Wooosh Wooosh ...... Check all your intercooler boots. You could have a clamp or boot coming loose, causing this to only happen under load. The fan does plenty of Wooshing.

I was losing coolant only when towing or railing up a grade. I have a digital temp gauge and started to notice that the temp was all over the place. It would start climbing rapidly from 190 to 230 and the fan had a hell of time catching up.

I told the dealer of my issue. The test drove it. Head gaskets were shot. I now have stock gasket's and ARP studs. My temp issues are gone. The temp increases are very gradual going up and cools down fast.

If you are blowing coolant and have erratic Engine temps.....Chances are your gaskets are done.

~Brad