Originally Posted By: Snagglefoot
Originally Posted By: SirTanon
My next oil change is due around mid-late July, and since August is usually our hottest month, with many days over 115 and even up in the 120 range, I'm probably going to fill with either straight T5 10W-30, or T4 15W-40 topped with my last quart of PUP 5w20.
Do you still have your catalytic converter? The T4 and T5 are not SN rated as far as I know and have copious amounts of Zinc (bad for converters). Maybe you want to pick up a 0w40 OR 5w40 with a AECA 3/4 and a SN rating such as Castrol. If you've been running T4 and T5 already, or its a diesel, please disregard this note.
The jug of T5 that I have - A 2.5 gallon jug from a year or two ago - is at least SM rated. Not sure if it's SN - I'll have to verify this when I get home. Regardless, SM classification states "For 2010 and older automotive engines", and my Fusion is a 2010 built in 2009, so I'm fine there.
As far as the catalytic converters and the concern over Zinc goes, this is only a problem if the oil is burning and reaching the converter - an issue that my car does not have. Over a 7,500 mile OCI, the oil level does not drop by any visibly noticeable amount, so for all practical purposes, my engine does not burn any oil, and so the zinc levels are not a concern.
Originally Posted By: mx5miata
Wouldn't a good 5w40 SYNTHETIC set you straight?
Perhaps, but I have a rather large stash already, and all the oils in it are at least rated SM, which works for my 2010 Fusion. The Ford-recommended Motorcraft oil is a synthetic-blend, so T5, which is also a synth blend, at least meets that level. Heck, T4, while still being 'conventional' is stout enough, I'd say it will hold up and protect as well.. and probably contains a percentage of 'synthetic' stock anyways.
Because of the heat, the only really pertinent number (for the most part) is the one before the "W", since it never gets
below 90 in the summer. I know about VIIs in oils with a wide spread (5W-40, 5W-50, etc..) but again with the heat here, and my extended highway driving, I suspect most of it is going to shear down over time.. I figure the HD oils might help to overcome that somewhat.