I bought a 2000 GMC Sierra, new 10 years ago and just started to have lifter noise. The original motor has 323,000 miles on it and would love to keep it. Is the noise a sign of bad things to come? Thank you.
Never used it before, so if I add it to the crank, do I have to drain a quart of oil to add a quart of MM, or do I add it at the next oil change? Thank you.