I too have the same problem with an engine knock, louder when cold. 97 catera has engine knock,will knock when started up and quiets down once it warms up ,but does not go away entirely. I purchased this car during the beginning of summer and did a tuneup and oil change right away. At that time the car had 103,000 and now has about 113,000. Somehow I think this knock is normal for that engine. The guy at the oil change place made mention of a knock on the Catera without me saying anything about it. It was warm and not making the noise at that time. He suggested that 5w 30 would help with the knocking noise. I did not want to go that route because the last oil change was 5w30 and that caused an issue with oil pressure dropping to low. I have checked around the engine for anything knocking and tightened everything up. Poring SeaFoam into the engine seemed to help as I thought sludge may be the cause. Somehow I think that the knocking noise is coming from a valve lifter on the drivers side, but I am not sure cause I not a mechanic. Am I on the right track or should I not worry about it?
01 Catera engine knock when cold. on 2001 Cadillac Catera
by meierr69 in North Olmsted, OH on January 11, 2014
ANSWER by ProfessorG on January 11, 2014
The knock needs to be found, before you have a bigger problem. Just one word of advise, That engine is a Volkswagen engine, could be very costly if ignored.