Reviving a 270K mile Highlander Hybrid

[Drifter]

Still waiting to reach a resolution with the junkyard. On Saturday it was "Call Monday when so & so is in." This morning (Monday) it was, "let me check and and get back to you in a bit." This afternoon it was "Yeah sorry we're still looking for it, we'll call you by end of day" ("it" being the 90,000 mile engine from the car reported salvaged 5 years ago). Of course no call yet.

Tomorrow I'll start losing the friendly happy go lucky demeanor and ratchet up the assertiveness. I hate conflict, but this car is actually for my sister and I find it a bit easier to spar on someone else's behalf.

On the plus side, a package I ordered when I planned on just doing the head gasket came in today:


I find complicated/overwhelming new tasks much easier with a proper factory manual. And the good news: if we do replace just the head gasket, the engine block does not need to leave the car as I feared in the original post. Highlander hybrid head gasket replacement is still a major project with 61 numbered steps and several more nested sub steps (and that doesn't include add-on maintenance like plug/thermostat/water plate/waterpump/timing belt/idler/tensioner/cam seals/crank seal replacement).

Most of those 61 steps are just tedious work removing familiar components to gain access to the heads (e.g. "remove front suspension brace" - aka the strut tower bar), but removing the inverter/converter will be new to me. Those specific instructions are further detailed in a section in Volume 1a with 25 numbered steps of its own (plus several more nested sub steps).

All in all replacing head gaskets seem like a doable challenge for anyone organized & methodical (with the space & tools). I'm leaning back towards the new headgakset route should we not find a low mileage used engine.

On that note, 6 local yards currently have hybrid-compatible 3MZ-FEs, but only 3 others claimed to be under 125,000 miles:
The claimed 103,000 mile engine was associated with a VIN salvaged with 180,000 miles in 2021.
The claimed 105,000 mile engine was associated with a VIN last sold with 123,000 miles in 2019 (and salvaged in 2021 with unreported mileage in a state 1500 miles away from the last sale).
And the claimed 125,000 mile engine had a VIN with 210,000 miles last reported salvaged in 2021.

So basically 100% of the claimed low-ish mile engines from 4 different salvage yards were lies. Guess I need to be a lot more skeptical of this industry...


Looking over the full engine rebuild steps, they are almost identical to the Supra & MR2 engines I've done. The biggest difference is Toyota doesn't allow boring and just says to toss the block when excessively worn. The aftermarket does make sleeves, but I can find no good reviews which makes sense with junkyard engines as cheap & plentiful as they've been and factory engines lasting so long.
On the plus side? the factory max spec for ring tolerance is pretty generous. Toyota is a lot more particular about the valves & valve guides ("bushes" in Toyota vernacular). It seems likely that a proper rebuild would end up replacing bushes, which I'd probably outsource to the machine shop. At that point they might as well do a valve job and then the project starts to snowball away from a cheap 5 year commuter...

[Piotrsko]

If there's a bit of a lip at the top, sleeves for the cylinders are just fine, particularly if you can tailor the metals for anti corrosion at the block to coolant junction.
Also used to work on odd ball engine restoration where blocks weren't available
Done all the time on old style big block diesels where you reman the engine with it sitting in the frame in the yard parking lot

[mpgmike]

I dug out the tools for the thread insert kit we used on the Rav4 and it's Time Sert.

[cRiPpLe_rOoStEr]

Originally Posted by Drifter

So basically 100% of the claimed low-ish mile engines from 4 different salvage yards were lies. Guess I need to be a lot more skeptical of this industry...

I don't know how bad it is there, but in my country it's quite common to see parts of stolen cars for sale at wrreckyards, and even with engine block numbers tampered.

[Drifter]

So the junkyard reluctantly issued a full refund because they could find no other engine with (documented) <150,000 miles. Magically they think the found the 70K or 90K engine I was supposed to get, but somehow its riveted-on vin plate got drilled out when their parts puller yanked it out of the car. Hmm...

None of the other yards had any engines with <150,000 miles so I decided to proceed with a presumed head gasket replacement on this one. I think it is likely this engine will have been warped and will need to be replaced, but by the time I get the heads off it won't be much worse to just yank the engine myself rather than pay a shop $2,000 to install a 150,000 mile old engine...

But after 2 afternoons I still have yet to pull even the front head. I am being methodical because it is my first time going this deep into a hybrid and because the factory service manuals, thorough as they are, still require some familiarity with the car.

