NOTE: This is based on experience with other motors, I have absolutely zero experience with the inside of a MINI motor!

A leak down test would only tell you how the rings and valves were doing. I am certain the valves are far from the first thing to suffer when oil pressure drops, and I doubt the rings get affected for a while as well.

I'd be worried about the oil pump, the rod bearings, and the main bearings. I know that in some motors you can remove the oil pan and that gives you access to remove one or more bearing caps, and then the bearings can be inspected for scuffs or unusual marks. That may not be possible in the MINI motor, though. If it is, it's a good bit of work just to do an inspection.

Checking the oil pressure can give you a rough indication of the condition of the oil pump and the main bearings (all together), but that is not as useful an indication if you don't already know what the oil pressure usually is under different circumstances. It is, however, a lot cheaper and easier than partly disassembling the motor...

Some motors are very hard on valvetrain parts, particularly rocker arms, and those can suffer when oil pressure is lost. Others are known for problems with particular bearings (e.g., the #2 rod bearing in the Porsche 944 motor) when there are oil pressure drops. I don't know what the trouble spots are on MINI motors.

Has the dealer told you why they are certain that there is no damage, even after the car was driven with the oil pressure light on? (You don't have to remind them that it was shut down immediately.) If they add details on why, that can help you understand better what is going on in there.

 

My thought is that the rings would start to suffer from the heat (I thought MCS at first). Very nice and informative post there....

The only real way to make sure things are ok is a full teardown and that certainly ain't gonna happen. Either way I wouldn't just take "it's ok" from the dealer as they don't have your best interest at heart.

I bet if Jiffy Lube did this people would yelling for them to sue! The dealer made a mistake and needs to step up. If they don't, I would contact MINI USA and see if they will work with you.

 

I think the better question here is: when the oil pressure light comes on, what EXACTLY is it signifying? Because no cars that I'm aware of will have a light come on when it's already to a point when it's beyond saving. If it came on and you had it off the road ASAP and shut off? That's what the light is for. It did its job and you followed protocol. The system worked. Unless the oil was hosing out half a quart every ten seconds, I don't see how the pressure would get to a point of damage in just that short amount of time.

Another question would be: do you have real reason to be THAT suspicious of your dealership? Were they already kind of shady to begin with? Because sure, there's plenty of CYA in this universe, but plenty of folks here have stories where their dealerships have always done right by them. If you don't have a real reason to assume the worst about them, I'm not sure why you would.

It's documented, it might be a fight if something fails in over a year's time, but then again, what fails in over a year's time might very well not have anything to do with this situation. We could play "what if" all day long but the fact remains that these are cars, and things on cars sometimes fail, and not all of those failures hinge on one incident.

 

Actually, if the oil pressure light comes on damage is already being done, especially if you have a turbo. Never trust that light to save your butt. That light means that you are running at speed and no oil is being circulated. I don't know about you, but no oil + high heat and fast moving parts is not a good combo. I certainly wouldn't trust the engine for the long haul at that point. We had a VW that had the light come on, pull over and had it repaired, engine seized a year later.

Engine oil lights are fairly pointless if you ask me. As for the rest, I could care less if the dealer was up and up or not. Once you are out the door they could care less about you and if the engine seizes 6 months down the road they will play the "it wasn't our fault" card.

You guys are too trusting. They need to protect themselves on this one not say "sounds good, thanks!" They paid good money for a car that someone else may have damaged and can't be sure it isn't as they haven't torn into it to see if that was the case. They are simply guessing as to what the internals look like. You would put your money on that?

 

Then he should have no issue with extending the warranty.

As an aside, I remember a while back that I was getting ready to fly my little Cessna and the controls were jammed against one of the stops from a gust of wind while the plane was sitting. I was able to get the controls free and they seemed to work fine, but I was nervous about whether there was any damage. I went to a mechanic and asked his opinion. He said that he was "totally sure" there was no damage and I should just go fly. I asked him to sign the logbook to that effect and he changed his tune - he spent nearly an hour doing an inspection. So much for being "totally sure".

It sounds like they've dug in their heels, so you either escalate or let it slide. That's a judgment call. Sometimes you just put your tail between your legs and live to fight a different battle.

- Mark

 

Not beyond saving, but possibly damage done. In older cars, the light will come on at very low pressures--like 3 PSI. That is not enough to maintain an oil film between bearing surfaces with any real load on them. So you are pretty much counting on the strength of the oil film itself, and that doesn't last very long when under load from the moving parts.

How long? That depends on a lot of things, like the exact loads and the oil itself and probably the phase of the moon for all I know.

When the film fails, you will have metal to metal contact. That won't make the engine explode, but it can easily scuff a small amount of material off of the bearing. That is damage, or at the very least accelerated wear.

It isn't guaranteed that this happened in this case, but it is possible.

I strongly encourage the OP to try to find out from the dealer why they are sure no damage was done. And I also encourage him/her to find out exactly what will cause that light to come on. The owner's manual may have that latter information, or it might require checking in a repair manual.

 

I know this is a old thread but you can tell if engine damage has occurred with out tearing it down. You could have sent a sample of the oil off to get analyzed that was left in the engine after the oil light came on. They can tell you how much bearing material etc is in the oil. Truckers use this all the time and it works for gas engines also.