Information that I have been given from lubrication engineers that I used to work with. Fully synthetic oils do not transfer heat as well as mineral oils, so your oil temperature will be lower. This means that the oil is not cooling the engine as well as it should. In industry they do not use synthetic oils for cooling applications. eg. large transformers This is not my opinion, but what I was told by guys that went to university to learn about oils and greases. (They also told me not to steal the very expensive molybdenum disulphide grease from work for my CVs as it would dry out because it wouldn't be worked hard enough)
Hi guys, hopefully this is within topic but a colleague who has rebuilt other motors (not VWs) suggested that the first oil after the rebuild should be lighter (like a 10W-50) to get a good flow around the block, get everything lubricated, run a few 100k's gently for the run in and lubrication and then drop that oil (as you would anyway) for the post run-in oil change. Has anyone done that ... or think it would be worth doing ... on a 1.8/2l Type 4 motor?
I ran 'break in' oil on my engine (the one discussed in this thread. Did not make a difference in oil pressure. The issue seems to have been related to case / bearing clearance, as once the case was replaced, the problem was gone. At a guess, I think the problem was with the machine shop. I reckon that the engine builder took for granted that the machine shop's measurements were accurate and slapped it all together without checking clearances.
If I recall correctly from some comments by 1500king and probably others full zinc mineral oil was the best. I don’t know what that really means but something to do with heat transfer and correct lubrication for the tappets. I always ran mineral oil in my kombi and Nats beetle The SAABs get full synthetic. The golfV gets whatever is cheap because it’s POS and deserves to die properly so I can justify replaceing it.
For the pain it’s caused me it deserves a slow painful death lol.. also gives me more time to find a suitable replacement - Nat is regretting selling her Beetle it was more reliable than the golf.
And why did Nat sell the family beetle project? I’m guessing mod cons, like aircon, power steering, central locking, etc......
what was the out come from this post? I'm recently having the excact same problem with a freshly re built engine