How many quarts of oil does a 1994 buick regal hold

If it is a stock '85 Buick Regal (which I doubt), it would be about five quarts, but if the motor came out of a truck it could be six quarts. Look up the serial number and find out what you have.

It depends on how much oil and how long the engine ran if any.
If you put in 2 quarts too much but did not start the engine, no worries.
if you put in 2 quarts too much and drove it for 50 miles, you could have damaged some seals and they may start leaking. Odds are you did not damage anything internally.

I'm not sure I am following your problem.
A transmission holds 10-15 quarts including the torque converter. When you drain the fluid you are changing about 4 quarts of the full amount.
Once you fill the transmission to the full mark on the dipstick, you should not be adding more fluid unless there is a leak. Or if the vac modulator is damaged and allowing fluid to be pulled into the engine. The fluid is checked with the engine running in park.

It has a paper gasket behind it. The oil pressure switch could be leaking too.

can you give more detail did it start to run rough,how much oil is on the dip stick,does it turn over,????

First off, When you say the wrong oil in, do you mean a quart of the wrong weight of oil such as 5w30 and the vehicle calls for 10W30? or do you mean you used synthetic oil mixed in conventional oil. If you added one can or less of the wrong weight oil, then I probably wouldn't worry about it until your next oil change. If you added synthetic oil into conventional oil then do the following.

You need to get under the car and look for the oil pan which should be directly below your motor. Put a large container that would hold at least 8 quarts of oil under the oil pan and use a wrench and remove the drain plug allowing all of the oil to drain into the pan. Once all drained, you might as well change the oil filter and add fresh oil to your vehicle. If you have never done it before, it is fairly simple in the regal but buy the oil filter so you know what your looking for. I believe the filter is on the front of your motor. Make sure you put a ring of oil on the seal of the new filter before installing and then spin it clockwise to put it on. Lastly re-insert the drain plug and fill the motor with 4 quarts of oil(expecting to add total of 5 quarts). Start the car for about 30 seconds and shut it off and check the oil level. if low add the 5th quart. Check under the car for any oil leaks. Not a hard fix. Good luck.

More than likely (and we will hope) it is the oil sending unit. In comparison it is a very cheap and quick fix to replacing the oil pump. Auto Zone has a pretty good componet location section that has tips for replacement if you cant find the sending unit or the oil pump. Try that first it may save you a lot of work.

Hello
Yiu can have a bad oil presher switch,, or low on oil..or bad motor
RD

filter is on the passenger side of the motor just behind and below the power steering pump if you look at the motor from that side you will see it

I am assuming you have the 200 4R, I just replaced my tranny fluid on my 87 GN, took about 6.4 quarts. I also have an external tranny cooler and let the tranny drain for about a week.

I would start with 4 quarts and start her up, dont drive anywhere. Keep adding and checking while the car warms up. Every now and then get in and shift through the gears, pausing in each one a few times, ALL GEARS. When the fluid level refisters on the dipstick, take the car around the block slowly at first then fast enough to shift into 2nd, depending on factors 3rd or 4th. Head home and leave engine running, check fluid again and adjust accordingly.