Definitely from the front of the engine?
I've had a mysterious squeak or squeal under load that eventually turned out to be the drum handbrake. It was caused, I think, by the friction material separating slightly from the metal part of the shoes. Eventually it was quieted by putting on new handbrake shoes. It happened again a few years later, but I recognised it and did the handbrake shoes again. It's been quiet ever since.
Does it happen when you rev the engine when the car is stationary? Or only when moving? If the latter, then maybe it's something in the transmission - such as the handbrake.