>>>Dick, I am not certain if the SAE 30 was recommended for these >>>temperatures or simply considered a possible/allowable alternative. I >>>think its the second. Well, perhaps you need to take another look in your FSM. I did quote the manual verbatim, and I see no other way to interpret what they say. And, I quote again: SAE 30 AND SAE 40 ARE RECOMMENDED [then it goes on to discuss multigrade oils, which are also permitted, if 20W40 or 20W50 is used, with a special "high performance" additive (STP?). The capitalization for emphasis is theirs. I do agree modern multiweights have been improved, but I believe the improvements have been primarily in anti-foaming, contaminant suspension and anti-char properties. These same improvements have also been made in the single weight oils, as long as you are careful to stick to SH - SJ spec oils. I think we should cut this off here - I'm not going to change my mind, and I doubt I'll change yours either. I'll stick with my single grade oils in my old cars, and use 10W30 in my modern car, instead of the specified 5W30, which is thin as water at operating temperatures - I just don't trust it to give me 340,000 miles, which is what I got out of my last new vehicle. (1985 Chevy PU - - it was totaled [while parked] at that point, with still no sign of deterioration in the engine - I never ran anything but SAE30W in that one either!) I do use 15W40 in my new truck, a diesel, and as you note, it is specifically required - and has further restrictions on characteristics also. Dick Benjamin ----------------- http://www.imperialclub.com ----------------- This message was sent to you by the Imperial Mailing List. Please reply to mailing-list@xxxxxxxxxxxxxxxx and your response will be shared with everyone. Private messages (and attachments) for the Administrators should be sent to webmaster@xxxxxxxxxxxxxxxx To UN-SUBSCRIBE, go to http://imperialclub.com/unsubscribe.htm