Oil leaked out from the oil cap and the engine cover has a missing screw

The smoke is due to the leaking oil. there is a common problem where the oil hose that feeds the turbo leaks, and drips on exhaust. Open bonnet on cold engine and clean the rear part using degreaser of sprayer, start up the engine and let it idle while checking the rear . for better results i usually pull the car up on a white sheet of cardboard or paper so i can see where it drips or splutters the oil on top the paper. Turn off car about 10 minutes in and check under the car. the area where you see oil will tell you where to investigate further. Another common VW problem is the tappit cover gaskit that leaks from time to time. Remove plastic engine cover and have a look

Pretty much same answer as I gave for 87 Reliant see below. Shops have equipment to do cylinder leakage test. Do basic stuff below before doing last test ...cylinder leakage...which costs $$$.

Main point you are losing antifreeze/water. Check to see if you have water on the dipstick mixed in with oil. If so...probably a head gasket. If oil looks normal..... Before you do any test, tighten every hose connection. Check for loose connection into antifreeze reservoir. Sometimes there are small cracks on top which lets out pressure from cooling system. Look for leaks on water pump and radiator. Look at spot where you park the car...any liquid on floor? Not sure?..Put piece of cardboard under car to see if liquid is dripping from car. No leaks?...Start with a pressure test of the system. The pressure test is simply equipment that replace the radiator cap, a hand pump connected to it then air is pumped into cooling system. You watch the gauge to see if pressure is dropping. If pressure does not drop ..problem is most like a worn radiator pressure cap or stuck thermostat.. Do not buy the kind with button on cap to push down and release pressure. get original type and correct pressure. If overheating still, thermostat could be stuck, replace. Overheating of engine causes vapor lock, bubbles in fuel, which causes car to stall and kill. When cools off, fuel cools down and fuel will flow through fuel system again. Large amount of oil disappearing with overheating also sounds like head gasket or cracked head....Tighten up all bolts to gaskets, look for oil leaks on garage floor or driveway. If engine has developed a miss when running, pull plugs out and look for wet fouled plug. If antifreeze leaking into cylinder...plug tip will be whitish, if oil leaking into cylinder, grimey oil fouled. Do compression test on cylinder that is fouled and that will pinpoint if bad head gasket or cracked head. When doing compression test, radiator cap is removed and you listen to hear bubbles in radiator from the cylinder leaking into cooling system. 87 Reliant not worth pulling engine apart if head gasket or cracked head. Best oil treatment to reduce oil consumption is "Engine Restore" Used on my 58 Impala 348 tri power for 28 years. If I did not add it after oil changes it used oil and smoked....I swear by it for ANY engine after 100,000 miles.

the water pump is likely shot

make sure that the filler cap seal is in place and not gone hard over time also has the rocker cover been off at some stage if it has check that the gasket has not moved the other thing to look out for is that the PCV (breather )valve is in good working order if it is damaged the sump compression will rise and push oil out

How long is a piece of string ? without a good look under the bonnet i couldnt say but make sure the engine breather is clean and not clogged as this would cause a build up of back pressure which will cause the oil top leak from everywhere possible

(1) motor oil only smells when its being burned.
(2) the output of the air ducts is in front of the gear shift area.
So, I'm thinking that you have an oil leak in the engine compartment (which may be dripping onto the exhaust system), and the oil has found a hot part of the engine/exhaust, and the smell of heated oil is wafting through the cabin air filter into the passenger compartment through the air ducts in the middle of the dash to just above the gear shift area.
If my theory is correct, you should be able to re-route the burned oil odor by changing the setting of your air ducts by changing the setting from its current setting to a "defrost-type" setting, wherein air entering the passenger compartment comes from the ducts below the windshield, rather then entering through the openings at the center of the console.
Ultimately, your fix will be to locate and resolve the oil leak.

