Looking to see if anyone has any ideas as to where some oil is going in my RB.. My mostly stock, recently refreshed, RB25DET is losing oil (1 litre in the past couple months of daily driving). It isn't leaking externally or smoking or have any indications that it might be burning oil. The oil pressure is a bit lower when warm and cruising at 70mph compared to before (~3kg/cm^2 on the oh so accurate stock gauge in my R33, used to be 4) and the idle pressure is slightly lower too, but this could be completely wrong knowing the pressure sender issues on RBs. The oil pump was replaced earlier this year with a new OEM one and plenty of the seals in the block were replaced too so no external leaks. Also I don't think valve stems could do it as it isn't smoking.. Any suggestions highly appreciated.
Rear main seal pinched and leaking? Oil would be all through the inside of the bell housing then. Otherwise front crank pulley seal? Cam cover gaskets?
I might be a little late on this topic but I'll just chalk it up to me just signing up on the forum 10 minutes ago. So my question is are you losing oil or are you having oil starvation problems? I've been doing some research and found that the RB25 is notorious for the heads collecting the oil and staving the rest of the motor. There is a fix for it though. You would have to install an oil drain valve on the back side of the head and have it return to the sump. They have kits for this but they are sorta pricey and maybe only a small handful of places in the U.S. that make them. Otherwise you would have to order from out of country. I hope this helps. I'm in the same boat myself atm. Good Luck!!
couldnt you just add extra oil over the full mark on the dipstick ? then it will still have oil in the sump even if there is too much in the head ? every RB ive seen imported has the oil over the Full mark .
