2003 GMC Envoy 6 cyl.

[josh309]

I'm new at car repair. I have a service code of PO128 - was told to replace thermostat. Where is it? Would like to see a photo of where it is under-the-hood. Thanks for any help.

[maxwedge]

Welcome to AF. Follow the lower hose to the outlet on the block, after draining the radiator, remove the t'stat housing.

[josh309]

Originally Posted by maxwedge

Welcome to AF. Follow the lower hose to the outlet on the block, after draining the radiator, remove the t'stat housing.

Thanks for the quick reply - which lower hose to what outlet - the radiator has to be drained?! what does the t'stat housing look like? I told you I was new at this!

[maxwedge]

Don't take me wrong here but this may be a little too much for you, follow the lower radiator hose under the l/s of the block to the T'stat , the radiator must be drained from a difficult to reach petcock under the lower lt corner.

[josh309]

Ok - you're probably right. Does it hurt to drive this car knowing what the code means - the 'check engine/service engine' light has gone off. The car isn't overheating - the gauge level is slightly below the middle of the gauge. Thanks.

[maxwedge]

No, you will be ok, it probably is running cooler than normal so you have some time with this.