When should I think about replacing the timing belt on my '11 c70 t5?

 

The interval is in your owner's manual (also available online). Assuming you have the B5254T7 engine (the 5 cyl turbo will have a "67" code in your VIN), its 10 years or 120,000 miles including the idler pulley and tensioner - which ever comes first.

 

Thanks alot,,,,another question,,,,I'd like to change my spark plugs. I started to do so, the plug was very hard to loosen(didn't get it out). Wonder if I should or could, spray alittle "buster" on them to get them out. I've had the car for two years,,,lord knows when the plugs have been replaced. Thanks,,,Bill

 

I don't see why not use a little PB Blaster. Just make sure you have the right sized deep socket and extension so you can get a "square" access to the plug. I typically use a 1/2" ratchet with 6 inch extension and test your "lefty loosey" before strong arming the plug. Just clean up before reinstalling, not sure of exact spec for tightening torque, but is should be in the 20 ft/lb range. I just did the plugs on my daughter's S40 and they had been in there for ages so I know it can be a bit of a surprise when you need to work a bit harder to remove than expected. I didn't bother with any blaster, just gave myself enough room to work the ratchet handle.