loud valve

when i start my van after it has sat for a while ,i get a tapping from the engine,it does go away after awhile.it has 190,000 km.i was told to add a product called rislone engine treatment by bars when i change the oil,run it for 500 k then change the oil again and add bars oil treatment.problem should be solved.yes or no.

I've never used rislone but have used auto-rx. Auto-rx will clean the deposits in your engine that cause the lifter issue. It will also clean ring packs to increase compression and decrease oil burning. Have a look.
www.auto-rx.com

There is another product which can be used to clean the varnish and gum from lifter bodies and disc metering valves. It is added to the crankcase, and along with excellent cleaning properties, it lubricates better than most oils. it can actually soften seals and restore sealing once the initial gum and varnish are dissolved and washed away. It doesn't only help clean lifters, but can clean sludge and varnish deposits from rings and ring lands to help restore compression and provide better ring life. best of all, once it's in the crankcase, you can usually increase the oil change interval to at least 6,000 miles (10,000 km) without problems.

It's called polyalphaolefin, which is the main ingredient in Amsoil and Mobil 1. At only 118K miles, it's a good time to switch.

BLUE BOWTIE =is this product you are talking about ,synthetic oil,if not could you be more specific,THANK YOU.INFO APPRECIATED.

Synthetic oil will not clean deposits AFAIK.