My brother has a 2012 malibu and it started acting up. I would call it a misfire condition, no code was triggered though. Research indicated a worn timing chain guide or tensioner so I bought a kit and ripped the engine apart. As I dug into it I noticed some thing like the heat sheild on the wires just fell apart in some areas. The plugs and coil packs were barley hand tightened. Which he paid a garage to do 5 days ago. The plugs didn't look new and weren't gapped right. They were ashy and grimy with old dialectric dried on the side.

When i remove the front cover i heard something fall. It was peices of the fixed position timing chain guide "letter E in the pic" the whole bottom half was broken off and the chain was rubbing the bolt that holds it in place. Mangled the bolt. The tensioner on the other side I can compress with my pinkie.

surprising the engine seems fine. I dont see any scoring or indicators of blowby inside cylinders. Compression felt fine when i was setting top dead center. The main worry is the grayish film I see everywhere.

I'm wondering should I just go grab an engine from pick n pull or just throw the kit in this. what test can i do with the engine 1/2 apart to verify condition? And where could I get that bolt if I do decide to keep the engine?

Appreciate any suggestions.

 

I think it best to repair the engine. These days Pick and Pulls are loaded with people who want to sell what they ****** there. I put an entire A/C system in my girlfriend's Mustang using P&P, but that was many, many years ago.

Your brother likely got ripped off by some shade-tree "mechanic". Back in the day, most plugs were gapped correctly, but not these days. And finger-tight plugs were just plain wrong. If you need a solid brand timing chain, I'd buy a Cloyes chain as they are rock solid as they come for many decades now. I cannot tell you where to get the bolt, but I'd check online. There has to be a replacement. I'd call the Automotive Repair Bureau on this person as well. Put his **** on YELP too. People like this jerk make good technicians look bad.

 

the pick and pull here is pretty good. They use to go through the cars and take whats good but some years ago they made a policy to not do that. This engine seems simple enough but I'm not familiar with it. We got the chain and rebuild from a dealer because I needed to do the job quickly. I appreciate the recommendation. I was wondering if there is any common flaws with the engine.

 

The 2.4 is a good, decent motor. I like my 2015 Malibu 2.5 liter better, but a 2.4 is similar to the 2.2-liter motor in my previously owned Chevy Cavalier. My Bu' has much more power and gas mileage is much better than a 2.2 liter.

 

Honestly, they aren't great engines. Small cars are not GM's strong suite, and they may eventually get out of that market completely. I don't think it's worth replacing the engine. (especially as general fit & finish isn't great)
Since these are 11+ year engines, you're going to see a lot of wear & tear based failures simply due to high mileage.

As you found out, timing chains have a high rate of jumping teeth due to poor tensioners. This being an interference engine, that can lead to complete, catastrophic engine failure.

Piston rings are also weakness, and the engines starts to consume a lot of oil. This problem was well known by GM. Take advantage of the warranty extension they issued (if that's still possible).

Carbon buildup is an issue with most direct injection engines. This Ecotec is no exception. Valves and ports get caked in deposits, robbing power and causing poor idle, hesitation and even misfires.

If you are religious about maintenance, it is still possible to reach the 200k .

 

The spray intake valve cleaners work well. I not only used it on my 15' Bu', but my 98' K-1500. Man, that thing blew some serious black smoke out on my Chevy pickup truck. She still passed the Smog test easily as all hell like she always does. GMT-400s are great!

 

I replaced the timing chain and balance chain. Everything runs fine but I'm throwing error codes. All the same codes even after doing a factory reset. Car actually gets better gas then ever. Has a little vibration after restarting but that all. Timing marks all lined up. And balance marks were all on point. I aligned it to TDC on the exhaust stroke as specified in repair manuals. I've been looking online. Idk what it could be. I do have a decent computer when I get the chance I'll look at live data. Could it be a sensor?