I don’t see any lost oil dripping out from under the engine (no visible leaking and no oil spot). However it is noticeable that the oil is going somewhere when checking oil levels on the dipstick. It is using a pretty decent amount of oil too.

I believe the smell I thought was a slight smell of burning plastic or oil was related. However I only suspect this because I noticed/suspected the smell has grown worse as the oil consumption has also grown. Thus why I believe they may be related.

There is no evidence of oil in the coolant, nor exhaust. It is not “burning” oil in the engine. I suspect it is dripping somewhere I’m not noticing and getting hot enough to burn off or whatever. No oily residue in the tailpipe, nor black smoke.

Im at around 200K miles. I plan on changing the timing belt and water pump very soon. I have been tossing around the idea I’ll change the crank and cam seals while I’ve got the engine open like this, but I don’t think this will be the resolution. Because I don’t see any oil in this area (not that I really can see there until I get that side of the engine apart).

I've wondered if the rear main seal is leaking and dripping onto the exhaust or something similarly hot enough to hide the leak. Does this sound like this is the problem?

I also may need to change the accelerator position sensor, but I’m not sure if that’s the issue there. It was giving me an intermittent problem with a loss of smooth running when there was heavy rain after first starting, but that seems to have gone away.

About three months (give or take) before I noticed the smell I believe to be related to the lost oil I changed the valve cover gaskets and seals. I changed them because I had an oil fouled spark plug and coil (plus a misfire code). Haven’t had the same problem after changing the valve cover gaskets. Although admittedly I didn’t check the spark plug and coil again. I’ve just assumed it’s good because I’ve not had anymore issues with the misfire.

So it seems to be leaking exactly where you’re talking about on the left and right sides (essentially at the front and rear side of the engine because it’s sideways for the front wheel drive) just below the valve covers. The sides toward the radiator and firewall appear to be bone dry. The underside is covered in oil. I honestly hadn’t checked below before because it doesn’t drip oil when parked anywhere to my knowledge/notice. I’m not sure about the cam-thrust covers. I’ll have to figure out what/where those are exactly and look at them. I loose oil essentially as soon as I drive on the freeway or otherwise at higher rpms. It manages to always keep enough oil to read low on the dip stick (just above the lower dot). Enough to make me nervous but not enough to prevent me from driving.

I think I need to clean the oil that I see, make sure it’s got plenty of oil, and take it on the freeway and check everywhere again.

For sure! I’ll post an update and possibly some pictures of what I find...most likely this weekend if not sooner.

So I don’t seem to be able to locate the leak. It is also far slower/less than I originally thought. I have a much cleaner engine and don’t smell the burning smell. I guess I’ve just got to keep an eye on it for now and maybe catch it if or when it gets worse...