Polo 6N2 GTi Overheating Problem

[kraized]

Hi guys, hoping you can help.

I've got a 51 plate Polo 6N2 GTi with around 58k on the clock. Got a problem with the engine overheating intermittently with the overflow tank boiling/steaming and spewing out coolant. It seems to only happen idling sitting in traffic however the fan is kicking in.

I've had the thermo and housing replaced and also I had to replace the Rad hose as it had split at the join between the top and bottom hoses. They also both get hot with the engine running so I guess that rules out a problem with the Water Pump which was replaced at 40k along with the cambelt. Yes/No?

One thing to note is the temp gauge on the dash is a bit erratic. It stays on cold most of the time, may jump up to normal then go back to cold but it always jumps into the red and the dash lamp comes on when the engine is overheating. Is this a problem with the temp switch but doesn't this switch just control the dash gauge and nothing else? I.e nothing to do with regulation of the engine temp itself.

I have been told that because the Rad hose had blown it maybe an issue with the head gasket due to the pressure build-up in the hoses. Is this correct?

What do you guys think?

[georgen]

open expansion bottle and smell it, do you smell petrol/oil.
you can also make sure coolant level ok and start car, make sure the heaters are in the hot position and let car run, can you see any air bubbles coming up into the expansion tank, squeeze all hoses repeatably when system is at normal temp and pressure has built up how hard do your hoses feel, rev car at a fast idle for 10 mins then check water level, hoses for pressure and temp, all hoses including the rad itself should be warm. the hoses would feel hard until the thermostat opened if all was well then go softer to squeeze.if head gasket was leaking into water jacket, the pipes would be rock hard all the time.
you would have to keep checking all the time this is not a 5 min procedure and please be careful in case a hose blows or the fan starts whilst your checking stuff.