98 Skoda Felicia hot starting problem

Check and test the coolant temperature sensor and also do below

Next time it refuses to start don't wait for it to make up its mind-do below immediately to determine if its fuel or spark problem

https://www.2carpros.com/articles/car-cranks-but-wont-start

Get a helper disconnect a sparkplug wire or 2 and ground it to the engine atleast 3/16 away from ground-have helper crank engine over-do you have a snapping blue spark? If so-you have a fuel related problem, Do you hear the fuel pump come On when you turn key on? If not check fuel pump fuse and fuel pump relay if okay-check the fuel pressure to rule out the fuel filter/fuel pump/pressure regulator and listen to the injector/s are they pulsing or hook up a noid light. No snapping blue spark continue to troubleshoot the ignition system-power input to the coil/coil packs,coil's resistances,cap and rotor,distributor pick-up coil, ignition control module, cam and crank sensors and computer Note: If it doesn't apply disregard it and keep testing

Thanks Rasmataz one thing, but important i forgot to mention that it has a diesel engine oops but all the other things you mentioned have been checked and found to be working correctly bit of a puzzler don't you think many thanks for your reply.
Dave.

Thanks for your reply but it has a diesel engine all the other components you mention are working fine don't know what happened to the title I don't remember putting actuator in the main heading anyway many thanks for your reply bit of a puzzler this one.
Dave.

Could be air in the system try bleeding it out

Many thanks rasmataz but I think I found out the problem maybe?
I had to fit a new starter motor to the car and after a day or so I put the temp sensor connector back on the engine and it starts ok now
even when hot I was thinking maybe it might have been down to the starter solenoid controlling the hot starting I'm not sure but it works fine now, hope this might help someone else who may have the same or similar problem.
Many thanks rasamataz.
Dave.

I have te same identical problem on mine (97 diesel 1900). I have had the starter motor ovehauled and changed ALL the heater plugs. It starts fine when engine is cold and heaters are allowed to operate. When engine is slightly warm, a sensor on the engine block prevents the glow plugs from coming on and starting becomes problematic. In summer it gets worse of course because the engine does not cool quickly enough to let the glow plugs on. A green sensor sender on the engine block seems to be the culprit, it cuts out the hglow plugs at a temperature that is too low. I will have to fork out on a sender plug, and it isn't cheap. Quite what is the use of this sender is not at all clear. Any intelligent user will decide for himself whether there is a need to activate the glow plugs and at what temperature. It seems one of those unnerving clever-by-half devices.

on the same score, I am tempted to bypass this sensor/sender with a push-switch so as to avoid running the poor starter motor to an early death. But it seems cak a way to cheat technology. What a merry-go-round!
Yes, I could measure the temperature and find out at what temp the blighter switches on and replace it with a higher temperature one regardless of manufacturer recommendations.

I replaced the sender unit with a new one and still had problems the new stater motor has rectified this problem now, the only way to start the car when hot is to remove the wire to the sensor on the block but your temp gauge will not work but the car will start even when hot.
Dave