ok i changed my oil and am now running castrol gtx non synthetic 20w-50. lately my oil pressure hasnt been at 60 lbs when cruising at 60 m.p.h. but before when i had 10w-40 in it it would read exactly 60 on my gauge. is this normal? the car idles perfect at 30 lbs. of oil presure. the car is a 88 gxl with only 68,000 iles on it. would the temperatute of the air change this when i put the 20w-50 castrol oil in it and change? lately its been about 70 degrees outside.thanks for the help do i need this heavy of a oil for the car?thanks for the help.









waste ricers,all of them!!!!!!!!!

 

First of all, at this time of the year it could be a little soon to use 20w50 but that's not a problem anyway. If you installed an aftermarket oil filter, it could sometimes result in a loss of pressure while the oil is not warm enough. This is probably due to the oil going through the bypass valve in the filter instead of going through the filter itself. In Mazda oil filter the bypass valve is specially calibrated to sustain more pressure before opening. I have seen the difference when I've tried aftermarket filters the first year.



Yes, it's good for engine to use 20w50 in summer. But I would not worry about it if I were you.

 

i just wany my 1988 GXL rx-7 with 68,000 miles to last forever!!!!!!!!1











waste ricers,all of them!

 

I personally think that the oil pressure sender should have been installed between the oil filter and the rest of the system so we would read on the gauge the real pressure in the motor. If the oil filter is clogged, the oil will go through the bypass in the filter and you probably won't noticed it on the gauge, and the pressure on the other side of the filter (so in engine) would probably be alot lower than what you actually read on the gauge even if not clogged. So why do they always install gauges before filter? If someone has the answer let me know. Would it be to sell more engines or what? ??? It's like testing the voltage at the battery to see if the electricity is going to the radio for exemple! :dontgetit:

 

I've got an original owners manual.... says you should be running between 43 and 86 psi @ 3000 rpm.....



I'm getting worried about my pressure personally.... getting around 28 psi @ idle, 36 psi @ 3000rpm and only hitting 43 psi when i'm at around 4000rpm....



any idea if this coulda been caused by overheating? i took my car on a long uphill burst on a warn day and it didn't enjoy it too much.... i know rotaries hate the heat, it wasn't intentional ???

 

Are we talking about the dashboard gauge, or a more precise instrument to get the pressure readings? My TII had zero oil pressure when I first got it running, which concerned me plenty until I heard that the sending units go south on these cars all the time. I replaced the sending unit and my pressure is fine. :smilewinkgrin:

 

that was my next question.... mine has 75K and runs perfect but the damn stock guage tells me I have around 10-15psi at idle.



That's a good tip about using the OE Mazda filters. I'll pick one up for the next change. Hopefully its not $20 like the friggin 5 cent bolt I had to buy from them. :madgo:

 

If you still have overheating problems, first replace the thermostat (use genuine thermostat), the temperature should be stable with the genuine thermostat even if you climb up a hill.



The oil has probably been degraded by overheating so changing the oil and filter is a good thing too, use 10w40 or 20w50 depending of the season. I think the autumn is coming by in your area so you may need 10w40.



I figured out your gauge was reading ok before that overheating thing so be sure of your gauge.

 

Sorry, this is a post error!

 

As I said it's not filter itself that is the problem with aftermarket but the bypass valve in this filter.



As for the price, since they've installed the same in mazda 323, it has the effect of dropping down the price (market law). It's almost the same price as an aftermarket.