D17 IV Oil fill breather?

My D17 IV has oil leak out of the oil breather/cap when under load.  It doesn't seem to have excessive blow-by.  Will a new cap solve the problem at $70 or is there a better way of venting the crankcase?  Thanks!  Craig

I'm not discounting the possibility of an engine overhaul, but for years I've always added a breather hose like bigger tractors have, to totally eliminate the oily mess that oftentimes soaks spark plug wires it gets so bad. To do so, first throw away the old breather cap....second, you need to weld/braze a short 3/8" pipe nipple to the neck of the old breather tube 2 inches down from the top and aimed at the battery and a little bit uphill so oil doesn't want to run out of it. Then attach a piece of 5/8" heater hose (about 36" long) to the nipple and run the hose downwards towards the starter and between the starter drive and the side frame. Before welding the nipple to the valve cover tube you have to drill a hole in the tube first, so be sure of proper nipple placement beforte you drill the hole. Finally, obtain a rubber plug to block the end of the tube.....one from a 1978 or newer F2 diesel combine fits very nicely and I think your local auto parts store may have something from a GM car that would also work. The key is to be sure to have the nipple/hose running a bit uphill to keep the oil where it belongs. With this little improvement the engine will now stay dry from oil coming from the breather area.