Do you need to allow for more fluid when running external coolers?

[mofoco1]

I have asked this before and got a less than satisfactory answer, I have 2x 18" coolers one for the trans and the other for the powers steering. The trans cooler sits at level with the transmission, should I fill the cooler with fluid prior to running it or will there then be too much fluid in the system, the cooler holds about a quart. I was thinking it would create starvation if there was a void, No? Same with the PS cooler, but it obviously sits below the pump? Thanks again....Mo

 

[Viperwolf1]

It's low enough there shouldn't be any problem with it draining into the pan when not running. You don't have to fill it before the first startup. It will get filled before you get the trans filled completely.

 

[patterdale]

What Viper said plus yes. You have created and extra quart of capacity in your system so it will take another quart to be full. The trans will circulate the oil as quick as it begins turning.