1997 pontiac bonneville again--timing chain


#1

I just bought a 1997 Pontiac Bonneville with just over 100,000 miles. My question is about the timing chain, specifically–should I replace it? If so, when? My owner’s manual says nothing about this in its list of regularly scheduled maintanences.


#2

I wouldn’t worry about it unless it is making noise. I have a 97 Bonne with 260k miles and the original timing chain. Chains rarely need to be replaced.


#3

Just for my records–what sort of noise would it make, and where would said noise be coming from? (It’s not making any noises, I just want to know what it would sound like if it was).


#4

I can’t think of how to describe it, except a metallic type of sound coming from your engine, not any of the external components. Seriously though, don’t worry about it. There are tons of other things that are far more likely to go wrong with your car before the timing chain. If you want something to worry about, check out this article:

http://www.bonnevilleclub.com/forum/kb.php?mode=article&k=38

This has happened to every bonneville of that era I have come in contact with.

For more worry, the transmissions in these bonnevilles are underbuilt. They are the same ones GM hooked up to their 3.1 liter engines. They like to fail under the 3.8 liter.

Hopefully you can still sleep.


#5

The last thing to worry about on a Bonneville is the timing chain wearing out. If you are the type to worry; you wouldn’t buy a 97 Bonneville. Just drive.


#6

Actually, I am aware of the intake valve issues.

The transmission has just been given a thorough going over–and it’s shifting beautifully and all that jazz. I did read that there were occasional problems with the valve bodies on the 1997 model.

Pretty much, I’m not the type to WORRY per se, but I do like to have my bases covered. I had three seasoned and nicely credentialed mechanics look it over real good–two before I got it, one after. One pronounced it “a pretty good car,” which in my experience is mechanic speak for “no worries.” The other two told me, independently of one another, that with my penchant for upkeep, there is no reason why this car can’t easily go another hundred K. I wasn’t even expecting to keep it around that long.


#7

A worn timing chain usually appears as a tinny and erratic rattle. Think of a dozen Styrofoam peanuts and a marble in a coffee can and shake it. The chance of having a timing chain problem is near non-existent; they usually outlast the car. The problem ones are the ones that have seldom seen an oil change.

My neighbor has a '96 Bonneville and had the intake problem crop up. It was not that big a deal. He works for a farm supply outfit and did this job on his own car during the work day. Lunch hour and both A.M and P.M. coffee breaks was all the time he needed. Other than that his '96 has close to 200k on it, is driven daily, and runs just like the day he bought it used; about 6 or so years ago.
Change the trans fluid on a regular basis (30k mile intervals) and you probably won’t have a problem in that area.


#8

My experience with the 3800 is that the timing chain will go out anywhere between 150K and 250K. I had one that gave absolutely no warning and another that would make a hard rapping sound against the front cover. I really wouldn’t worry about it at this point and be more concerned with the intake leak issue.


#9

Well, next question then–and I suppose I’m done–how would I know if the upper intake was giving me troubles? I don’t know much about cars, except that I’m usually quick to notice when something isn’t running as smootly as it used to.


#10

Agreed, a worn timing chain (sprocket(s) and/or tesioner included) usually makes a rattling or rapping sound. Something similar to a badly collapsed lifter. They outlast the lives of most people’s cars…however most don’t keep their cars for hundreds of thousands of miles!

Styrofoam peanuts? Wha?


#11

The point behind the Styrofoam peanuts in a can analogy is that they will cushion the marble most of the time and prevent a steady rattling sound. The rattle will be erratic in nature, much like a worn chain.
Testing for a worn chain is easy, even on non-distributor equipped cars. Simply make a few marks around the circumference of the harmonic balancer, connect a timing light to a plug wire, start it up, and note if the reference mark is wavering around a bit.
Regular oil changes will keep a chain going longer than anything else. My old Mercury had 420k on it when sold and it still had the original chain in it; and the chain was still tight as verified by the timing mark.

Keep an eye on the engine oil for contamination or being slightly overfull all of the time since that could point to a coolant leak from the intake. The system could also be pressure tested but that could be iffy since it could be one of those good one day, bad the next type of things.
The best cure is to go ahead and repair it in advance if you’re going to keep the car for a long time.


#12

Hey you have a Bonnie 1997?


#13

Probably not anymore. It was from 2008.