78 super beetle, i was going about 45 in 2nd gear and engine dies. Pull over and turn key starter relay engages but no crank. I thought it might have overheated so i let it sit half an hour and try again. This time starter engaged and engine turns over a couple times but wouldn't start. After that i just get the relay click no crank no start. I tried the crank pulley with a wrench and it wouldn't budge now I'm afraid the motor is seized. What should i check? I haven't pulled the plugs, no bore scope to check cylinders, i could take the valve covers off but with the crank not turning i wouldn't know how to check if a valve is bound or anything.