Cooling flush

[autojohn]

I'm about to do a full service on my 340 DL engine B172. I was wondering if I need to flush out the cooling system. The car's a 1990 model. I've owned it since 1995 and it's never been flushed in that time. If I do have to do this, what is the procedure please. Is there such a chemical on the martket that I'd use pre-flushing please.
Regards.John

yeah its worth doing, basically you just unplug the lowest pipe, let it all drain out (theres some cylendar head bolts to open too), then put a hose in one pipe, turn it on full pressure to clean it out and refill!

[autojohn]

Thanks Hugh,I'll do that tomorrow if the weather permits mate. I assume you mean cylinder block bolts when you say cylinder head bolts?
I think they're on the near side of the block.
I've been wondering if that chemical they use in central heating systems to clear out sludge would work if left in the cooling for a few days. Have you ever heard of it's use at all?
Regards.John

yeah thats the ones

i dunno about chemicals - you'd have to be very careful not to burn any rubber away - the only thing i've seen reccomended is putting a high pressure hose thru each section..