I Have a Datsun Safari 1983 2,8L petrol.
Recently I was driving off road with it and the next morning the fan belt was making this squealing noise. So I adjust it and all was well. 300km later a new squealing sound started. It only occours when I drive over a speedbump or uneven surfaces and then I have to switch the engine of before this sound stops.
I checked to see if it could be the fan belt again or the starter motor or radiator fan but no. The sound of the starter motor or loosen fan belt is not the same and there is more than enough clearance between the radiator fan and its casing. My Datsun does not overheat or loose power when this sound starts.
Every time I drive it now this squealing sound is triggered more easily and becomes louder and louder. It also doesn't leak oil or water. There is only a small leakage in the braking system but the squealing sound doesn't came from the brakes,even when I come to a complete stop this sound will continue while the engine is running. I can't locate the source of this high-pitched squealing sound and this sound is of a sort that I have never heard of before anywhere. Its like when you making a squealing sound while keeping your nose closed.