So, apparently when I checked/topped off the oil 2 weeks ago I left the oil cap off. Yesterday, on the short drive home from work, I noticed a slight sound, which I thought was a buzzing heat shield. Only heard it coming off idle Popped the hood and found the cap wasn't on. Freaked out, got oil, added about 2.5 qts to bring it back to middle of normal. That means I was running a good 2 qts low. After topping off, everything sounds normal, but I haven't driven the car yet. The "heat shield" buzz was apparently valvetrain noise, and always stopped as soon as oil pressure built. So, low is one thing, but the low oil pressure light never came on, so can I assume things were at least somewhat lubricated?


Just how badly have I screwed myself?

I'm the original owner, car is a 2002, with about 55k miles.

 

Very badly you might have most likely have some type of damage. Running low on oil is the number one killer of the f20c's

 

Only way to find out is to drive and keep your ears open. Oil pressure lights are useless, by the time they come on your motor would be a boat anchor. There are lots of stories of motors running with very little oil, I guess it depends on how high your revved it and how hard you were turning during that time. I remember reading an article about a 2011 Suzuki RMZ450 (motocross bike) that had almost no oil, it ran 30 minutes of track time before giving up.

http://www.dirtrider.com/tests/adven...m_test_update/

These have needle bearing crankshafts, but the point is that its hard to know if the motor was ever oil starved.

I would buy a real oil pressure gauge and keep a close eye on it so that you don't trash the block because of a spun bearing.

 

Depends. The rattle may have been the oil cap in between the firewall? Change oil immediately and cut open filter. Make sure also that oil cap has the little plastic gasket too.

 

The oil light indicates oil pressure, so as long as you're generating pressure, the oil is getting through the engine, so at least there's that. The down side to the low oil level is that what's in there is cycling through more frequently, which can kill the oil. Plus, I'm imagining your engine bay is a mess. Since you put oil in the engine hot, I'd wait for a cold level check and see where the oil level really is at.

What is the oil level now, and how much oil does your engine burn normally over two weeks?

 

ran mine 2 plus quarts low 22,000 miles ago. if you didnt lose oil pressure you should be good. Due to the extra punishment your oil may have been through I would do an oil change, even if your on a fresh oil change just before this occured. I would also believe the noise is not the valves but the oil cap. "listen" to the engine, you can do this by generically using a tool like a ratchet (something that would be solid from touch point to your ear) as a stethescope. Put the tool on a solid part of the engine while the car is running so you can better hear the mechanical sounds internally.

 

IMHO, you are fine. 2.5 qts added to bring it to midway means you had 3 in the engine. as long as you were not ripping turns, you'll be ok.

 

BTW, your oil cap is sitting wedged on top of the transmission, creating your buzz noise.

Very common, cap will not fall out. You need to fish it out with a coat hanger.

 

Thanks billman. You were one of the people I was hoping would weigh in. And yes, the cap was wedged between the valve cover and the firewall. Fortunately no really hard driving or cornering, mainly just short trips to work and back.

Engine seems to be purring like normal, although I'm taking it easy until I change the oil this weekend.

 

Do a compression test if you're really worried. Sounds fine though