Coolant leaking at heater pipe, at engine block

It’s leaking here?



what’s the miles?

 

I could have sworn those hose nipples are in the cylinder head, not the block.

I still think I'm right about that ... but I've looked in the 2010 repair manual (the PDF floating around, which might not be complete) and not found anything about removing or installing those nipples. (I think in other generations I did see some instructions like that in the manual ... I think the nipples got pressed in.)

There are instructions for installing the spark plug tubes, but not for those nipples, that I can find. That would lend support to the idea that Toyota sells the cylinder head with those nipples already in place, and doesn't sell them separately.

But maybe someone will chime in who has had a head sent out for machining.

 

Yes:

From this ad:
Zylinderkopf für Toyota Prius W3 1,8 Hybrid 2ZR-FXE 2ZR 2211727262 | eBay

 

Could involve buying a cylinder head. Bit pricey.

Maybe could involve buying a cheap trashed cylinder head with a good hose nipple and trying to transplant that. But if Toyota isn't selling the nipples separately, that might be a hint that getting them removed from the head or installed in it could be something easier in the factory than in the field.

 

salvage cylinder head?

 

As a machinist, it would not me hard to make a nipple which might even be better than OEM.

 

I think you'd want to be REAL sure, it's not just seeping from the hose. It's the braided one, right?

I don't think you've mentioned the miles?

 

Cut the tube flush with head, internally thread the tube, install threaded replacement.

The threaded replacement will slightly expand the tube and seal the leak.

 

With the proviso that I didn't design the head or cooling system, this is an arms length/shade tree/bush fix/field repair, YMMV, etc...

Primary risk in this approach: the head is so thin at the point the tube is press-fit into the head that the existing and replacement tube threaded lengths are marginal, an insufficient number of mating threads, and won't provide much lateral load bearing strength. Won't know until measuring the existing configuration.

If the above looks riskable/doable, I would thread a piece of slightly (1/8" or 3mm OD) oversized aluminum pipe.

With a micrometer, measure the internal diameter ** and depth ** of the existing tube where it enters the head.

Choose a replacement aluminum pipe whose external diameter is slightly (1/8" or 3mm) larger than the above internal measurement, and whose length is as the existing tube external length ** plus the depth of the existing tube into the head **.

Internally fine tap the existing tube just short of the depth of the internal depth.

(Take care to try to capture debris from the threading process. It is working in coolant, not oil, so not an existential concern.

May also want to try to slightly recess the tube where it enters the head with a 45 or 60 degree chamfer to allow for tighter sealing at the head face.)

Externally fine thread the new pipe to match the above internal thread and say 1/8" shorter depth so as to leave a shoulder that seals to the head

Reassemble with Teflon pipe tape.

Pieces of pipe are available at a good hardware store, plumbing supply store, maybe HD or Lowes.

Leak test results.

Don't quote me...

 

* head

 

I have done similar modifications with the sports car, but never this particular work, and not on a Prius head.

 

Exactly . Gotta have tools ask machine shop employee who breaks down the parts for tanking .I thot they o ringed and pressed in . If you go in tube with angled pick can you feel a ring land in the tube portion in the head??? That's the sealing o ring that inserts in head around that barb at pressing in time