below. Angle the fitting so that it pointed slightly towards the middle of the engine. (Use red loctite or epoxy)
6. Plug the m10x 1.0 hole with a blanking plug similar to the picture below.(Use red loctite or epoxy)
7. Installed the 5/8 barbed fitting after the pipe was installed on truck (makes routing the pipe through the top of the engine easier)

Installation took about 6 hours, and I got to the pipe from the top of the engine. Removed the upper intake and removed the transmission mount to jack the transmission up so the engine would rotate away from the firewall.

Note: the only other difference between the Lexus and toyota part is the aluminum tabs and the big chunk on the right. I cut them off and relocated them, but that step isn't necessary. Those tabs are for a wiring harness, and you can just zip tie the harness back in place.

 

Hell yeah that looks good! Do you have a pic of the finished component before you installed it?

did the pipe on my 2016 a few years ago at 80k. Just did 120k service this weekend at home and the coolant expansion tank was at the “low” level. Too scared to look at that dreaded pipe again.

 

Added.

Please let me know if I missed any details.

 

good write up !! let us know how it goes as the miles go by .

 

Will be replacing mine eventually. Your modifications seem easy enough I may have to copy this. Hoping it holds up better than the plastic.

 

on the final product looks like you cut off or ground off excess aluminum protrusions on the right side to clean up the final product. I was wondering about the hole on the right side that does't appear to be closed or tapped.

 

I did remove the excess material, but that was just a preference.

The hole on the right is for a temperature sensor, which you can reuse the one currently on the truck. It's just held in place by a wire clip.

 

Any concerns with the brass being effected by the lower pH of the coolant?

I wonder if stainless would be a better option. Thanks for the write up I have been dreading doing this and putting a plastic part back on but this is a great option!

Thanks again!

 

Looks good! I’m not very familiar with that part, what did you do with the inlet shown here?

 

Thats

this is a location of the coolant temp sensor. Suppose to move one from the old assembly

 

Ford have a plastic tstat housing on the 4.0sohc ranger / explorer, with 2 push in temp sensors similar to this...
Everytime someone just swaps them over without replacing them as you can just service the rubber oring, no oem part for oring only.
Ends up leaking every time...
Install a new sensor, especially if its challenging to get to,

Some guys tried using generic orings without success.

Not worth the risk...

 

Very cool fix!

Thanks for sharing!

 

@ScaryVersion I was originally trying to use all aluminum fittings, but the brass had lower profile ones that help save space. Most coolant sensor fittings, and freeze plugs are brass so I am not concerned.

 

Just another question- did you relocate the harness mount you cut off by gluing it onto the left side rib of the pipe? If so, with epoxy?

This thread needs to be a sticky!! Great job, Billy!

 

@OnHartung'sRoad Yes sir, I used high temp epoxy. However you could also just use zip ties.

 

I would not know. I successfully avoided Ford products all my life and mcgyvering critical system of the engine in my cars

 

Is the metal part missing the groove for the O rings? The plastic part appears to have a grooves for an O ring.

Did you have any troubles getting it to seal?

 

im just trying to point out, reusing that sensor if its old, or even if its not old, may result in the sensor leaking due to the ring is compressed.
Principal is the same, regardless ford or toyota...