96 GLT should be a turbo engine. If so, doesn't have a flame trap. Oil cap seals get brittle with age. Visit the dealer with a buck or two and replace it. EEEE on radio display indicates wrong code was entered. If the radio was replaced,(likely) most dealers don't update the Volvo database. To get the proper code you'll have to have the radio part #, serial #, and model. Push the two tabs on either side of the radio, they will pop out. pull on the tabs and the radio slodes out. Write down the part and serial numbers. Model is on front of radio, example, SC 816. Give this info to dealer and they can get the right code. If wrong code is entered 3 times, radio locks out, display reads "off" To unlock, the key must be in the accessory position, and radio turned on for 2 hours. Then the display will read "code" and you get 3 new tries. One thing you will want to check is the positive battery cable. They are known for bad crimp on the terminal end at battery. Using a digital volt meter, conect between battery terminal on back of alternator, and batt positive at the battery. Start the engine, turn on lights and blower, and read meter. It should read no more than about .1 volt. If its higher than that, you can repair by removing the battery, remove smaller wires vrom batt terminal, peel back or cut off the rubber sleeve that covers where the cable enters the terminal, heat the terminal with a propane torch and wick some solder down around the cable and into the terminal. A lot easier than replaceing the cable. Wrap with electrical tape and reassemble.

I've noted the same oil collection in my V70AWD. It seems like the oil cap always seeps. I fixed the problem by simply turning over the oil cap gasket. No more seepage, no more collecting under the cover!

I just changed my plugs last weekend and saw the same oil pooling under the cover. I think it's just overspill from filling the oil. The only other way I think oil could get there would be if the crankcase were under pressure and oil was being pushed past the oil cap gasket. Did you clean your flame trap? Don't know anything about radio codes.