Mirage 3A92 Engine repair in process. (Problem: low compression)

[AtomicPunk]

Doubtful as the goo in the heater core is blue not white.

I guess. Though I do seem to remember from chemistry class some substances change colors based on temperature. Most (if not all) the heater core replacements have happened d/t no heat output, not an overheating event. Just saying its a possibility. Or it could be completely unrelated. Were that my engine That failed at 34k miles, I'd like to know why.

[Eggman]

I guess. Though I do seem to remember from chemistry class some substances change colors based on temperature. Most (if not all) the heater core replacements have happened d/t no heat output, not an overheating event. Just saying its a possibility. Or it could be completely unrelated. Were that my engine That failed at 34k miles, I'd like to know why.

And who knows - maybe one thing causes the other? Can't tell from here.

[foama]

... Most (if not all) the heater core replacements have happened with no heat output, not an overheating event. I'd like to know why.

There is a separate thread on that!
Summarized:
With mostly 2014/2015 cars, heater core and coolant react to produce a gummy, sticky goo that clogs the core.
Prevention is to thoroughly flush the old coolant out and put the correct new coolant in the proper concentration back in before the core gets clogged.
If already affected, some have put diluted ammonia water (spirits of ammonia) into the core (not the engine!) overnight, and then force-flushed the core with a garden hose in both directions. Helps well and is cheap!
Others have replace the core ($$$!).

It pays to monitor PH of the coolant yearly. The PH should be around 8.5 Any change and the coolant is exhausted and should be replaced asap.

[AtomicPunk]

There is a separate thread on that!
Summarized:
With mostly 2014/2015 cars, heater core and coolant react to produce a gummy, sticky goo that clogs the core.
Prevention is to thoroughly flush the old coolant out and put the correct new coolant in the proper concentration back in before the core gets clogged.
If already affected, some have put diluted ammonia water (spirits of ammonia) into the core (not the engine!) overnight, and then force-flushed the core with a garden hose in both directions. Helps well and is cheap!
Others have replace the core ($$$!).

It pays to monitor PH of the coolant yearly. The PH should be around 8.5 Any change and the coolant is exhausted and should be replaced asap.

I'm familiar with the heater core/goo issue. My statement was "if my engine failed at 36,000 miles (like the thread originator), I'd want to know why." Maybe I didn't phrase it right. Regardless, I hope he can determine why his engine failed so early.

[foama]

I'm familiar with the heater core/goo issue. My statement was "if my engine failed at 36,000 miles (like the thread originator), I'd want to know why." Maybe I didn't phrase it right. Regardless, I hope he can determine why his engine failed so early.

Understood!

The white stuff might be residue from some sort of radiator repair sealant. If coolant were very low, the stuff would form on exposed surfaces. Could also explain why the engine went broke. Also, that stuff doesn't conduct heat well, another reason for not putting that crap into the coolant, and another reason for why it may have busted the engine.

[Fummins]

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So how’s this all work out for you. This was a great thread. Before the bickering…

[7milesout]

Agreed. This was / is an awesome thread. Dave's pictures were awesome. I'm glad he had the cojones to tear into this engine. I hope he gets it, or has gotten it all squared away.

I'm a little confused, or just don't know why he didn't go back with an original 3A92 piston so as not to have to make modifications to the Toyota one. I guess I have read that Mitsubishi parts are difficult and/or expensive to get. Maybe that's the reason.

But I would be a bit leary to machine down the crown of the piston (for cylinder clearance). I would be concerned thinning that piston material thickness might lead to problems (I only speculate, no expert here for sure). It would be nice if the wrist pin location in the piston could be modified ... but I cannot imagine that being possible ... at least without serious machine work (welding-machining), cost, and imperfections to that process leading to all kind of piston problems (piston rocking, etc).

Even if Dave had brand new perfect OEM parts to rebuild with, I'd also be concerned about the problem happening again.

The one thing I will say, that you guys have already pointed out - This does seems related to cold climates and over-rich to engine flooding issues. I think I'd run a block heater on these suckers if at all possible if I lived up yonder.

[Eggman]

Those block heaters work great in warmer climates too. The sooner the engine heats up the better. But would it stop this kind of damage? That’s a good question.

[7milesout]

Those block heaters work great in warmer climates too. The sooner the engine heats up the better. But would it stop this kind of damage? That’s a good question.

Right. I don't necessarily propose that it does stop the issue, because I have no idea. But it couldn't hurt.

[Christopher_B]

I wonder what would happen if all three pistons were replaced with toyota ones? Clearance issues with plugs and/or valves?