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Flushing the rad with a rad flush.Tips and advise please. - Engine/Ancilliaries - The Lotus Forums - Official Lotus Community Partner Jump to content


Flushing the rad with a rad flush.Tips and advise please.

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Hi,I have just finished a marathon rebuild on my S4 Esprit.The water system was red rusty,I have cleaned and unblocked the heater rad and all the hoses.Now that I am running the car I have noticed that when the rad fans cut it(which is pretty quick) they take a long time to cool the water down.I have a snaeky feeling that the veins are blocked with rust and sludge.Has anybody used a rad flush,are they effective?? Cheers Paul G.

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What did you find out Paul?


Anyway, I am changing my coolant from something green (dark) which PO said was correcr. Engine's been rebuilt a couple of years back, and only very few miles since then. Sins very nicely.

So, I added one bottle of radiator clean (I've used than on other cars before), and warmed up, then let idle and a Little above for ½ hour, then coled Down for an hour, then I drained the system, added many Liters of demineralized Water, started and bled the system, ran to temp and waited untill two fan cycles had occoured, then shut Down and wait untill Cold, then drain Again. This I did three times in total, using only demineralized Water.

Now, I am ready to add Castrol Radicool SF and demineralized Water in 50/50 mix.

Then I thought: why not change some bolts on the shroud and all? and clean the radiators while at it? Every bolt broke and I have to take everything apart.


That said, I couldn't really see any dirt inside the system, or old minerals deposits either. It seems pretty clean.




Nobody does it better - than Lotus ;)

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