When I purchased my car the oil pressure would always be at 80psi whether it was cold or warm. Before the first time I took it to the strip, I did a complete oil change including filter. Ever since then, My oil pressure drops to around 55psi warm. This was literally like 15 minutes after the change as I went to gas up afterwards and noticed that the oil gauge on my tach was lighting up when at idle. Between the factory sensor, autometer oil pressure sensor and the tach sensor they all show reduced oil pressure. Is there something I can do to bring the pressure up or is this impending engine failure? Btw, The pressure does shoot back up to 80+ when a load is applied.

 

hmmmm I may be way off base, but for some reason I think both of my FB's operate normally around 55-60 psi I think I would become very concerned if my oil pressure was a steady 80 psi. This sounds very normal your idle since you have a mechanical oil pump, will yield the lowest oil pressure. As load is applied the pump is driven faster and the pressure will increase. I am not in my car right now so I cant tell you for sure if that is what normal oil pressure is.
Chris

 

I don't trust factory oil pressure gauges in rotaries at all!!! Don't matter if it is FB, FC or FD I just plain don't trust them...

 

Did you change oil weight, or type, i.e. dino vs syn, or a different brand of filter?

 

I don't know what weight oil was in it before and as for the filter, I just used a replacement filter(purolator). I had thought about that also but could a different weight make a 25-30psi difference?

 

. Install a mechanical gauge thru the rear banjo bolt. that will give you a much more accurate reading than electrical gauges.

 

I think your guage must be off, it sounds kinda fishy.... I would consider testing the sending unit.

 

change your oil again and put in 20/50 your oil pressure will go backup

 

I don't know where you're getting "80psi" and "50psi" but my gauge is at like 2kg/cm2 at idle, and 4kg/cm2 under any sort of load, or even just rpms higher than 1500.

Sounds like normal operation to me. Maybe there was just something in there before that was causing constantly high oil pressure. Did it have a FRAM oil filter? Those have been known to sometimes cause problems with high oil pressure.

Purolator make good filters. I don't run anything other than the PureONE PL14459 on my car, and recommend the same for anyone else.

I use 10w30, as per the factory manual. Some have used 20w50 with some success, but I prefer to just stick with 10w30.

IMHO, you don't want constantly high oil pressure, because that means that chances are it's kicking the bypass and not actually going through your filter under load if you're at 80psi at idle.

Jon

 

Usually it's a crappy gauge. Hook up a mechanical one. I did and my oil pressure was great. Barley registered on the stock gauge. Even after a new sending unit cleaned wires etc...

 

I do have a mechanical gauge in the car, That's how I got the 80psi reading. I also have an aftermarket autometer tach with a oil pressure light and it comes on now at idle also when it's warm. I think I'm going to get the oem filter as I think that's what was on it before and see what happens.

One other thing, I have tried changing the oil with 20-50 before and it didn't make a difference so I'm wondering if the old oil filter was just being restrictive maybe?

 

There is nothing wrong with FRAM. I have been using it for 20 years in all my RX's with no problem.

 

At what psi does the light come on on the Autometer gauge? FSM specs for oil pressure are 64-79 psi @ 3000 rpm and 12.8-38.4 at idle. If you are within those ranges and have a stock opr, you're good.

 

Like others have said, your first step in diagnosis is to install a oil pressure master gauge. As far as problems with oil pressure go (this is probally mostly related to pisstons, but can be carried across) it can be caused by high clearances in the oil pump, no oil pump drive shaft (no pressure at any rpms), or any internal oil leak. What comes to mind is the top middle oil gallery plug on GMC C and K trucks, it pops out and bleeds oil out into the front cover. This in return makes it so that the oil pump cannot build up enough pressure resulting in the low pressure gauge results...

I hope this is some what helpful, I am a rotary guy at heart, but most of my diagnosis i've done has been on conventional vehicles. (BTW 1900 posts, do I get an award?)

 

Fram is not suggested as there design is made to artificially increase the oil pressure and is not suggested to use. I recommend OEM only but WIX tends to have a nice filter inside them. If you want to know just cut one open you will find out really quick, what one is good.

Just to know do our first gens subdue to the front cover oring blowing and causing oil pressure loss like the S4's? Just wonder what our culprit is for low oil pressure.

The eight oil chosen for your car should be chosen upon the temperatures you live in. The only reason Mazda or any dealer suggests a light weight oil is to improve gas mileage.

 

Oh my. Don't you think it's about time to buy a new one? I've heard of hand me downs and sloppy seconds, but this is rediculous

 

Is this for the 13B? My oil pressure sits at about 50-55 at around 1k rpms. At 3000 rpms it will kick up to 80 and anything above that will be around 90psi or so.

 

lol.

 

If I were you, install a mechanical gauge. If it stil reads the same, then drop the pan and clean the by-pass in the front cover.

 

Figures were quoted from the 85 FSM. The only difference in the oil system specs between the 12A and 13B is the 13B has 1 more litre capacity than the 12A, even though both oil pans are rated at the same capacity.

If this was your first oil change, attribute the drop to a bad oil filter. I'm guessing that you bought the car modded and it may have a higher rated opr than stock.

 

With 55 psi when hot, I bet it is stock ROPR