Unsubscribe any time. We don't sell/share your email.
Engine began making a chattering / slapping noise from the passenger side under the valve cover. The noise always occurred between 1500 and 2500 RPM, at high load conditions, i.e. accelerating from a stop.
Removal of the valve cover revealed a severely slack timing chain, a destroyed upper timing chain guide, and pieces of metal and nylon sitting in the cylinder head by the cam towers. Mind you, I've maintained this car since it was purchased new. Ive changed the oil more often than the computer "oil life" algorithm calls for, and Ive ALWAYS used dexos approved oil of the correct viscosity, checking twice a month and adding as necessary.
Quotes others received to repair this problem ranged from $1500 to $2000 from all the things I read online, and seeing how involved this job is, I am not surprised. Thankfully, this was something I was able to fix myself, barely. It was an intimidating job made possible for me only by the internet and a good ol' Haynes manual. I paid approximately $400 for parts and an inch/lb precision torque wrench I did not have.
Upon pulling the timing cover from the front of the engine, I found more chunks of broken timing chain guide, pulverized nylon, and metal shavings that had been circulating in the timing case for God knows how long. Otherwise, the engine was squeaky clean and free of deposits, as you'd expect from a well maintained engine with fewer than 70,000 miles on it. I maintain that this was NOT a maintenance related failure.
The upper timing chain guide, the steel one that sits between the cam phaser sprockets just under the valve cover was eaten almost completely through. Much more, and a piece of it about 10mm x 60mm would have been dislodged and released into the timing case. That would be more than enough to break teeth off a timing sprocket, make the chain jump teeth, or break a chain, causing valves to hit pistons. UNACCEPTABLE.
The job took me, with no lift, only a garage, basic hand tools, and a corded impact gun about 12 hours to complete, my entire weekend. This is NOT something that was caused by neglect or abuse on my part. This is very clearly a fatal design flaw. One timing guide has a weak point. The story is the same for all these engines. It breaks, the timing chain goes slack, and begins destroying the rest of the timing components as it knocks around. If left unchecked, this can cause engine destruction, as this IS an interference engine.
This chronic problem is well documented among GMs 2.0, 2.2, and 2.4 engines; the entire eco tec line. It is something GM should be fixing out of their pocket.
I've had many vehicles with overhead cam engines and timing chains over the years, and I've never had to replace timing components on any of them. This is an item that, when designed well and maintained properly, should have NO PROBLEM lasting the life of the vehicle. Timing set failure at 70,000 miles is an absolute joke! Otherwise, why not just use a belt!? Belts are supposed to have a maintenance interval. Chains are not!
Also, I'll work my ass off in the garage for a whole weekend before GM's service departments get any more money from me. This car has been a complete disaster. I can't recommend an eco tec equipped GM product to anyone, which is a shame, because these have the potential to be a very robust engine. If GM would revise one plastic timing chain guide and make it from tougher composite, these engines would be fantastic. I had a 2004 Malibu 2.2l go 240,000 miles and still run great. It was the body and suspension wearing out that did the car in. GM, you owe it to your customers to fix this at reduced or no cost.
- Doug B.,