1986 Toyota 4 Runner SR5 2.4 liter engine with approximately 248,000 miles. I try to do a lot of the maintenance myself by referencing my most prized car repair possession "How to keep your Toyota alive for the complete idiot.”It has saved me an armor truckload of money. Anyway, when I cold start the vehicle the fan sounds as if it is loose and making rattling noises until I get it on the road, eventually eliminating the sound. Could this be the sign of the fan clutch needing replacing? Appreciate any advice.