1996 VW Polo 1.4L Open Air - strange starting issue

[shirike]

Hello, New owner of the above vehicle and everything is in lovely condition except for 2 issues (which may be related).

1. Temperature gauge on dashboard does not work but I don't know if this is due to the gauge or the thermostat.

2. From a cold start the car starts first time every time but sounds a little wheezy. However, if I've parked up somewhere and switch the ignition off but try to start the engine up again straight afterwards, the starter will whirr then it does a strange droning sound then a clunk and will cut out. It will start every time after that though.

I've done some googling and one website mentioned a faulty coolant sensor can result in starting issues (and it does seem like the car may overheat and that's why it has issues when I've just turned it off after a runabout).

I'll be replacing the coolant sensor, changing air filter, changing the oil and bleeding the brakes at the weekend..............


.......so can anyone give me any other hints for diagnosing this issue if it turns out not to be fixed by replacing coolant sensor?