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Thread: 2005 Chevy Classic - no idea what the problem is

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    2005 Chevy Classic - no idea what the problem is

    So, about a week ago, I drive home from work, and coming down the hill, I let off the gas, and hear a rat-a-tat sound, like the lifters knocking. Parked the car, and left it, since it was too dark to mess with. When I checked the oil in the morning, there was no oil on the dipstick. Ended up having to add 2+ quarts. (I know, opened the door for a mess of other issues). Well, after adding the oil, car started fine, and ran great, no odd noises. The one thing it did do at this point, is a little bit of a surge? when at a stop. It would kind of pulse; nothing major, and when moving it seemed like it was running perfectly. This morning, went out to go to work, started it up, and had the rat-a-tat noise again. Let it sit, running, for a minute, thinking it might need a second to get oil dispersed. Didn't get better, so I shut it off, and took my other car to work. Got home tonight, checked the oil, and it was in the proper range on the dipstick, no loss since I added last weekend. So, I get in, and try to start it. It turned over, ran really rough, I heard a "clump", and it died. Now, it just cranks, no attempt to actually turn over, though, like it's not getting fuel. Haven't looked at anything yet. I do have an OBD tool, and the only code I get is P0128, Thermostat - temperature too low for thermostat to control. However, I've had this code for quite a while. I hadn't done anything about it, because the car was running great.

    My thought for tomorrow is to rent a fuel pressure kit, but I don't know what kind of pressure I should have at the rail. Also, the "clump" sound really makes me nervous.

    I'm ok turning a wrench, but I've never had to do anything really to this ecotec, and they don't make a book for the Malibu Classic, so I don't have anything to look at on that end. Any ideas where I should start? Should I pull the top off the motor, to check the lifters/rods?

    Any help would be greatly appreciated.

    Thanks,

    Joe


    ***Small update*** - I do get some RPM when I'm cranking the key, so I'm hoping that means I don't have a piston that has bent, or somehow gotten stuck in a cylinder. I did see a Youtube video last night about a Pontiac that wouldn't start due to the temp sensor, so I'm thinking I'll replace that, since it's a pretty cheap, and accessible item. I don't think it's the main issue, but the only other thing that is coming to mind from reading different forum posts with the same type of issue would be the timing chain, and I really hope that's not it.
    Last edited by Tamvolan; 01-21-2017 at 01:50 PM.

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    So, I took off the valve cover today. As you can see here, inside_valve_cover.jpg, there's oil/water mixture by where you add the oil. However, looking down at the Cylinder 4 area, and throughout, there's no sign of that milk anywhere else. Cylinder_1.jpgCylinder_4.jpg. Looking at the timing chain, there is a very slight sag between the cam sprockets, but I don't know if that's a bad thing or not. Timing_chain.jpg

    Any advice is greatly appreciated.

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    I'm betting it jumped time

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    I'm betting it jumped time
    blackbirdracing Quoted Post
    So what's my next move? Is the motor done, or do I go further, taking off the timing chain cover, to look at the bottom? What am I looking for? Am I correct in my thinking that since I am getting some small RPM when cranking, that the pistons "should" be ok? I am not familiar with this motor, so any and all advice is greatly appreciated.

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    So, manually rolling the motor with a breaker bar on the camshaft bolt, I've confirmed that "something" has happened with the timing chain. While rolling the motor, the chain is taut between the cam sprockets. When #1 is at top, or bottom, the chain goes very slack. The pistons seem to be moving freely, it's not difficult to roll the camshaft. I'm guessing that the "rat-a-tat" sound I had been hearing was possibly the pistons hitting the valves?, and so the valves may be bent now?

    I guess the big question, that I hope to have some kind of response to, Is it worth going deeper? I know I can get a rebuilt head for around $300, does that include new valves, and all, typically? Is there a chance that there is damage to the tops of the pistons, as well?

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    If it cranks faster than normal, sounds as if the spark plugs are out, you need to replace timing chain and all guides. Running an Ecotec without enough oil is disastrous to timing components.
    Last edited by redline35; 02-08-2017 at 01:30 AM.

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    I wouldn't worry about piston damage. The more likely scenario is bent valves. A rebuilt head will have not necessarily NEW valves, but will have valves that have been ground and checked for proper sealing. The sound you're hearing is most likely the loose chain. A word of advice - if you replace the chain, guides and tensioner, don't install the tensioner in the activated state. And do NOT use red Loctite on the bolts that hold the guides in place. Red Loctite is permanent. Use blue Loctite instead. I believe it's Loctite 242. If you have questions and are on Facebook, look me up. Bob Johnson, retired at Caterpillar Inc. A friend request will be accepted and we can correspond via Facebook Messenger. I've learned a truckload about these engines the HARD way and am happy to help.
    Last edited by redline35; 02-08-2017 at 01:59 AM.

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