weird coolant issue

I've chopped a little off the bottom of the pipe as I had wondered if it was a problem. I guess it is worth carrying out another head gasket test as well. Thanks

dafyddcoch wrote:

Thanks for your detailed explanation of things, espcially of the rad cap. I'll check and re-check. Just bloomin odd that all my Suzuki cars have had this issue from the get-go. Thankfully, my Suzuki LS 650 motorbike is air-cooled!
 

I've only ever seen this on Japanese designs, my Nissan was the same.

European engines tend to just have a plain cap on the radiator and an expansion tank that pressurises, with various small hoses also feeding into it, so the expansion tank cap has the valves, and The Plan is that the expansion tank never gets to the top as the coolant expands.

The reality is that the cheap plastic expansion tanks generally crack when they age and spill all the coolant (e.g. Ford).

 

Make sure the vent in the expansion tank is clear. You could also leave the lid uncapped for a bit, or temporarily replace the entire overflow hose - discarding the cap, with a solid piece of tubing from the rad to the bottom of the tank (you might want to cable tie in place so it doesn't go walkabouts) and see if that improves the situation.
Coolant "overflows" into that tank under pressure, but simply relies on the vacuum created by the contraction of the coolant to suck it back. If air cannot easily vent into the expansion tank it won't allow coolant back into the rad.