I was talking to a mechanic that I trust today, the topic of timing chain came up. He says that GM recommends new chain guides EVERY 70,000 MILES.

 

Wow I'm more than twice that!! running on borrowed time?

 

After reading about the failures others have had I can see that as good preventive maintenance considering the consequences, but that is relatively rare. Most of us get by just fine. Make sure you check out any excessive noise from that area and change the tensioner if needed, too much slack from a failed tensioner will pulverize those nylon guides pretty fast.

 

No offense to your mechanic or you, But......

I'd like to see the documented material that GM stated that. After all, we all know a "trusted" mechanic, including those who are employed by GM dealerships, that have made statements that were fictitious/personal opinion/back patting.

If GM "recommends" timing chain guide replacement as indicated, there would need to be a letter, TSB, etc. to support that.....just saying.

Oh, and I forgot the most important part....notices and/or addendum would be issued because this repair would be part of the 5 yr/100,000 mile warranty program involving required maintenance to comply.

Not saying that is not the case, I just haven't seen or found it.

 

I'd say that the language they (GM) use is something closer along the lines of inspect at 70k miles. That's how most vehicle service manuals are. I, personally, do a timing belt, tensioner, water pump, cam/crank seals, and a leak-down at 100k whether it needs it or not. If the motor is interference, you're looking at a lot of work after it breaks vs. before.

My wife likes to point out that we don't get anything for resale after 100k and I like to point out that I've only ever had one car that broke down after 100k.

 

When my HHR reached 100k miles, I started to check my oil for bits of metal or nylon (from the guides) after I changed the oil. Strained it! I haven't found any noticeable bits yet, but that doesn't mean there's no wear. So far, the timing chain doesn't "slap, clack, or clatter" to my ear. I parked my '92 Achieva at 99k miles, because it was making a heck of a racket (ready to destruct at anytime, and because a CV joint let go the same day I gave up on it). At 140k miles now, how much longer can I trust the HHR chain?

 

Its a chain.... will be fine.

 

Huh?

 

Just venting bout chains vs belts. The bigger issue in my opinion is the tensioner vs guides as if the tension doesnt do its job it will then have some slack that can damage the guides and cause pre mature failure.

Ive had countless engines with chains and some that dont have anything to create tension or guide the chain the slack was horrible (you could prob remove 1 link and still have some deflection) nut still did its job.

The way ecotechs route their chain it makes sense but unless your hearing a rattle are specific noise in that area. I would get a wooden dowel, car on jack stands, safely secured, have it running at idle, put the dowel on the cover, your ear on the other end and if you have a internal noise, its going to be very apperent. The biggest mistake people make is replacing one part. If your doing the job, do it right, get the kit and do it all same time.

 

At 140K, a piece of one of the plastic guides broke off and wedged itself between the crank sprocket and the chain. Luckily this only made the chain skip time by one tooth, but made for a frustrating diagnostic process until base timing was finally checked. Ended up replacing all timing related components as a precaution and all is well 70K later.