Overfilling the oil fixes a big problem

I have a 1999 Ford Expedition with 170K miles. I drive it very gently but the car has a problem. It sometimes won’t start and makes a horrible squeliee sound when I turn the key. But over the years I’ve figured out a successful fix: (1) keep the oil overfilled by 1 - 2 quarts. (2) park on a hill, put the car in neutral, let it start rolling, and then turn the key to start the car. As I’ve mentioned, these 2 things have allowed me to continue driving the car for the past several years. The second method becomes necessary as the car burns oil and the level approaches normal. I was wondering what is wrong with the car?

I’m very curious to see what the real experts here think. My opinion is that you have (1) a bad starter motor along with (2) the placebo effect and (3) confirmation bias.

Since it sometimes won’t start and makes a sqeliee sound when you turn the key (I assume at those same times), I’d suspect a possible starter problem. Or,perhaps even an alternator problem or even a slipping belt, either of which could cause the better to not be kept charged. But hey, since it’s been doing these things for years and you’ve never bothered to check into iut, why start now?

Overfilling the oil is irrelevant. And could be harmful.

Very good :slight_smile: I understand the confirmation bias. I’ve replaced all of the electrical components (started, alternator, battery), so to the best of my knowledge I don’t believe this to be the problem.

I’ve asked mechanics about the problem, but have never been able to get an answer. And the reaction to my admittedly strange solution is always incredulous. But however strange, and for whatever reason, the two pronged approach I described seems to work.

If it helps you believe mountainbike, I’ll second the statement that overfilling the oil is completely irrelevant.

And in addition to what he mentioned regarding the squealing, if it is coming from the starter then its possible that you have a flywheel rather than starter problem - as in you lost a couple of teeth at some point.

Keep in mind that while you are in neutral and rolling downhill while trying to start the vehicle (which is very big and heavy), you have no power steering or brakes.

Could be worn out teeth on the flywheel are not contacting the teeth on the starter, or similar bad contact between the two.

Yes, thanks very much cigroller (and mountainbike). I know there is no power steering or breaks, but fortunately, I only have to let the car roll a couple of feet and it will start. Sometimes even if I’m on flat ground and encounter the starting problem, just rocking the Expedition back and forth and sometimes pushing it forward a foot or two with one of my feet out the door, and I can get it to start. Does this add to the hypothesis that the culprit could be the flywheel?

Is it difficult to check the health of the flywheel?

In neutral, the flywheel should not be turning (I think). But if it is in gear when you rock it forward and back, that definitely points to the flywheel.

Thanks StrongDreamsWaitHere, but its never in gear when I rock it back and forth or push it forward (always in neutral). If the flywheel does not turn when the car is in neutral I suppose thats evidence that it isn’t a flywheel problem?

The flywheel is always turning when the engine is running. It’s hard-bolted to the crankshaft. Cig’s suggestion of a few missing teeth is a very good possibility, and not unheard of.

To check for missing teeth basically requires removing the bottom access plate (if you have one), or removing the starter, so that you can see the gear teeth on the flywheel’s edge and turning the crankshaft by hand while looking with a good worklight at the teeth. You’ll see the missing ones.

Tip: the crankshaft is easier to turn by hand with the sparkplugs out. But you’re only going around once, so unless the crank bolt is hard to access it may not make a real difference.

I think it’s missing or worn flywheel teeth, but…

Is it possible that even in neutral a little torque can come through the trans to nudge the crank (and thus flywheel)?

Is it possible there’s a little less static friction in the engine when overfilled?
Maybe a crank throw or two dip into the oil?

I once had to have a flywheel replaced. When I examined the old one, to my surprise, it looked rather good. No missing teeth. Just some surface wear in one region of teeth. Yet the new flywheel cured all my starting problems. So even a visual inspection of your flywheel might not reveal (to the inexpert eye) that it is the true culprit.


What’s probably happening is that by rolling the car and then popping the clutch the tranny is turning the flywheel to get the missing tooth area past the starter motor and the starter can then grab normally.

I’ll toss this out. The noise could be the sprag clutch (Bendix it they still call it that) slipping. Moving the car, parking on a hill or just waiting between attempts just gives the rollers another chance to grab. Not a clue on why overfilling the oil would help. If it is the clutch, eventually it will seize and possibly take the starter motor with it.

I didn’t think Expeditions ever came with a clutch to pop.

You’re right. I made an assumption. The torque converter does retain fluid when stopped. I suppose that depending on the design o the converter it could pull the flywheel around a bit, enough to get teeth engaged when the key is turned.

I was puzzling over that as well - and am now wondering whether she wouldn’t get the same result if she just moved it out of Park - into any gear - and then back into Park & left the car stationary. I.e. as the gear shifter moves, probably through the R position, it will give the engine/flywheel a jiggle. The Neutral part may be the wrong key to the whole thing.

I’m going to guess that you have a weak transmission or engine mount, and when you put it in neutral, it takes some tension off the drivetrain and causes things to flex (or unflex if you prefer), just a tiny bit, which then lines the starter up slightly better with the flywheel, which is probably worn. I think the oil is a placebo.