Timing chains whats your opinion

[ACEPA]

I have seen horror stories about short life GM timing chains on you tube not making 80,000 miles. My lacrosse passing 186,000 miles has the same timing chain. The only logic I can use for its longevity is I have always used Mobil 1 oil. What's your opinion?

 

[ulycyc]

GM does not have an exclusive on timing chain problems. All makes and models seem to have similar problems

 

[agaric]

I have always used Mobil 1 oil

You answered your own question.
Regular oil changes with the correct oil, hence the Dexos label oil for GM vehicles, are the answer.

 

[EDSELRANGER]

I think it's pretty much a crap shoot. I changed my oil right on schedule or early, and always used the Dexos Mobil 1 full synthetic. At approximately 125,000 miles I had to REPLACE the ENGINE. Dealer said valve dropped resulting in extensive piston/cylinder damage. They said they thought the damage happened as result of timing chain failure.

 

[richardnewton]

GM has upgraded the timing set for the 2.4 over the years.

I think the oil sprayer and main tensioner were changed, for example. Other part numbers were revised too.

With use, the chains stretch and the plastic guides become fragile.

So with your mileage, you might consider a new timing kit (assuming the car runs well). While at you, you might replace the otherwise difficult to reach water pump. And pull the plastic intake for a full cleaning of the pcv orifice/channels (or just replace the thing).

If you have the hybrid, the serpentine belt and tensioner should be changed. They were upgraded too.

The 2.4 was a very durable engine prior to ~2010 (I suspect changes to pcv and vvt changes were the problems but nobody really knows.)

 

[ACEPA]

GM has upgraded the timing set for the 2.4 over the years.

I think the oil sprayer and main tensioner were changed, for example. Other part numbers were revised too.

With use, the chains stretch and the plastic guides become fragile.

So with your mileage, you might consider a new timing kit (assuming the car runs well). While at you, you might replace the otherwise difficult to reach water pump. And pull the plastic intake for a full cleaning of the pcv orifice/channels (or just replace the thing).

If you have the hybrid, the serpentine belt and tensioner should be changed. They were upgraded too.

The 2.4 was a very durable engine prior to ~2010 (I suspect changes to pcv and vvt changes were the problems but nobody really knows.)

Good to know this !

 

[richardnewton]

Oh- I would like to add that there is an upper bolt that is especially prone to wear. That bolt is hidden behind an aluminum plate and holds one of the plastic guides.

Dorman has a fix for that bolt with a nice case study. I'm not 100% clear if this can be done on the car with the timing belt tensioned.

Timing Chain Guide Bolt Case Study - Dorman Products - Aftermarket Auto Parts & OE Solutions

This solution saves hours of labor and hundreds of dollars in replacement parts that would otherwise be required to remove the cylinder head to remove the old bolt

www.dormanproducts.com

I guess this guide/bolt and the top tensioner are the high wear parts. Maybe a streched chain is a driver. Or maybe driving with low oil is a driver.