Hi, mines an LT1 V8 and when I got it the heater was blocked up. Flushed out an enormous amount of crud with a hose pipe. Was OK till I had to replace some hoses, refilled but another problem emerged, water pump seals. What I flushed out was relatively clean but there was a little sludge at first. When I refilled first time I used Halfords OAT and seemed fine, didn't cause water pump problem, the seals were awful, some sticky silicon stuff had been used .. too much! Like half dried evostick, bolts felt barely done up.
You can flush it but I'd flush it well with water. Wouldn't personally use a chemical cleaner on such an old engine as you don't know if it's had a sealer added in the past which may leave a floating crud? I'd flush it with water till clean, refill with coolant and keep an eye on it. The sludge could be sealer remnants? If there is anything wrong You'll need fresh coolant to find out. Hope that helps.
Tom
|