ok i just changed my oil and tranny fluid.

went inside rested, then i went outside warmed up the car, except it didnt warm up but it did have reall good oil pressure. i let it sit for about 10 minutes and it only made it to the first line on the temp gauge, so i decided to just go out for a drive anyways.

well i drove around my neighborhood and a few friend's and then as i turned onto a main road i i slowed to a stop then i floored it through first, second, and third.

it felt really fast(as in faster than it has ever felt before)
then i put it into neutral to coast down to a better speed, and the oil pressure dropped to about nothing @ idle i also looked at the temp gauge at this point and it was STILL at the first tack mark

does anyone know waht is up with my car? i know all the gauges are on and working correctly, so...

84 GSL-SE

 

so no one knows/doesnt have any ideas?

 

Faulty senders? Those things are getting pretty old, maybe they got jostled, and decided to take a flying leap? Obviously you have oil pressure still, or your car would be dead on the side of the road.

 

Oil temperature and pressure gauges are not very accurate in these cars (84SE from my experience).

What you may have found is that when you changed the oil, it restored some of the cooling properties that had been burned off of the older, dirty oil. When this happens, the oil temperature and engine temperature (water) will go down, and that's to be expected. BTW, you know that your temp gauge on the dash shows water temp, and not oil temp, right?

Anyway, when the oi system is running correctly, and with a new Pressure Sender unit installed, you should see about 35psi at idle and about 70psi at cruising speeds - engine RPM over about 3k. If you get wide swings in the pressure gauge, it could be that your pressure sending unit is going out, or your oil is sloshing around a lot in there. Oil Pumps are almost rock solid peformers, and I've NEVER heard of one going out. Pressure regulators do go out from time to time, but usually this results in high oil pressure, not low.

Could also be that during the oil change, you got some air bubbles in the oil channels that collected around the pressure sending unit - resulting in what looked like zero pressure under idle. Should go away with time.

The oiling system on a rotary is pretty reliable - it's because the engine must have oil pressure to run for more than about 10-15 minutes under load. Oil provides THAT MUCH cooling effect for our engines.

 

yes i know that it shows coolant temp, and that with the fresh oil the cooling properties are better, but it shouldnt be this cold(the first mark that is even on the gauge is where it stays)

it doesnt go up to 70psi until 4-4500 rpms on the oil pressure. it is probably about 10-15 psi @ idle

it *was* at around 30-35 psi at idle for the first few minutes though, just not anymore

 

Oil viscosity changes with temperature. Cold oil is thicker, thereby building more pressure, and registering on the gauge appropriately.

As the oil heats up, it gets thinner, so expect that your oil pressure will change from cold to hot engine temps.

If your water temp gauge seems to be showing low - I'd suggest DE-focusing on the oil change issue, and start looking at the water coolant system. Could be that your fan clutch has gone out causing the fan to spin at full speed all the time, resulting in TOO much cooling air past the radiator and a resulting low engine coolant temperature. Could also be that your thermostat is stuck open, allowing more coolant to flow through the block and cool the engine more than before.

Try breaking the analysis down from looking at BOTH oil and water temps, and look at each one individually to see if it's something going right, or going wrong.