I was told when I had my truck in the shop 2 months ago that I needed new valve cover gaskets. Have put 300 miles on it since then.

How serious of a problem is this? How much to replace?

I asked how to tell when they will be bad, or really need replaced, he said oil in the driveway...

It's a 99 5.4 with 124k.

Thanks!

 

I wouldn't replace them unless I could see oil seeping from the valve covers and/or had an oil burning odor in the engine compartment or if I was having to add oil between oil changes.