Originally Posted By: addyguy
Straight-70 weight is the thickest motor oil grade I've ever heard of.
Even though a 25W-70 or 40W-70 and a straight-70 are the same at operating temperature; a straight-70 would be thicker at lower temps, and therefore I think it wins as "The Thickest Motor Oil" you can get.....
For fun, I would LOVE to get my hands on some 25W-70 or 40W-70 and do a short run during the hottest part of the summer, just to see how the car would run. Penright does sell oils in Canada, and I think these two oils are offered....hmmm....
Im tempted to put that 40W-70 in in July out here (or August!!!) When it is a nice consistent steamy humid 90 degrees and better.
Im only slightly scared at this?
One thing is for sure.. it makes 20W-50 - even the Valvoline stuff - look like GC.
Now, here is another question.. will an old 10W-40 engine SURVIVE 10W-40? (Think old, old Monster V8 fro, a time of real engines that have big huge blocks and MASSIVE Displacement.. 400ci or better.)
I thought if you put Lucas in it (Straight 80-wt, looks like pancake syrup?) it would also be almost that thick.
Hmmmmmmmm..............