mmmappajoos

Today I checked my oil pressure with a tester because it seems after idling my oil pressure drops to 10-15 and after about 20 mins of idling it read 25-30 psi, which I believe is normal. I’m debating whether to buy a new pressure sensor but I’m not sure if that’s what is exactly wrong because it only drops low after I drive and get to a stop. I don’t want to waste $90 getting a new sensor if that isn’t the problem.

My other issue is the smoke on startup, which I hear is normal but I realized today that the smoke doesn’t fully stop until about 20 minutes of idling. I use valvoline conv. 20w50 but my friend uses royal purple synth 10w40 in his 13b. I want to change to royal purple next next oil change. Could the high viscosity be the reason so much smoke is coming out? Or even causing the low oil pressure? Or is the smoke being caused by something totally different?

Sorry im asking so many questions, I’m still learning about rotaries and cars in general. Thanks in advance.

LongDuck

Oil pressure on a rotary is an interesting thing because the gauge would have you believe it's up there or down there, when in actuality, it's right where it needs to be. The oil pressure regulator is just above the oil pan and controls pressure being released by the oil just as it goes back into reserve. This functions well to keep oil flowing as it should during all RPMs and load conditions. Your sending unit is probably just fine, as most of us never bothered to hook a proper gauge up to the engine that's calibrated in PSI. As long as there's pressure AT ALL, you're probably just fine.

Now, to start the confusion on which engine oil is right... go with factory recommendations of conventional oil and viscosity. Mazda knew what they were doing with these engines, and while there have been improvements in oil technology, this engine - at the recommended change intervals - Can make little use of that technology, given that it sucks oil in through the intake to lubricate internal seals. You can spend a lot of $$$ on expensive oils, but would be $$$ ahead if you just changed it frequently and on schedule.

Welcome aboard, and keep reading and searching; lots of knowledgeable people on here who know how to keep these cars on the road,

j9fd3s

iTrader: (3)

if you have an 1986 or newer engine in the car, they have a little wax pellet in the crank that lowers oil pressure when its cold (thermal pellet, it speeds warm up by not spraying oil at the rotors when its cold)

so when the oil is cooler than about 65c, oil pressure is low, 15-20 psi idle, and 45-50 at 3000rpm. when the oil is warmer than this, the pellet closes and oil pressure comes up to 71psi at 3000rpm, and 25-30psi at idle.

the senders typically start getting flakey, and usually it will work fine when its cold, and then read low when its hot, and then at some point it just reads low all the time.

20 minutes of smoke is too much, basically a puff when you start it is ok more than that and something is not right