3.4 DOHC with timing belt AND chain. Chain fail?

[Teardrop]

I was investigating in the haynes manual about some of the things in these engines...
Looks as thoughthere is a timing chain buried that drives the intermmediate shaft.
I know it has it's own tensioner.

The question is - what is the likelihood of that chain breaking? I read somewhere that timing chains with a tensioner are less likely to break given it cannot just slap around when it stretches say like on the older 3.1 GM.

Is there a way to really check it's condition, even get an idea, without having to pull everything apart? The replacement instructions look to be a huge job.

BTW my car has 194,000 miles and I have no idea what maintenance or repairs have been done in the past. Also, nothing has broke yet but I have this weird paranoia about timing belts/chains breaking.

[RednBlack]

Yep. There is a timing chain buried in there. Only one way to check it though, and if you get that deep, change it. Not much point in not doing it.

[pocket-rocket]

To check for slop you can do like the old timers would do with a v8 and "rock" the crank pulley clockwise and counter clockwise. A good time to do this would be when you do the timing belt so you can see right there when the lower timing belt pulley starts to rotate again. I've never changed the chains on either of my cars. The 92 has ~144k on it and the 91 I believe has ~170k, both of which have hard miles on them since I've bought them... >.>

[Teardrop]

If I recall correctly there is a tensioner on the timing chain, so in that case if there IS a lot of slop, that would be REAL bad, means the chain is stretched to the limit.

I now understand why the belt takes such an akward procedure, due to the cams wanting to adjust as the tension is set...
I can't really describe what I imagined going wrong but nothing I have heard correlates to what I was imagining...

And also folks, thanks much for the help... my next steps - "manufacture" some hold-down tools, get the belt, and actually DO the job.