No need, but a minute or so wouldn't hurt IMHO. Also, do not shut the engine off right after coming off a hard run. Always allow a little time for coolant temps (and hence oil temps) to drop beforehand. So a couple of minutes of conservative driving before your intended shutoff point is a good idea.
The exhaust manifolds are watercooled, but not the turbos, apparently. On the 3.5L EB, the turbos are both water- & oil-cooled.
We have the twin turbo. After changing the oil should we let the engine idle for 15 minuets to let the oil get to the turbo so we do not over-heat the bearings?
From the 3.5L EB's media kit:
Reliable to the Extreme
Turbochargers operate at high speed – up to 170,000 rpm – and under intense temperatures of up to 950 degrees Celsius (1,740 degrees Fahrenheit). Some previous-generation turbos were reputed to suffer from oil coking, in which they would bake their lubricating oil. Because oil coking can lead to premature turbocharger bearing failures, Ford’s advanced engine engineers specified the use of new, water-cooled turbochargers to combat this problem.
“During normal turbo operation, the turbo receives most of its bearing cooling through oil,” said Keith Plagens, turbo system engineer. “After shut down, the problems with turbos in the past were you would get coking in the center bearing. Oil would collect in the bearings, the heat soaks in and the oil would start to coke on the side and foul the bearing. Water cooling – used in the EcoBoost engine – eliminates that worry.”
The new EcoBoost V-6 uses two Honeywell GT15 water-cooled turbos.
“The EcoBoost engine uses passive thermal siphoning for water cooling,” Plagens explains. “During normal engine operation, the engine’s water pump cycles coolant through the center bearing. After engine shutdown renders the water pump inactive, the coolant flow reverses. Coolant heats up and flows away from the turbocharger water jacket, pulling fresh, cool coolant in behind. This highly effective coolant process is completely silent to the driver, continuing to protect the turbocharger.”
Edited by WWWPerfA_ZN0W, 28 September 2015 - 03:21 PM.