Q: Loud rattling noise from engine.

Hi there. Open the hood and check all around the engine compartment for something to be loose. When you hit the guardrail, the vehicle may have jolted hard enough to dislodge something and make something in your engine compartment move around. Check the air box, the battery tray, the coolant reservoir, the radiator, the fenders, the hood mounts, and the wiper system. Also, if you jeep is 4WD, check the drive axle on the front and see if the universal joints may have cracked making the rattling noise. Anything could have came loose and is causing the rattling noise. If you need further assistance with a rattling noise, then seek out a professional, such as one from Your Mechanic, to help you.