GEN1 V6 Engine failures

[chadzeilenga]

I’ve done some research here and on 4x4Wire and can’t seem to find any specific info on the failure mode of the 6G72 3.0 V6 engine.

I have come across a number of GEN1’s recently that are in decent condition but have a failed engine. Is there a weak spot in this engine that leads to this failure? I’m aware of the lifter tick issue, but is this an indicator of a coming failure down the road?


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[Toasty]

They are near indestructible, you need to treat it really bad to make it fail. Like overheat it really bad and keep forcing it to run with milkshake oil. Or more commonly rebuild it improperly, those motors are about idiot proof unfortunately we've made better idiots in recent years.

The trick used to be buying Monteros with a failed 12v 3.0, towing it home and putting a new timing belt on it. Viola! Good cheap trucks! I've had a few friends get them with trashed bottom ends though which is a real bummer. They do have the crank bolt issue all 6G engines have but it's usually fixable

 

[chadzeilenga]

Hey Toasty,
Thanks for the reply. I figured that these engines were pretty tough like the rest of the vehicle, but with so many recent ones needing engines I was starting to get worried about mine with 200k on it. Luckily the timing belt, crank bolt and HG were done by previous owner so I should be good there...

 

[1morebike]

I had one. The timing belt broke it...no big deal slapped a new one on and kept going. The head gasket blew and I decided that with kid some anti lock brakes and airbags would be a good idea so I bought a gen 3. I sold my gen 1 to some guys who pulled it apart and rebuilt it. I see it driving around town and really miss it. Mine had 300,000 on it. It was on it's second motor but the original 5 sp transmission that was smooth as could be.

 

[mudraider]

The biggest thing lately on the Mitsubishi Monteros USA Facebook page has been temps running hot. Probably be a great idea to get your radiator rodded, get out the 25+ year old gunk that is almost assuredly built up in places on your radiator. And I did say get yours rodded, not replace it with some aluminum and plastic one.

Hey Toasty,
Thanks for the reply. I figured that these engines were pretty tough like the rest of the vehicle, but with so many recent ones needing engines I was starting to get worried about mine with 200k on it. Luckily the timing belt, crank bolt and HG were done by previous owner so I should be good there...

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[chadzeilenga]

The biggest thing lately on the Mitsubishi Monteros USA Facebook page has been temps running hot. Probably be a great idea to get your radiator rodded, get out the 25+ year old gunk that is almost assuredly built up in places on your radiator. And I did say get yours rodded, not replace it with some aluminum and plastic one.

Hey Mud, I'm running a freshly rodded OEM radiator and after I installed is when all of this coolant rust started to get significantly worse. I thought it might be due to the additional coolant flow with the original radiator flushing out some debris. My post on coolant rust shares the failures encountered this weekend by backflushing that rust out of the radiator and then overheating on Sat night.

Since Saturday I've just been reading as much as I can on the 6G72 engine to put a plan together on what to diagnose while I have it together. I think my valvetrain got noisy from the heat (making a lot of noise at startup and doesn't quiet down). My hope is that the damage was contained to just the heads so I can get by with a HG change

So far my plan is:
- Pull all plugs and check for presence of coolant
- Compression check on all cylinders

With a noisy valve train, I'm not sure how I can diagnose damage deeper in the engine like a rod knock. I guess I'll get a look at the cyl walls once I get the heads off.

 

[mudraider]

Ninjaperformance.com sells lifters with the larger oiling holes, really quieted mine down. One of the guys runs an online filter on the throttle body water hoses, got it off Amazon if'n I remember right. Also sounds like they didnt get it all rinsed out if that's all from a freshly rodded radiator. Sorry that happened to you.

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