mostron8

So, I'm changing the oil today, just rolled over 600 miles. Used Pennzoil 5W20. But, I went and filled the oil up a little bit more than the full mark. I started it, let it run for a sec, shut it off, let it cool for a sec and it dropped a bit, but still a bit above the full line. My question is, should I be worried about this? Should I drain it all and start over? Is there and easier way to drain a teeny bit? I think I know the answers, but I figured I'd post here first and ask the gurus.

-Nathan

MaRX8

How about a Turkey baster? You could suck some of it out, a little at a time.

neit_jnf

What's so bad about a little overfill?

mostron8

Sorry...let me define: approx 0.3 quart.

RX-Nut

Hmm.. you changed it at 600.. my dealer says come in at 3000 as it's on them.

Dang guess I better look at the manual..

vudoodoodoo

Just drain it a little. No biggie.
You can run the car and let it circulate though the oil cooler(s) and then drain it and refill.

wakeech

...OR you could drive it really hard and fast for a little while (now that it's getting to the end of the break in cycle...for the betterment of the car!! DO IT!!) and just burn it off

blizz81

Check it next time before you go out to make sure the engine is fully cooled. If it's still a l'il over I'm w/wakeech

mostron8

Well...I just changed at 600 because I'm **** about my engine like that. I want no metal particulates circulating in my oil after a break in, so I changed it. It's easy enough in the 8. Had to jack up the drivers side to make enough clearance for my oil bucket to slide underneath.

Lensman

It might not be the case with the Renesis but with my current piston engine I shouldn't overfill the sump because the excess oil pressure can blow the gaskets. It's not likely but it CAN happen.

mostron8

Yes, that's what I'm wondering. How does this affect the enigne? I haven't noticed any increase in oil pressure (by looking at the gauge) so I'm not too worried. More curious as to what an overfill will do to a rotary engine.

-Nathan

eccles

The gauge won't tell you diddly, because it's basically a glorified idiot light - it will never move from its "normal" position unless you have a total lack of pressure.

As far as overfilling, I wouldn't be concerned about an extra .3qt. The Rotary is basically dry sumped - the sump is a separate chamber beneath the rotor housings and sandwich plates, and there is no crank slopping around in it. A little overage won't hurt.

Racer X-8

Is the .3 qt. in the new oil filter? I know how it's mounted upside down, but don't know if it actually drains when the engine is off. The nail hole trick to remove it w/out making a mess tells me that it doesn't drain.

mostron8

I don't think so. I drove it around the block to give it a chance to completely circulate within the system. Got home, same approx .3 qt overfill.

What's the nail hole trick? Never heard of it?

-Nathan

daedelgt

Wait, the oil pressure guage on the 8 doesn't have actual pressure readings?

Racer X-8

I read about it somewhere in this forum. Just before removing an old filter for replacement, put a hole in its outer shell. That lets all the oil drain out of it for dripless (almost) removal.
Some people are complaining that doing that will be hard cuz of where it is. I'm thinking some long pointy thing like a shishkabob stick might come in handy. Dunno. I was gonna suggest putting the hole in the new one first, before installing it, but some idiot might actually try it.:D

mostron8

Well, it doesn't tell you the pressure in PSI, but is shows L to H.

eccles

Nope, it's a "fake" gauge. It's operated by a switch, not an analog sender, and serves simply to indicate the presenceof any pressure over the cutoff value of the switch.

Perhaps someone with access to Mazda's internal literature can tell us what that pressure is, but I suspect it ain't that high - maybe 10psi.

That's why the "gauge" springs instantly to a little over 1/2 scale the moment the engine fires, and never wavers from that point until the engine is turned off or stalled.

Early Miatas had a fully-functional gauge, but apparently Mazda was getting too many service complaints from earlier model owners who were concerned that the gauge was fluctuating under normal driving conditions, so they changed to a similar "binary" gauge in about 1995.

Because of the idiots, we now get an "idiot gauge."

neit_jnf

How do you know this? Is it a real fact?

daedelgt

Interesting. I know the FD's guage works well. When I'm low on oil I usually read 5-10 PSI lower.

Sputnik

Mazda (and several other manufacturers) normally do this nowadays. Mazda does this on the Miatas, they did this on the pre-production RX8s, and we haven't heard that they've changed this on the production cars.

Fortunately, the gauge is there instead of an idiot light. So those of us who want a real pressure gauge can easily set it up without resulting to an a-pillar gauge mount, or other major modification. It might not be the same, but for the Miata, all we have to do is install a real pressure sender with an adapter, and re-align the needle on the gauge. We still don't have a number value, but the important thing is to have a general idea of where it's at.

---jps

mostron8

So where do we get this adapter kit, etc. I'd like to investigate installing this. I had no idea it was a stupid binary gauge.

Sputnik

Well, the thing is, we don't know if the same mod will work for the RX8. It might be a case of the sensors being tied directly to the ECU, and the ECU driving the gauges, as opposed to the sensor directly driving the gauge. We'll have to see once someone gets a good look at the full shop manual.

---jps