HOW BAD IS OIL OVERFILL?

Not good... we specifically talked about this at the Tech Session on Saturday. I usually check mine with the engine running, at regular temps. I notice a large fluctuation between "running" and "stone cold", as you'd expect with a 348.

If you can get your hands on an oil extractor, you might be able to siphon some from the sump tank. If not, dump the oil and refill properly.

David -- please tell me this wasn't an FNA shop that overfilled it. Better yet... tell us all who did it, so we can avoid them! The oil capacities are in the OM, and it seems like whoever filled the tank didn't realize that it needs to be checked with the engine running (or at the worst, right after it's been switched off).

 

Daniel, why "not good"?

 

You have more than one car listed in your profile. I am going to assume that you are talking about 1/8 to 1/4 INCH over max. If you are talking about your 308 forget it. People often overfill their 308's on purpose to avoid oil starvation on right turns and have been doing it for several decades without problems.

If it is your 348 it will probably not cause any problems when overfilled to that small a degree. Before you let too many people freak you out, when those cars were new and I was doing PDI's on them I found the factory was routinely overfilling them by that much. Make sure you are checking it correctly and if required get a cheap suction gun and suck a little out.

 

I have accidentally overfilled my 328 about 1/2 inch. No problem at all. It took 2500 miles to go back to max (standard oil consumption...)
Daniel, why do you think that such an overfill is dangerous? I really cannot see the reason. Thank you if you will spend tim to explain.
Ciao
Eugenio

 

Yep, If you're talking 1/4 inch then forget it. if you mean 1/4 litre, it's probably still ok.

On the 308/328 it's actually advisable to slightly overfill them if you run on the track. It reduces oil surge. You can go 20mm over max without concern HOT. Any more than 20mm over could cause problems and result in oil sucking into the airbox with messy results. 20mm over when HOT (200f) is about MAX or just under when COLD.

348 or other dry sumps can be over filled too, but it is mostly unnecessary (except 360 which needs 20-30mm HOT overfill to ensure no oil surge, despite dry sump).

On all the cars, and this has been debated over and over and I'll not get into it again now, but on ALL the cars, the most reliable, consistent and generally approved way to check oil level is with oil at at operating temp (80C 200F ball park), and then check the level immediately after STOPPING the engine.

This method removes all possibiltity of human error and also return oil/waves splashing on the dipstick causing rogue readings.

My advice on oil level is based on checking it this way on any and every Ferrari ever built. If you want to take my advice you MUST follow the procedure.

But don't worry about overfill if it's under 10mm HOT on anything.

 

Maybe this is a matter of interpretation --- I read David's comments to mean, the oil is filled to the max line, then another full 1/4 amount of the dipstick -- which is about 1/2 liter (I'm guessing).

First, I doubt Ferrari puts the "max" marker on the dipstick just for grins. Maybe they're trying to keep us from spending too much money on excess oil, but I doubt it.

Second, I always thought that overfilled oil could cause excess foaming. The foam (mostly air) wouldn't lubricate very efficiently. "Accidental overfilling oil into your engine can cause problems. As the crankshaft rotates it will churn the oil, causing aeration and eventually sustained foam may form. This can lead to overheated motor oil, oxidation and a loss of oil pressure. Spongy aerated oil is hard to pump. It starves the engine and critical lubricated surfaces. "

I might be 100% wrong, and I'd welcome your comments.


-Daniel

 

On many cars an overfill (significant) can allow excess oil to enter the intake via the breather system, may cause some smoking or worse can damage the catalytic convertor. That's why most newer cars carry a sticker with that caution. Ask any Porsche 911 owner who forgot how to check his oil level.....
The overfill would need to be significant, my guess is that 1/4" on a 348 stick is under 25% of a litre.

Brian

 

On the 3x8s, like most cars, overfill becomes a problem when it's high enough to:
1) get sucked into the crankcase rebreather system
2) Get splashed by the crankshaft as it rotates. This will fill the crankcase with an oil fog that will end up in the rebreather system. It will also probably result in a slight power loss due to the energy being dissipated by splashing the oil.


There are some rathar interesting oil capacity numbers in the OM:
10 liters in the specifications column.
However, the dipstick figure has:
6 liters by the low mark &
8 liters by the full mark.

I've always considered the 10 liter number to be the amount you add when changing the filter. On my car 10 liters brings it about 18mm above the full mark before the engine is started. Once it's started, run a while, & after waiting the recommended 15min interval after shut-down it's still 12mm above the full mark.

When not changing the filter, adding 8liters will be right on or very slightly above the full mark after the 15 min. wait.

 

not even an issue

sensationalizing is all

wow

 

Extreme overfilling can cause oil foaming, with a resulting loss of lubrication. It doesn't sound like you're anywhere near that point. I once overfilled mu Mondial about one quart. My mechanic said no big deal.

 

See, David is doubly screwed... he drives a 348 AND it's overfilled with oil.

Just kidding buddy. I'm right there with ya'.



I did however, find this old picture of David's car when it was overfilled with oil last time:




















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I had a similar experience with my '79 308 - They overfilled the car by about a quart of oil when I did an oil change. I didn't check the oil level when I got the car back, I just assumed things would be ok. The next day I noticed oil leaks on the garge floor, just a few drops, but the car was completely clean with no leaks before the oil change. I took it back to the shop, they removed the excess oil and the car has almost stopped leaking. I still get an occasional drop once a week but it was completely dry before. Any ideas why this happened?