sticking valves

[Briggsjag]

Hi forum, Has anyone had this problem. The engine in my devon (1.9 DG) over the last month or so has developed a knocking noise. kind of narrowed it down to a sticking valve, as it will free itself after a few miles of driving and then stays free for a few days wheather used or not. however drove around tonight and did'nt free off. can anyone suggest an oil treatment worth using or is it a cylinder head strip down thats required. Thanks. p.s. I've searched the site and came accross Flower Powers's post entitled "load knocking sound." I wish I hadnt looked.

[toomanytoys]

Its not a sticking valve, its the "normal" lazy hydraulic lifter problem.. correct oil is often simplest cure... you need a mineral 15w40 or if its tired a 20w50, nowt thinner...
Short journeys they dont like and will show it up often...

[Briggsjag]

Thanks toomanytoys, the van seems to idle fine just noisey, but lacks power when driving as if its running on three cylinders. Would this be another sign of a lazy hydraulic lifter?. was going to try an engine flush but a bit wary of the stuff.

[T'Onion]

do an oil change , take it for a good 40 mile run and then see how it is

[toomanytoys]

As T'O says.. if it hasnt had an oil change, do one... then take it for a good run...
Lazy lifter will also give lwer power until its pumped up... its poss there could be other issues, but without seeing it its very difficult to diagnose, lazy lifter is the most common and likely thing...

[Briggsjag]

Thanks Guys, i'll give it a try.