Coolant Rad Cap Faulty.

[deMort]

If you get a white crusty deposit on any part of a coolant system then it indicates a small leak and the antifreeze is trying to seal it .

For a rad cap .. if it looks like the image below then its leaking ... the pressure side of the cap is failing .

The residue over the drain channel also confirms this .

Drain pipe exits over no.1 coil .. which is why these often fail .. mechanics tuck the pipe behind the heat shield there so this doesn't happen .

 

[montygraphics]

Thanks Demort. Useful info as always.