Would an engine flush reduce knocking in my Saab 9000's engine?
I have an N-reg Saab 9000 CSE turbo automatic. When the engine is running it knocks on the right hand side and gets louder while driving. I have asked a few people about it and have had different replies, like it needs an oil flush and change to stop the noise, or the big ends looked at. Do I use some engine flush and change the oil and filter, or do I just change the oil and filter? I've heard that an engine flush will damage my engine and the car has done 137,000 miles, so I'm unsure if it is safe to use an engine flush?
What you haven't said is whether you have serviced the vehicle regularly until now. If you have, then I cannot see why you need to use engine flush. Even if, as you suggest, the big ends might be worn, an engine flush will not make them any better. One would suggest that a change of engine oil and filter will not do the engine any harm, and can only assist in ensuring the engine continues to run well.
Answered by Alan Ross on