My car sounds like a sewing machine, when it's at idle. Is that bad?

 

I have seen bad/failing valve retainers lately. Once you have the cam carrier off, you can inspect the retainers. If you have one that is cracking, the valve stem will be recessed into the retainer(once you see this compared to a good one, it is plain as day) and the retainer is no longer flat, it has a bowed look. You can't see the cracks unless you remove the retainer since it cracks on the underside where the keeper rests in the retainer. . Once the the retainer fails, the keepers have nothing to grab and guess what, you valve has just dropped. You will not have any warning if this is developing until it is to late.

 

[QUOTE]Originally posted by mxt_77