Here's your list of possible culprits for the 1997 Nissan Pathfinder

Priority Action Part Type Cause
1 Inspect - Valve Cover Gasket -- Valve Cover Gasket Leaking Oil.
2 Inspect - Oil Filler Cap -- Oil Filler Cap Damaged or Missing.
3 Inspect - PCV Valve -- Plugged or Damaged PCV Valve.
4 Inspect - Oil Pan Gasket -- Leaking Oil Pan Gasket.
5 Inspect - Head Gasket -- Leaking Head Gasket.
6 Inspect - Oil Pump - divided O-ring or Oil Pump Gasket

If the odor really is gear oil (aka transmission fluid) and not motor oil, then there's a leak coming from the automatic transmission/manual transaxle.
Look under the transmission after the car has been parked awhile, and look for a reddish oil spot/blot/pool. transmission fluid is dyed red just for the purpose of differentiation from other automotive lubricants. You can assist the process of color differentiation by putting newspaper under the vehicle once it's been parked for the night.
Placing enough newspaper may also keep your Pathfinder from depositing a nearly-impossible-to-remove oil stain onto your garage floor overnight.
If you already have an oil stain on the floor, try a spray can of engine degreaser first. Citrus degreaser next.

Hello,

It is located on the top of you engine compartment, under the hood, to the right (Driver Side) of the engine and left of your battery. You need to take off the plastic engine cover (two bolts and four screw nuts) to expose it. It is cylinder in shape with a black plastic cap, which screws off to show the oil filter. The filter is different than your normal one, it doesn't have a outside metal cover to it. It looks like a air filter but round. Also in the box with your new oil filter comes two "O" rings, one small and one big. The big one replaces the "O" ring at the top of the screw part of your black cap and the small one goes on the bottom of the same cap.

Take care.

Under your dash there is a small lever with a handle and marking. pull this for ejecting the bonnet. use your palm to push off the safety lack that hold the bonnet- safety for holding on during high speed/ wind if the bonnet lack opens- to lift up your boonet. You can look through the gap of the bonnet to see this safety latch.
now on top of the engine you will see the cap for the oil inlet.
Now beffore you do that , use the dip stick to look for the oil level. wipe it and check again. Only if the oil is down you need to replace. Also topping is not required unless the engine is old/bad. otherwise it is important to change the oil filter and oil along with your service. So check this out. Good day

First you have to be able to slide a pan under the engine to catch the oil, Then remove the drain plug. Let all the oil drsin out while you cjange the oil filter by unscrewing it counterclockwise. Put oil on the new filter seal and screw the new filter on as snug as you can by hand.. Put the oill pand plug back in and snug it down. Don't forget the gasket washer under the plug. Slide the pan of old oil out carefully and set it where you won't step in it. Open the hood and on one of the valve covers ia a cap about 3" in diameter. Remove the cap and look inside. If yo can see the rocker arms that is it. Put 4 quarts of new oil in it, then start it. Look underneath for any leaks. Turn the engine off and ck the oil level with the dipstick. If it is a quart low, add the fith quart. If on the full line. Add no more. Only run the engine long enough to fill the oil filter . It should only take 10 seconds. If this is a v8, it should need the fiftj quart. Put the valve cover cap back on , Put he dipsatick back in, Close the hood, and deny forgetting about the pan of oil as you step in it as you move back proud of your first oil change. Always run the engine again for 5 minutes to make sure no leaks appear. Good Luck.

Park the car on a level surface, let the engine warm up, Locate the engine-oil pan under the car, and remove the drain-plug. Put a container under the oil-pan to collect the old oil. Remove the oil-filler cap on top of engine head-cover. Remove the oil-filter by the engine block. You could grab it with one hand and turn counter-clockwise. While waiting all oil to drain out, smear some new engine oil on the new oil-filter 'o'-ring, and screw it back in place. Tighten 3/4 turn after the o-ring hits the engine surface.
Clean the drain-plug with a clean rag and tighten back in place-not over-tighten it!. Put back about 3-quarts of new engine oil through the oil-filler cap, and hand tighten the cap. Start the engine and look for leaks. After a few hours later, check the oil level. You are done!