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Manuf. oil specs question


Top Banana
Cut to it- GM power steering fluid spec for early 90's systems- i poured 2 so far thru paint filter timed & thickness/drip time varies greatly.
I take it the spec has nothing to do with thickness?
Synthetics will flow better than conventionals when cold, even with the same rating. This might account for some of what you are seeing. I believe you may use any kind of Dexron III or better for that application. I use synthetic oils exclusively now because they are far superior in cold operation and in longevity. I put Dexron VI full synthetic in my '86 Chevy PU PS system and transmission. That fluid is definitely thinner when cold, but is actually more shear stable and has slightly higher viscosity than the old Dexron at high temperatures.


Paint Fanatic
Staff member
Not sure why your doing this but a zhan cup #2 would give you more reliable readings.
Its been ""many many years"" but back in 80's the auto trans fluids were about 10 weight and that was used in power steering except for some British cars.
Like crash, I use synthetic trans fluid in my old car power steering units.
Its been a long time and things change.


Top Banana
Jc- i'm checking oil not filters. Used filters to slow it down easy way.
Crash- one is synthetic, going out later for another brand synth with higher hot/cold numbers, meets same gm spec.

Tried thicker dino first, sounded a touch quieter then old dirty stuff but fresh of anything might've helped.
Yesterday tried synthetic thin stuff, possibly noisier.
Later or tomorrow i'll get another major brand synth & try.
I can't get to hoses to flush so i suck reserve dry, fill, drive turn lock to lock, repeat oil change.
90 degrees by noon till a cool winter 70's down here so winter fluids need not apply.

Edit- Thanks jc & b for cup tip
Just keep in mind that the stuff that seems thicker during your cold tests could very likely be thinner than what you compared it to when hot. If there is excess noise, there is probably a failure that needs to be addressed, imo, most often a faulty pump (but I am sure you know that).

The only real way to test these fluids is at operating temps.


Top Banana
Thanks crash & for previous post.
Yes i drive till hot, ac on, feels like 100 in shade right now.
Every utube comparison i found is putting in freezer & then pour down a strip.
I need to tell people to also heat to 212F for pour test too!

To be continued, had to remove door clad just now, saw metal clips let go.
Pool calling.


Top Banana
Ordered what a ad elsewhere lists as #1, description hole size is #2, either way I want it for hot oil so we shall see.
Made this when I wanted to try house paint with same vis as uvc. Worked perfect, hit record on ipad, poured, played back slow using finger/timeline. IMG_1341.jpg IMG_1342.jpg IMG_1343.jpg
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