Diagnosing and Fixing a 2002 Montero 3.5L V6 SOHC that might be seized up

[nwoods]

Yeah.. that's bad. ... Any obvious leaks?

Several. I got the head off on one side, and it looks like the rear most cylinder was leaking pretty good through the head gasket. More troubling, small shavings of metal in the front two cylinders, and one of the spark plugs was cracked. One of the NEW spark plugs..... Valves look they are okay and well seated, but I'm not really sure what I'm looking at. Can't figure out how to get the driver's side cylinder head off. All the bolts are out, I can pry it up, but something in the back in hanging on tenaciously and I can't feel anything other than the coolant pipe, which is only attached to the head, I think. Nothing holding the head to the block, but it's not coming out. Photos posted below:

left bank with head removed, gasket in place:

Bottom of head. One spark plug removed.

Metal shavings and debris in Cylinder 1

Rear cylinder. You can see the oil leaking through the gasket. Check out the starter in the background, it's absolutely coated in oil

 

[nwoods]

I'm so annoyed at the previous mechanic. They glued everything together instead of relying on gaskets and bolts. I can't get the water pump off, had to take the entire coolant piping assembly out as one piece.

See the goo?

 

[coffeegoat]

Those shavings look funny to me. They look like aluminum, which makes me think they're from the head not the block/cylinder/etc. I also don't see any major scoring on the front two cylinders which is good. I wonder if they chased the spark plug threads and got some crap in the cylinder, though I would expect it to be gone by the time you saw it. I wouldn't expect oil on the heads, coolant yes, but not oil. Sounds like a botched head gasket job

For the driver side head, if you're sure you got all of the miscellaneous coolant bolts (I saw at least one you got,) and all the head bolts, and all the other crap on the back of the head, it's probably just caught on the alignment dowels. There should be one in the front and the back and it won't let you lever it off from the front. If it's a little sticky you'll need to lever the back up to break it loose and then it should just lift off (it's heavy too).

There are a couple joints that used gasket maker on, but there were for specific reasons - like a high likelihood of leaks. It is a pain to deal with though.

I see you got a breaker for the timing gear bolt, any luck on that yet?

 

[nwoods]

Those shavings are responsive to a magnet, so....

Crank bolt: Yes! I was able to remove it. I had bought a tool on Amazon, but it didn’t work/fit, so I just tried turning the crank bolt against itself, using the friction of the seized motor and a breaker bar. Worked fine. I threaded the bolt back in once the balancer was off and used an O2 sensor socket as a spacer and it’s narrow enough not to interfere with the locator pin. I can still rotate the engine a few degrees each way.

Next step I guess is to remove the sensor and coolant pipe from back of head and see if that frees up the head. It shouldn’t, but nothing else is visible.

 

[offthepath]

I think I'd pull the whole engine out. No sense trying to pull it apart one piece at a time in the car. It's clear the engine is FUBARd. Yank it and use it as a core for a reman. 2 days work and it would be up and running again.

 

[nwoods]

That’s clearly the end goal, meanwhile I’m learning a lot along the way. Also, I think I’ll need to reuse these parts on the replacement motor.

I’m still a bit fuzzy on how/where to buy a replacement engine. Pulling one from a junk yard really sounds like challenging, uncomfortable, difficult, hard work that i’d probably pay to avoid. I don’t mind tinkering around in my driveway, but a hot, oil drenched junk yard is hardly my idea of a good time.

I’ve found used, 100,000 mile engines on Car-Part.com, but not seen any sources of a remanufactored engine. Suggestions?

 

[coffeegoat]

Well, could be that magnetic aluminum -

Somebody did a remanufactured engine on the board, I can't remember who.... It was ~1.5 years back though.

 

[offthepath]

That’s clearly the end goal, meanwhile I’m learning a lot along the way. Also, I think I’ll need to reuse these parts on the replacement motor.

I’m still a bit fuzzy on how/where to buy a replacement engine. Pulling one from a junk yard really sounds like challenging, uncomfortable, difficult, hard work that i’d probably pay to avoid. I don’t mind tinkering around in my driveway, but a hot, oil drenched junk yard is hardly my idea of a good time.

I’ve found used, 100,000 mile engines on Car-Part.com, but not seen any sources of a remanufactored engine. Suggestions?

Nothing wrong with that, but you and your back will be much happier working on the engine out of the vehicle. Trust me.

Lots of places sell rebuilt engines. Just do some searching and research on the company. Here is one from JEGS for a montero...
https://www.jegs.com/p/ATK-Engines/...=4294829733&year=4294829859&productId=5436744

here is another......
http://store.rydellpowertrain.com/3...-6g75-Eng-Crnk-Snr-Mnt-To-OP--Awd_p_3543.html

I'm sure Jasper sells engines for a montero too.

 

[nwoods]

Holy Mary Mother of Moola, those Reman engines are expensive! That junkyard approach is looking better and better.....

 

[nwoods]

Ok, new (used) engine being shipped to my door. Means I have to pull this baby out this weekend. Do I disconnect the tranny from the engine while in car? I assume I need to drain the tranny?

Any advice on how to reach all the bolts around the bell housing? I’m not certain of I need to remove the cross member under the drain pan. It might help with access, but then I’ve got to rig up jack stands or something to hold up the tranny?

 

[Salonika]

EDIT: just realized you have a Gen-3.....so not sure what applies here. Good luck anyway.

I didn’t do anything to tranny when I pulled mine. Maybe when you put it back in you might have a jack on tranny for alignment but it supports itself if I recall.
There were a couple of the bell housing bolts that I had to do using like 4’ of extensions, laying on my back under the rig with feet pointing forward. It was tedious but it all worked out. The difficult ones were on the passenger side if I remember.....something was in the way but don’t remember what. Starter? Maybe it was the exhaust, I tried doing it without pulling the catalytic converters but in the end I think I dropped the front half of the exhaust for access. You don’t need to remove cross member or drain tranny. Just remember two thing: #1, pay attention to where the wiring harness for starter lies. It’s easy to misroute it over the EGR pipe. Enough EGR recirculating will melt right through, which would probably lead to some bad *******. Second, when you put the torque converter back on the tranny, make sure it is fully seated by rotating it. You won’t know it visually, but you’ll end up looking for psychological help when you cannot figure out why you can’t pull the bell housing tight. I f’d around with that for 2 days before a neighbor came by, reached in and rotated the converter, and it slid in another 1/2 ». He then said « don’t you know, you always gotta spin it a little ». No, I didn’t know. But I’ll never forget now.

 

[nwoods]

Well, I determined that getting the drivers side Cylinder head off would make it easier to access the tranny bell housing bolts, so I spent way, way too many hours trying to get that off. Finally did. The obstacle turned out to be pretty darn silly, I did not remove the bracket holding the transmission oil dipstick up. Doh!

Anyway, finally got that off and removed the heads. Cylinder 4 looks bad. Really bad...

I put that down and went back to look at the block. Holy Moly! I think I found the problem. I mean, there's supposed to be a piston in there somewhere, right? LOL

 

[Salonika]

You should be ok. You have 5 good pistons still.

 

[coffeegoat]

Uh where did it go?

 

[offthepath]

wow!