Originally Posted by BGTV8

Guys, fiddling with the under-engine shrouding affects thge air-pressure behind the radiator and can affect the amount of air drawn thru the radiator .... you might be cooling the sump. but you may also be affecting the efficiency of the radiator .... take care to monitor engine coolant temps with mods like this.

I drove a Ford XR8 Ute (Oz spec "truck") with the hood unlatched (on the safety catch) for only 4 klicks having filled the washer bottle at a freeway services area several years ago, and was puzzled as to why the coolant temps were elevated ... had gone from normal 92DegC to 105DegC .... it was because air was going over the top of the radiator and pressuring ithe engine bay behind the radiator and radiator efficiency was compromised ... same thing can happen if you are letting air into the engine bay from below.