Service Before Failure...

[AzDragonLord]

My 2009 Sierra will be reaching 100K miles in a few months, and I'm already gearing up for things like plugs, fluids, etc. Should I be changing out things like the water pump and timing belt during this milestone?

[DaveH71]

Water pump? nah. You don't have a timing belt, you have a chain and it's not a service item.

 

Plugs, Plug Wires, Coolant, Trans Fluid, Diff Fluids, Transfer case fluid, Air filter? Yup.

[kstruckcountry]

I'd do the thermostat too.

[txab]

Belts and hoses

[Kent2500]

I would pressure test the cooling system.

[AzDragonLord]

Thermostat.....good idea!

[KARNUT]

Last truck I had that long was a 04 Z71, I called my shop owner friend about the plugs. He told me they would last well beyond the 100K recommended change, and wait for the light. At 180K when I traded the plugs where still good. The only thing I change was the coolant at 150K per manual, a wk later the water pump went out. That and back brakes were it on that truck, best one to date.

[AzDragonLord]

... I called my shop owner friend about the plugs. He told me they would last well beyond the 100K recommended change, and wait for the light. ...

There's an indicator light for plugs??

[KARNUT]

There's an indicator light for plugs??

Check Engine

[00Silverado4x4]

To the best of my knowledge, the Check Engine Light does not illuminate to tell you to change plugs. It would light up to tell you there is a problem with the ignition system.

[KARNUT]

To the best of my knowledge, the Check Engine Light does not illuminate to tell you to change plugs. It would light up to tell you there is a problem with the ignition system.

Like a miss fire, from the plugs. I always carry tools in my truck, I had a 98 ford that had a head gasket problem every once in a while a plug would miss fire. The check engine light would come on along with a miss from the engine. I change the plug, the light would go off. Never happen on the 04, I traded it at 180K.