How can I tell if i did damage by running on low oil

I just bought a 1969 austin healey sprite. I don’t have much experience with these and did something very stupid. The car has a slow oil leak. I’ve had it for 6 months and have only put about 1000 miles on it. I noticed the other day when i was on a trip that the oil pressure seemed low, but i didn’t know what it was supposed to be. It was between 10-15 lbs while driving 45 on the highway. When i got home i realized that that was very low and checked the oil. It was not on the dipstick. One quart brought it to the dipstick, 1.5 quarts brought it to the Low/OK border and two quarts put it solidly in the OK. When I run it I can’t detect any problems. I would love to be able to write this off as a lesson learned from a close call. The questtion is, how can i tell if i did damage. If I don’t detect anything the next time i drive it, does that mean that i lucked out and everything is OK?

-Paul

There is a lot to suppose here, so it’s hard to really give you a true idea of what went on in your engine. Important bits:

You actually DID have oil pressure, if not a lot, so you’ve got that going for you.
If it didn’t overheat, you’ve got that going for you.
You didn’t run it at high speeds or a very long time, so you’ve got that going for you.

If it’s not knocking, tapping, overheating, and if the oil pressure has returned to where it was, you are probably good to go. Now fix that oil leak (because on that car, I have to assume that they’ll be springing up almost as fast as you can plug them)!

Cool car. Damage from loss of oil pressure does not happen in silence. The first thing that happens is the bearings seize.

The car is running fine, likely because you never got below the oil pickup tube and never actually starved the bearings. Enjoy your ride and consider this a lesson learned, the lesson being that old cars, especially British Leyland cars, require far, far more checking, monitoring, and servicing than modern cars do. We lovers of these relics of history call this Tender Loving Care.

When the oil pressure gets too low, the engine will let you know by making knocking noises before it seizes up. You can thank your lucky stars you caught this. But the oil and filter need to be changed. The oil that saved your engine is probably burnt. And just adding fresh oil to the burnt oil just makes the fresh oil as good as the burnt oil.

Tester

You neglected to mention how FAR you drove with the low oil pressure, and this is not something you want to repeat, but as long as oil pressure was maintained and RPM kept at reasonably low levels, chances are no damage was done. As Tester mentioned, an oil and filter change is in order…

It’s been said of these early sports cars, that you can drive them flat out, have fun doing so, and never break the speed limit! The same can’t be said of present day sports cars. When driven on a twisty road, they have so much excessive power, that you can’t get them out of first gear without exceeding the laws of physics.

Thanks. In reply to hellokit’s answer, it is hard to tell how far I drove because I don’t know how long the oil pressure was that low. That trip was 45 minutes with max speed of about 55 on the highway. chances are the pressure was low through much of that. The oil is entirely clear on the dipstick. So clean that it is hard to see the mark on the stick. Probably didn’t get above 35K RPM for that trip. Most likely, there were previous trips with slightly more pressure, but still on the low side, as the oil has been getting lower slowly.

Experience # 1. This post reminds me of a long time ago in the mid 1970s when my wife and I rented a car in LA, a Ford Pinto while my wife was there for a convention. We drove quite a few miles, freeway and city streets. I noticed that first day that the oil light would light occasionally when approaching a red stoplight. Eventually we stopped for gas as we must have used a tankful and so we also took the time to check the oil. We were young, in a new place in a rented car; were excited from the trip and from being in LA for the first time and so we just blew off the oil light; what did we know about Ford Pintos so we didn’t check the oil sooner. The dipstick showed no oil. As I recall, enough oil was added to make me believe that the rental car had been in for an oil change but no new oil was added.

The engine made no odd sounds before and after the crankcase was filled at the gas station. I’m guessing that there might have been about a half quart in the crankcase and that the filter had not been changed. It could be a good guess that someone who would forget to fill the crankcase would also not want to wait long enough for all of the old oil to drain.

Experience #2. Also a number of years ago I did a small favor for one of my wife’s friends who was newly divorced; did a little work on her car and also checked her car’s oil while she was at our house. The car was a Plymouth Horizon with a VW made engine. I added three quarts to bring it up to full. Those VW engines still had the bad valve stem seals that deteriorated and made them oil burners. I reminded her friend to check the oil once in a while. Her engine also made no strange noises.

My guess too is that your engine is fine.

I’ll agree with everyone else. Since you had oil pressure and driving at comparatively low speeds I think you’ll be fine also.

Neat car; not many Austin Healey Sprites around here anyway. A now defunct body shop here used to have a near complete one and a pair of rolling parts cars just sitting out in their impound lot. They would not cover them up, fix them, or sell them. Hopefully when they shut down someone bought them and preserved or restored them.

Don’t know if you’re familiar with them or not but here’s a parts source.
http://www.victoriabritish.com/

I’ve dealt with them half a dozen times with never a problem.