Most belts can be stopped from squeaking by adding lubrication. This can come in the form of belt dressing or even common bath soap.
It won't be the engine that's squeaking, it will most likely be a belt, take it to a mechanic to get the belts tightened up.
Squeaking belts are the result of improperly adjusted tensioners and pulleys. The belt slides over the pulley and squeaks. Using a lubricant would defeat the purpose. Also I'm not sure what affect wd-40 would have on the material the belts are made of. To get them to stop squeaking tighten them up. Make sure you use your manual and don't get them too tight.
Squeaking or tearing of the rubber on the belt
loose belts
To stop your kitchen and dish washer door from squeaking try oiling or greasing the hinges.
Could be one of your belts.
Try sprinkling talcum powder over it then sweeping it up. It should get between the cracks and stop the squeaking.
Lay still.
One of your belts may be loose or in need of belt dressing.
Loose belts
Put a small dab of clear dialectic grease on both sides of the belts and the squeak will go away.
The belt needs to be properly tensioned and aligned. It may need to be loosened or tightened, or lined up with the pulley. Worn belts should be replaced. Occasionally belts may squeal or squeak even if properly installed. Although it is not recommended where other problems exist, there are retail sprays that can lubricate belts safely in these circumstances.