Colorado/Canyon Insight

[BuffettTruck]

So my wife and I are thinking of helping our daughter get her first used vehicle (she starts driving in a few months). She's a bit of a fan of the Colorado/Canyon. I am considering looking at pre-2010 models. Are there any issues with these early Colorados/Canyons I should be aware of?

 

[mrrsm]

Be Careful What You Wish For... Every Single Frame of the Video in Post #1 says it all:

https://gmtnation.com/forums/thread...canyon-vortec-3500-engines.18807/#post-562876

 

[dna59]

I had the inline 5 Colorado ZQ8 and I absolutely loved that truck. I personally never had any issues with it at all. Many days I'm sorry I sold it and got my Envoy as my Envoy has been a pain in my ass. My only reason for selling mine was I wanted more interior space.

 

[BuffettTruck]

The timing chain issue sounds like a real pain and definitely not something I would attempt in the driveway, but I have to ask, how often is the timing chain an issue? Plus, wouldn't that be something I would be able to hear during a test drive? He says early on that there is no way to put a tensioner or anything on it to tighten it, so I would think I could hear a loose chain rattling away.

Still, thanks for the heads up.

 

[dna59]

@BuffettTruck you should be able to hear a rattle... especially at start up or at specific points in the rpm range.

 

[Sparky]

How does the timing chain differ between the i5 and i6? Same family of engine after all.

 

[mrrsm]

Gentlemen... Please forgive the slant in my views on this ...but such a vehicle with over 150,000 Miles would be an enormous burden on the Young Lady if she could not even get through the first year of ownership without being able to Pass the Smog Inspection due to the internal timing differences that slack chains would cause. That... and the Cascade of Engine Codes that would follow on and keep her Dad up all night trying to chase out those Gremlins. A vehicle with the 4.6L Engine would be ever so much easier to deal with.

As for the difference between the two Timing Chains... The smaller size of the 5 Cylinder Block created the need for a Chain that has fewer links... ergo... One in every 6th Link is Black versus One in every 7th Link for the GM 4.2L Engine. Had they not made this adjustment... they would not have been able to use the same Valve Train Cam Phaser and Intake Sprocket and created more engineering and manufacturing problems without gauging just how many links to remove and maintain an even number ratio... 14 Rotations for the I-6 4.2L... and 12 Rotations for the I-5 3.5L to complete the Black Link to TDC confirmation of a TDC circuit for the #1 Cylinder. The Golden ratio for ALL Valve Trains is that for every One Rotation of the Crankshaft... the Camshaft(s) must Rotate Twice. Timing... is Everything.

 

[cornchip]

14 Rotations for the I-6 4.2L... and 12 Rotations for the I-5 3.5L to complete the Black Link to TDC

Rockauto suggests both Trailblazer and Colorado use the same 168 link chain (OAL of 26 1/2"). If one link rotates around and back to TDC faster than the other, wouldn't that suggest one chain has fewer links? If both motors use the same chain, why does the 4.2 'seem' to be better off? Am I missing something?

 

[BuffettTruck]

Just to throw it out there, to paraphrase the dad from Transformers, "It's her first truck. It is supposed to be like that."

Obviously, I don't want to get something that is going to die in the first year and I don't want to get something where she will have to pay more than the cost to get it fixed, but I grew up/learned to drive in my own beater of a vehicle that I had to put some of my money into if I wanted it to be nice and there were things I got out of that experience that I want to pass to her.. I want her to get two things out of her first vehicle, 1) An appreciation for what the vehicle is, something I think kids who get a new car from the dealer don't quite get. And 2) a basic understanding of the vehicle. I don't we expect her to become a grease monkey, but she's going to know how to change her own tires and even sparkplugs so she doesn't HAVE to get someone else to do it or be taken to the cleaners.

When we go looking, I will be mostly paying attention to the mechanicals, that there aren't any obvious noises that shouldn't be there and, yeah, that the mileage isn't too high. And we'll take it to someone for a quick diagnostics check.

Oh, and we don't have smog inspections here in Florida.

 

[mrrsm]

@cornchip ... Nope. The difference here involves Rotational Crankshaft Velocity vs. Transitional Speed. Think of a 33 RPM records versus the 72 RPM Records of yore. The farther away the "outer edge" any Spinning Disk gets from the Center of the Axis of Rotation... The FASTER it has to move to keep up. You can lay your finger at the inner edge of the Record Spindle and easily trace the motion of the record around the "Axle"... but NOT at the Outer Edge of the record. The Larger the Timing Chain... The Faster the Transitional Speed. Bigger circles only make for much slower Transitional Velocities where Planetary Motion, Gravity...and Kepler's 2nd Law are involved. :>)

But I think you have rescued the situation as I went back to the point in the linked video where the Canadian Kid was holding up the Timing Chain to demonstrate the Huge amount of Slack... and I counted the same (7) Links between Black Links that confirms your observation that the only differences in the linear dimensions between the I-6 and the I-5 is that they lopped off one cylinder... shortening the length of the Crankshaft and creating a need for Internal Counter-Weights externally driven by the Crankshaft to keep the motor from shaking itself to death. Thanks Brother! I stand Corrected!