I just completed a 1000 mile UK-Tuscany trek with more trouble than I cared for. About 250 miles into trip I noticed that the oil pressure needle, usually right up at the peg, was moving down when I was backing off the throttle. I had been driving at speeds between 110-130km/h. I pulled over and saw that the lower part of the engine was full of oil. Level was at minimum. Oil was dripping along the length of the car. I added about 2L of mineral oil that I had in the trunk and continued another 150 miles, slower than before, checking the level every 50km. At the overnight stop I checked all oil circuit connections and found that the middle bolt on top of the oil filter housing could be tightened half a turn. (Sorry, no photos). I continued the trip going around 100km/h checking oil level every 100km with minimal loss. Not sure of what was the source of that oil loss, but am suspecting that I might have piston ring issues and oil escaped from the dipstick breather. The engine was completely rebuilt at RSP Motorsports in Ontario, Canada, run in on a Dyno for 150km and then had an oil change to LIQUI MOLY МoS2, Leichtlauf Oil 10W-40, which is a semi-synthetic. I changed the oil/filter (same oil) last year after a 1000 mile trip. Engine runs really well, pulls nicely and is quiet and has done about 3000miles since rebuild. What are your thoughts and what should I be doing to diagnose/fix the issue? I will be changing oil/filter today to 20W-50 mineral oil, since right now I have a weird mix in the engine after topping up the oil.
My just rebuilt speedo is also acting up, oscillating slightly. I did not change the cable after the speedo rebuild and it is making some whirring sounds. The same shop (German, specialized in instrument rebuilding and highly recommended by a friend) also rebuilt my tach and it is rock solid, so I suspect the cable rather than a bad speedo rebuild. So a cable replacement is next. I checked and did not find step-by-step instruction on the forum. Can someone please point me in the right direction and also provide a good source for a replacement cable? Car is in Italy at the moment.
Thank you for any help/suggestions.