Question of the night - how do I get this off? It looks like a perfectly round, probably plastic, nut on a probably plastic stud:


It holds down the injector/coil wire harness. It is tiny - for perspective the head of the bolts holding down each coil is 10mm:

(Among other things, I've ordered new coil plug wiring clips)


This water pump has not been leaking for long:



Wasted a lot of time trying to figure out how to unclip the 90-degree high voltage hybrid clips. They're old and brittle, but still required decent force to get past ~45 degrees... Injector clips were likewise more difficult than I expected. The coil clips were already broken so bonus I guess?

Finding the coolant drain cock on the back of the block also wasted quite a bit of time, but would have been super easy to spot if it was on a lift. Now that I know where it is, I could do it again in 1 minute, but that goes for pretty much everything I've crossed off the list so far.

The worst was the fuel relay, which you unplug to idle the car out of fuel (pressure). The manual showed it being in the relay box on the driver's fender along with cryptic instructions, but the "relay and fuse" box located there clearly wasn't right.


Neither were the other 2 fuse boxes on the passenger fender. Or the fuse box under the dash. Consulting the 3 relevant volumes did not help. Finally I realized the cryptic instructions meant to lift the fuse and relay box off the bracket and expose another relay box below:

The other head-banging delay was the upper intake manifold ("surge tank" in Toyota lingo), which despite being lightweight plastic requires not 1, not 2, but 3 metal braces - 2 of which require wrenching by feel because they're right up against the firewall.


Nothing earth shattering - normal shade tree gripes about access combined with a little added hybrid complexity. Unfortunately from what I see so far, I think there is less than a 50% chance I'll be able to use this engine. But we'll know more when I (finally) get the heads off and see if anything warped.



The good news is that I've seen no rust at all (well, aside from a seized heat shield nut currently marinading in PB blaster) and the inverter also looks to have been replaced with a new unit fairly recently. I don't like the look of one of the lower control arm bushings and, I think it is not sold independently of the arm, but that's not a huge deal. So onward we go...

[Piotrsko]

Dumb question now you are involved in disassembly.... why not do a pressure differential test to see if a cylinder is actually leaking and where?

[Drifter]

Originally Posted by Piotrsko

Dumb question now you are involved in disassembly.... why not do a pressure differential test to see if a cylinder is actually leaking and where?

Not a dumb question. A compression or leakdown test would be how you'd typically diagnose a blown head gasket and these days even shade tree mechanics often use borescopes.

When I got the car, the owner said that he took it to two different mechanics and they both diagnosed a blown head gasket. I talked to one of those mechanics personally and confirmed that was his diagnosis. He also said the engine was not overheating, just loosing coolant (which gives me a sliver of hope it won't be warped).

I have personally diagnosed the valve cover gaskets as bad as well as the valve stem seals. It also needs a new waterpump gasket. And there is a metal plate between the heads that seals coolant with form-in-place gasket that needs to be resealed. It is possible to do all that work with the heads still on, but much easier to do valve stem seals on the bench. And since the timing belt & valve covers will be off, pulling the head at that point is only a little more work.

There is still a small chance the head gaskets aren't blown. The waterpump and upper water plate leaks explain the coolant loss and the bad valve stem seals and valve cover gaskets might explain the rough cold start (oil seeps into the cylinder overnight around the valve stem seals and seeps on top of the spark plug by passing through the valve cover's coil seals). But at this point I think it is more likely that I'll discover the engine isn't worth fixing because I doubt an engine that leaked this much coolant never ran low & overheated.

Junkyard engines are cheap and plentiful here as long as you don't mind 150-250,000 miles. But I have a mental hangup about paying a shop $2,000 in labor to install a $500 engine that might not be much good. I certainly don't want to pay $7,000 for them to install a rebuilt engine ($5,000 engine, $2,000 labor) into a car that isn't worth $10,000 even in today's crazy market.

I didn't feel comfortable pulling the engine myself, but also knew I'd become more comfortable with that idea if I became more familiar with the hybrid system after pulling the heads. And that is the case. The hybrid system really isn't that bad - I think the book time to remove & replace the hybrid engine is 22 hours vs 20 hours for the non hybrid V6 highlander.

[Piotrsko]

Coolant leaks just mean coolant is escaping somewhere. My son had a toyota with a blown head gasket, which he repaired but it was still consuming coolant and blowing it out the tailpipe. He had a cracked intake manifold

[ksa8907]

Head gasket failure typically gets bad fast as the uncontained pressures wear down the rest of the gasket, the head, the block, etc. 8k miles on a blown gasket? Sounds strange to me.

[Drifter]

The water pump was definitely responsible for the external coolant leak, but I don't know how much (if any) damage was done from the owner continuing to drive with it leaking:





Or maybe the head gasket preexisted the water pump leak and the blue devil head gasket sealer caused the water pump to fail...