Aveo is toast, what happened? Mystery theatre.

[ckalous]

Sleuthing what caused piston failure >> no compression>>> oil in sparkplugs >>> engine is (likely)toast.

Brother in law driving his car. Overheats and coolant coming out of timing cover just a mile after leaving the house, he comes right back driving hot. He doesn't think he drove it hot for very long, but could be that he had driven it hot the day before without noticing because of the puddles on the ground showing it had been leaking the previous day, too, and he got in late night, tired, etc. Car never shut down on him as he drove back, and we started it a while after cooling to move it into my driveway.

So I do the timing belt, water pump kit. I've done several of these on several engines including DOHC Hondas. So I am not a pro, but I know the ins and outs of timing, tensioning, TDC, lining up teeth, marks, etc. Replaced coolant.

Car starts. Sounds like its running fine. Test drive with about a 10 mile drive up to 70mph. Performing dandy. Top off coolant. Voila. $170! High fives!

So he drives off a while later and after about 40 miles, loses all power. Dead. Calls me for help. Says it did not overheat, check engine light never came on. Starter is running, but sounds funny and nada from the engine.

I think, "damn it, what did I do wrong on the timing belt? Did it break already? No tension? Skipped? Didn't torque something correctly?" Feel bad that I probably destroyed his engine by screwing something up.

Got the car towed back. Starter is turning motor with no resistance (AKA no compression). Lots of Oil in at least two spark plugs.

BUT timing seems fine. All components in tact, timing marks line right up on all revolutions still. No damage i can see.

I have not done any compression tests. Will pull plugs and check compression in all four cylinders for good measure when I have a moment. Certainly at least one or two cylinders have no compression based on how easy it is to rotate the engine.

So trying to figure out what I'm missing about my timing job to learn something.

OR would heat damage occurring when it was run hot (maybe longer than we think) cause piston failure to sneak up a while later? And the timing has nothing to do with it?

Thanks. Checking out used engines on Ebay, but if I get one, I'll likely do the timing belt on the bench and want to make sure I know what I missed.

CK

[petrified.rabbit]

I am curious what part of overheating made you decide water pump is what went bad, and thus doing that and a timing belt?
Did you look at the water pump you took out? how is the impeller and bearing?

Check the oil for "frothing" or level. I would bet that the oil is high due to coolant being in it. The head gasket probably blew on cylinder 1 and behind the timing cover.

I am making some assumptions here about the timing, a common mistake on the pre09 engine is to be off one tooth. Just from how it goes together. It probably ran fine until he revved it up. I can't remember if the one tooth was enough to destroy valve, I do remember that it lost power at higher RPM. Although I suspect it was also probably running with a blown head gasket and overheated a second time as well. Unfortunately it seems like a compression test attempt might just do more damage at this point if it was a timing issue. If it is just the blown head gasket it would need to be pretty bad to just "free spin" with the starter.

[ckalous]

Thanks for the reply.

I did the water pump/timing because the leak was from behind the timing cover. Also, it was not blowing smoke and the oil, at least on the dipstick, seemed fine.

The waterpump that I pulled was still spinning but with resistance and catching. Much like other water pumps that I've pulled.

The leak was gone when we got it running again, and it didn't overheat so I figured that I had hit the mark.

Now it still is topped off with coolant and supposedly did not overheat when it died, so I am not sure the head gasket is the problem. And as you said, it spins too freely to just be that, anyway, so if the headgasket is the problem, its clearly cascaded into something worse. Some valves are at the very least bent.

Still seems like major engine damage. Likely caused by timing out of wack, but it sure looks line up properly no matter how many times I've spun it.

[2010AveoLT]

I would definitely put a borescope into the cylinders and look for any damage.


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