Hi, I have a 1988 1700B with a perkins diesel and looking to do an oil change. The manual says 20w20 oil...any idea on where to find this or what it was replaced by. Thanks....
Hmm can only offer what I have seen change over the years in the oil world. Not looking to start an oil war that happens on many sites, I would say in the end your going to wind up with either 15w-40 or 10w-40, 5w-40 multi-viscosity . The main important factor is the API CI-4 Plus/CH-4/SL/SJ certification for diesel engines. The 20w does not refer to "weight" rather the winter or cold viscosity rating. The 20 would mean a very thin oil when hot, and just using a regular car rated 5w-20 would most likely result in too thin of a oil film layer. Basically, up until 2017 there will not be diesel rated thinner oil without setting u back a small fortune (ie diesels are doing what car manuf started doing going to a real thin layer light viscosity to improve mileage). That's what I've seen and I have to go down to 5w-40 for winter (or heat that oil) or its like sludge in winter. There are quite a few JCB guys on here and should be able to chime in on what they have switched over to.