1987 Mercedes 300SDL Fuel leak 300,000 miles

[ron59b]

Good evening all

I have an 86 SDL, but I'm posting this for my buddy and his 87 SDL. He's owned the car about 8 months and was told he had a fuel leak that has gotten worst over time. He told me he's noticed a puddle of fuel near the front center behind the grill area. He said it's about a test tube full give or take.

My question is where should we start in attempting to identify the possible leak? He had the car in for an inspection recently. He also has one glow plug that is bad.

I would appreciate your suggestions before I take look at it. It would be nice if it's a DIY fix. The car has been his daily driver.

Thanks for you input.

Ron