What are the symptoms of a timing belt going bad?

It'* not for my car thank god but have a friend who went to a not so trust worthy shop and they said she needs a new timing belt..

It idle rough, but accelarating is the same. gets occasional SES light and idles rough then.

I'm thinkin it needs a tune up.. mainly new plugs and wires as it'* over 120K KM with no service done.

I also thought that when the timing belt has stretched, shifted or whatever to the point that it idles rough you will notice a loss of power during normal driving conditions also, along with a a constant ticking of the valves.. what other symptoms are there (next to pulling codes) that would support that a timing belt is going/gone?

Yea, I sure hope it wasnt your timing belt or we would have some problems

Anyways, A miss or inconstant idle could be a timing problem. But where it accelerates fine but stops accelerating fine when the SES light comes on indicates some sort of sensor failure, maybe crank sensor?

IWhy dont you have your friend get a scantool reading and come back with it

Does this other car have a GM 3.8? If so, it does NOT have a timing BELT - it will have a timing CHAIN. Not as much worry about it breaking as, say, the timing belt on a Honda CRX that bent all but 3 valves when it broke!

A good tune up is probably all you need if it'* a 3.8. Keep in mind that can be costly too, if you have to change sensors, plug wires, & things like that!

If it'* NOT a GM 3.8 and it does, in fact, have a timing belt it would be the better part of valor to go ahead and change it. In this case the preventative maintenance is well worth the cost. I know this from first hand experience!

unless you have an non-interference head, then you can just let timing belts go as they wish =)

unless you have an non-interference head, then you can just let timing belts go as they wish =)

*Someone deleted their post!, now it looks like im talking to myself... Im not crazy*

It'* not a 3.8.. it'* the lil 4 banger on a 98 cirrus.. from what I was told it idles rough.. accelarates fine.. but when the SES is on.. it accelarates horribley too.. A crank sensor aie? Haven't thought of that yet.. and that might be the issue since its intermittent SES light on and accelarating problem.

yea, the service interval for the timing belt is every 60,000 miles, I would definately get it replaced at least as some PM. Also a possibility is that one or two notches of the ttiming belt have been broken off so it has sliding which Ive seen happen before. The repair is rated at 2.8 hours shop time and doesnt look like too difficult of a procedure, and like jr's3800 said your friend would be quiet sad if that belt went, smashed valves is one thing, but on this lexus Ive seen valves embedded into pistons which you might as well junk the engine and get a new one.

humm.. I wonder if my bro had his changed.. he also has a cirrus (but it'* the V6 version) .. and its done up pretty nice.. only 96K on the belt? eeshh.. guess I"ll ask my bro to find out if they have a chain that she can opt for.. how long does ours last? ( both NA and SC'd.. is there a difference between series I and II ?) ( just wondering cause Tamara'* 95 has well over 200K and it still purrs like a newborn.. only thing that car needed was hub bearings, sending unit, and recently front brake rotors and calipers.. the usual maintainance stuff )

the Series II should never really need it. The LG3 engine (3. needed them quite often because of plastic gears, the LN3 needs it at around 130,000 miles because of a poorly designed tensioner.. The L27 shouldn't need one ever either.

Intermitten SES and acceleration stumble sounds like to me a bad cat. Has she had that checked?