Quote:
Originally Posted by Laird Scooby
Some very good points there, one being you've rebuilt your engine and have only run it on synthetic cince new. The molecules in synthetic oils tend to be smaller than their mineral counterparts which can encourage leaks and/or burning on cars with engines that have never been rebuilt and run since new on mineral 20W50 say.
Also in the UK, the climate is much warmer (although at only about 3C here today it doesn't feel it!) so a 5Wxx multigrade is probably a bit too thin for us and again, would encourage leaks/burning.
There is also the argument on a car used mainly for short journeys that the condensation produced when started/while cold doesn't get burned off and contaminates the oil with an acidic mix so even with synthetic, it's probably wise to change the oil at least once a year, regardless of mileage.
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This is a useful discussion Dave. See above, I think 5W50 is a bit thin for the UK's climate - I shouldn't think it has been lower than -3C at all this winter.
My experience with the RB (as you know a B21a engine) and 20W50 mineral oil has been entirely positive. I know the B18e motor is a generation older, but the bottom ends are not all that dissimilar. I'll try 20W50 in Delores when I service it in the spring and see if it cures that last vestige of an oil leak (it was like the Torrey Canyon when Janet first bought it!).
Alan
PS. GAM has been running on 20W50 mineral oil for at least the period of David's ownership (it even came with a tin in the boot). I was planning to continue with the same.