Timing belt or chain

I have a 2003 Trailblazer. Does anyone know if this thing has a timing belt or is it a chain? It has a inline 6 cylinder.
Thanks

Chain.

Thanks!

Speaking of which, how long do chains last?

In my Talon the timing belt needs to be changed every 60k miles, but that is a belt and with those the tensioner just stops working.

What is involved in a chain setup?

The chain is supposed to last the life of the engine. It's kinda similar to a T-belt in that it has a hydraulic tensioner. The tensioner pushes against a rail that pushes against the chain to keep it tight. There's no idler sprockets IIRC. OHC chains are nice, but if they do let go, they usually tear the font end of the engine off with them. I dunno if the 4.2L is an interference engine, but valvetrains equipped with hydraulic lash adjusters (like the 4.2L) are typically non-interference.

Joel

..What is involved in a chain setup?

Here's a cool link. Check out pg.10 for the chain: http://media.gm.com/division/powertrain/news/4200_Tech.pdf

Joel

Actually it's an inline 5 cyl.

Actually it's an inline 5 cyl.

The 4.2L is a I6. The inline 5 is only used in the colorado/canyon pickup, and the H3. The 2.2, 3.5, 4.2 (4,5,6cyl) are the same family of engine.

G/luck
Joel

Joel, appreciate the link to the write up on the 4.2 I6....It makes me feel like the decision to buy a TB was a good one, not that wev'e had any problems with ours (25K Miles on it so far)....but the engine seems well designed. Do you know if/when GM may start putting this powertrain package into their 1/2 ton pickups.....it is definately a good combination if the truck is going to be an around town and every once in a while hauler. This would steer me more toward a Chevy truck than a Ford....

Chuck, I have yet to hear anything in regards to GM using the 4.2L in anything other than the TB 360 platform. You would think it would be an ideal candidate for base model 1500 p/u's. Inline engines are a great selling point. IMO- GM has to work on a better transmission and gearing to mate to the 4.2L to improve power feel and economy.

Joel

Yeah, too bad the 4.2L I6 will probably die in 2009-2010 when GM axes the GMT360 platform as it is only used in our platform. The Coly/Canyon/H3 all have the littler brothers to the I6, 2.8L I4/3.7L I5 (bigger than 04-06 displacements), but those engines are underpowered in the GMT355 platform IMO. Too bad the I6 is too long for their platform, it would be nice to have another platform using the I6 so we could steal parts like a manual trans (GMT355s have manuals).