CBRF3
Full Access Member
nice idea but a good external trans cooler is better because it can cool the fluid lower than the engine coolant temp making the fluid a bit more thicker ( aka more efficient and need less GPM flow ) to push the fan motor easier and with less issues of fluid breakdown keep in mind also as you heat hydraulic fluid it expands and your reservior for the power steering pump is limited so keeping that thermal expansion minimal is key. I would use both but would use a sealed high pressure trans cooler infront of radiator pre fan motor then after dump into the radiator trans cooler this way when are under heavy heat dump your actually adding cooling capacity to your radiator not adding more load to it.Every rear engine powered school bus uses a hydraulic fan like that, as well as most pusher rv/motorhomes.
I'd consider them semi-reliable. Less reliable then a mechanical fan in a front engine vehicle, but that's because in a rear engine setting the fan is used a lot more because of no natural forced air going through the radiator. With a front engine, you have a lot of air going through the radiator at speed, so a mechanical fan with a silicone clutch or an electric clutch is rarely used, and their failures are less apparent.
I've got a dt408 swap in my head and was going to use hydraulic fan over an electric one. And as said earlier, a significant power steering cooler is necessary as well. A loop on the crossmember isn't going to cut it. My thoughts were to use a manual behind the dt, and then use the ATF cooler on the existing radiator as my power steering cooler.
I myself run my fuel thru the radiator trans cooler pre injection pump to avoid thermal shock on the injection pump and I return my fuel from the injectors / injection pump pre filter ( factory filter head is removed and deleted altogether I use a large baldwin filter just under my bed below a large in bed fuel tank ) this way I get a heating effect to oncoming fuel and defeat filter plugging and such I also use a engine oil bypass filtration system I built / designed ( sub 5 micron ) and then after that goes into a large trans cooler this helps keep my engine oil temps in the good range when towing heavy / hard.
Last edited: