2007 Tribeca, need some opinions on engine durability

[mschn99]

So this is my first post, and I have never owned a Subaru.

 

A little background on me, im a Senior Master Tech with Ford. Ive never owned a Subaru but had a girlfriend that had one and always enjoyed that little car. We have a friend of a friend with this 2007 Tribeca that has a major headgasket failure on the engine (i believe they are all the same 3.0l). Car has approx 180k on it but appears to have otherwise been maintained well from what i can tell. Body is clean and interior shows normal wear from a grandmother of 4 but not major defects like tears in the seats or anything. Overall pretty clean looking car.

 

The engine obviously has a headgasket failure. It immediately pressurizes the cooling system when started and also runs rough (as well as cranks like it has a dead hole). Oil appears maybe just a little milky, but not really bad. I have no clue how hot it got when overheated or for sure how many times it got hot.

 

So my question is this from people that have experience with these little airplane motors when they dont have issues, what kind of life would be expected out of one (engine and trans) that did not see this overheat issue.

 

And then how durable is this particular engine when you see them get hot and how often do you see other issues when they get hot. I understand that this will just be opinions and nothing will be known for certain until after teardown, but if they are prone to hot spotting cylinders or scoring cylinders its not worth me buying. If for the most part this is seen and i just need to tear it down and machine the heads and put it back together with new gaskets, it would totally be worth picking up for my wife to run around town in, and for our occasional trips to the snow in the winter. If fixing it is going to involve a motor, it just really isnt worth putting the money in as this particular engine seems a little on the expensive side even for a used on for a vehicle thats probably only worth $4500 as it sits according to KBB.

 

All help is appreciated!! Thank you in advance.

[mschn99]

Also, i apologize if this isnt in the proper forum, i could not find a Tribeca one

[idosubaru]

If there's any oil/coolant mixing I wouldn't even think about fixing it.  Subaru's don't mix oil and coolant unless something odd happened - and suggests it may have been severely overheated multiple times. I would need very compelling evidence to put my time into repairing that engine. 

 

If the overheating doesn't seem significant it's worth a chance.  Installing a JDM engine is another option.

 

Those engines do 300,000 miles without blinking if they're not overheated/run out of oil.

The only thing they need is serepentine pulley bearings ever 60k or so (30 minutes and $20), super easy.

They'll need typical maintenance items like plugs, valve cover gaskets, and oil cooler gasket - all easy and I often just do them all at once to be done with it (and the plugs are easy to replace with covers removed)

 

They sometimes loose rod bearings after significant overheats, discerning how badly it was overheated is a good idea. 

 

That said - they're otherwise such robust engines it's worth a shot to repair if you're just itching for somethign along these lines.  But that engine is twice the work of a normal Subaru headgasket so it's a beastly job.

 

If you do replace the HG:
Use Subaru only or other verifiably robust headgasket

Resurface the heads

Resurfacing the block isn't even a bad idea but few people do that or are set up to do it.

[1 Lucky Texan]

run the suggested octane - probably premium (that's what I run in our 03 H6)

 

it can be tricky to 'burp' all the air out of the cooling system in Subarus, (helps to either fill the block thru the top hoses, or get the nose up in the air. Also, put a tiny clamp or a coupla small zip ties on the little overflow hose at the nipple on the radiator's 'neck) plus , they need a thermostat with a larger wax capsule - so, over time and multiple owners, the cooling systems get abused and an engine is overheated. Very rare to hear of someone rebuilding an H6, even the H4s rarely get their cases split it seems. Get an engine from a wreck - maybe JDM as said - that's a common swap when folks have overheated soob motors.

Edited October 27, 2016 by 1 Lucky Texan