Pennzoil 5w-50 synth: Johnny? Anyone?

Messages
622
Location
42.4N 85.7W
Has ANYONE seen this oil on a shelf or know where I can get some via the web? I can't find it ANYWHERE. I know, I know "That's too much of a spread, blah, blah, blah." I'm not looking for extended drains (2000 miles MAX) and it's for a peculiar application. My mother-in-law has a '90 Miata that for the first 10 mins or so has PLENTY of oil pressure (I think it's even exceeding a bypass valve point, cuz when revving, pressure will build to a point, then QUICKLY drop 10-15 psi, then hold.) But, after engine and oil are completely warm, barely makes 20psi @ 2k RPMS. Any help on finding this oil (or a better solution for my problem!) greatly appreciated. And no, I'm not interested in trying the widely available Castrol 5w-50 except as a last resort as I think they're single handedly responsible for retailers charging $4/qt for group III. TIA, Dave
 
Messages
2,768
Location
Tn
What oil are you experiencing this problem with??? Oil flow is of paramount impotance rather than actual pressure. I don't know this engine, but it may not be a problem. I can't imagine that anything other than a 10W-30 would be appropriate for yor 1990 model. Sorry, but I don't think that any 50 wt. would be right for a Miata. 40 or 50 wt. [SPAZ!]
 
Messages
2,602
Location
The Tropics of Antartica
It sounds like the oil pump is worn . With the Miata it is usually due to using too thick an oil during very cold weather or too thick all the time . These engines run over 300k with 30wt and make ugly noises with 40wts below 30F ,ask me how I know . First I would screw in a manual pressure gauge and make certain it is not the sending unit . The gauge looks like it's manual but it's not . If lucky it's the sender , a cheap fix . Just putting thicker oil in it will not eliminate the sending unit as a possible problem
 
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