2002 V6 Grand Vitara needs TIMING CHAIN replacement?

[chronophile]

Hope to get advice on whether I should go ahead and let PilHino proceed on the ff

1. My car is an 02 Grand Vitara V6 A/T with 54,900km on the odometer.

2. Car does about 8,000-9,000 km a year, 99% on-road.

3. Car was not used for about a week (last week). When I turned on ignition last friday, July 18 (aircon still OFF), I could hear metallic noise. I initially thought alternator bearing as source of the noise. However, noise went away after idling for about five minutes.

4. The noise did not return in the last three days.

5. I checked in the car at Pilhino EDSA this morning (July 22) for the 55KM service interval, and aside from the standard scheduled oil change, I requested that they also check:
a. the origin of the metallic noise (which disappeared in the last three days),
b. slight oil leak coming apparently from the crankcase,
c. the slight play on the auto shifter which makes it feel loose in use.

6. The Service Advisor this afternoon told me that the noise is coming from the timing chain which requires replacement already. (I wonder how they came to that conclusion as there was no longer any noise in the last three days even til this morning when I checked in the car at PilHino). They claim they have already encountered and fixed that kind of problem with that car model before.

7. They are suggesting that all three jobs be done together over the next 3 to 4 days as these are major works:
a. replace timing chain to fix the "noise" I encountered three days ago (which never came back, as I already mentioned)
b. replace o-ring in the crankcase area which is causing the oil leak.
c. replace the auto shifter bushing which is the cause of the play/loose feeling on the auto shift lever.

I called Filmar (Katipunan) and they say they do not do timing chain replacement.

My major concerns are:

1. Do timing chains ever need replacement? I thought only timing belts needed replacement.

2. Should I let PilHino perform the timing chain replacemment (even if the noise went away)? They are charging me Php33,000 (initial estimate, parts and labor) for all the three jobs - 7a, 7b, and 7c.

Would appreciate your opinions. Thanks in advance!

[Bogeyman]

1. Do timing chains ever need replacement? I thought only timing belts needed replacement.

Timing chains are more durable, but it doesn't mean they're indestructible.

Compared to timing belts, timing chains are largely immune to the effects of heat -- but they are vulnerable to stretching as they age. This increase in length can have adverse effects on camshaft timing, especially when the chain becomes loose enough to rub against the inside of the timing cover. Also, timing chains and sprockets eventually wear out, changing the precise timing of the valves to the point where replacement becomes necessary. Although timing chains have no specific service intervals, it still makes good sense to periodically have them checked for wear and tear.

This is why I appreciate timing belts more, since they have planned obsolescence built-in, making the owner exercise due diligence in replacing them at specific intervals.

But if you're sure that the metallic noise went away before you brought the vehicle to the casa, you can always get a second opinion. Baka naman tensioner yung problema, not the chain itself.

[Bogeyman]

*double post*