Engine oil overfill?

Question

In my Ford Focus owner's guide it says this about checking the engine oil level :

"For an exact reading a cold engine should be run for a short time. Switch the ignition off and wait some minutes for the engine oil to flow back into the sump."

Does this mean that some of the oil will still be in the upper part of the engine so that if you checked the oil stone cold, it would be alright to go slightly above the maximum mark on the dipstick ?

Answer 1

You have a lot of things to worry about!?

... Oil can be checked hot or cold, --( if engine hasn't been run.) --If it has , - dependiong on how cold it is, - and amount of blockage in "return holes" to crankcase (oil pan) some oil will be sitting on top of head, but unless you are in below freezing weather it will generally be a small amount, and will run back down for most part in less than 5 minutes!

Most "dipsticks" have a range marked on stick that is "safe" (whether hot or cold). Some even have a hot&cold indication (oil expands just a little when hot). So it is possible to have oil level at "safe" -lower range of indicator, - and then if you start it and run for a minute or less, - then pull stick it will indicate slightly below safe range. You will also notice that it comes up with a lot of oil on dipstick also (because oil is runing back down into engine). the colder the oil is the longer it will take for it (oil level)- to come up with most of oil on stick, -- (at "oil level")- since oil all over stick makes it hard to tell what the level is at all!)

On "overfull" -it is not good for engine to have it "overfull" by a large amount, - since first of all your engine crank is "running underwater",- this will cause you to have a considerable loss of power,-- and a lot of oil is splashed up on cylinder walls, and may make exhaust "smoke" to some degree also! Now I am talking about a quart or more too much! But most worriesome problem is that the pressure may blow out "main seals' on crankshaft, which makes a nasty messy leak, and causes engine to lose a lot of oil rather rapidly, -(depending on how bad the leak is).. Repair can be expensive,- front isn't too bad,- can replace in a couple hours on most cars, - bur rear main seal, requires removing transmission to get to it on most cars!

All the information book gives is correct, - however it is somewhat confusing,-- if you don't understand how system works!

By the way on cold engine that has been run, it will indicate lower (from full mark) becacuse the oil is "on top", -not in oilpan, so don't add till a reasonable time has passed for oil to "drip" back down to bottom!

Note information about automatic transmission also, --it says engine must be running, (and run from reverse to drive several times), - this is because it normally pulls oil up into "converter" (which couples engine to transmission). (&) If checked without engine running it will give you a "false reading" - saying transmissin is "over full" (if actually full), - & possibly full -( if it is actually dangerously low)!!

Answer 2

Ford Focus engine oil & filter change query?
I have a quick question about my Ford Focus 1.8 petrol. I have just had my car serviced and checked the oil level myself before I left the garage (when it was cold) . It was minutely about the max mark on the dipstick, so I wasn't too concerned. I checked it again after it had been left standing overnight outside my house and found it was slightly higher than at the garage. When they change the oil/filter does some of the oil they add remain in the oil filter until the engine has been running and is that the reason for the higher level ?

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There was probably oil still in the engine and filter when you checked it at the garage. After leaving it overnight, it has all drained back into the sump, giving the slightly higher reading. When they fit the new filter, they usually "prime" it with some of the new oil, and this would take time to drain back to the sump.

Answer 3

Just keep it between the max and min marks on the dipstick, hot or cold. There's no benefit in overfilling above the max mark, don't bother yourself with trying to work out how to squeeze a couple of mils more in. The engine manufacturers have made all the necessary allowances.

Answer 4

It is not that critical (we're not worried about a couple of millimetres on the dipstick).

If the engine is overfilled, the first consequence will be excess heat being generated by the crankshaft and big ends thrashing about in the excess oil.

If the engine is further overfilled, engine oill can be blown along the crankcase breather, and end up being sucked into your inlet manifold. Then it passes through your cylinder and blown into the exhaust pipe. This will permanently clog your catalytic converter, which is expensive.

Answer 5

It's fine. I assume that from this & your previous postings, you're new to cars. It will be absolutely fine to have 10mm above the line, and the engine should be fine down to the minimum level - ordinarily, it shouldn't use or lose any oil between services, so don't worry unless it drops by an inch overnight! And DON'T take it to a Ford dealer for simple jobs - they'll just take the mickey on pricing, a rocker cover gasket would cost about £25 fitted in most places, I assume you'll have paid somewhat more.

Answer 6

What this is saying, is that if you are adding oil, they recommend running the engine for a minute and letting it sit for @ 20mins. This allows all the oil to drip back into the pan.

If you just want to check be4 adding oil, and the vehicle has been sitting a while, there wont be any in the block. Your reading should be accurate.

Answer 7

Every manufacturers specify slightly different method for using dipsticks. As long as you follow them exactly, you will be OK, as they were calibrated using the described method.

It will be OK to SLIGHTLY overfill it. I wouldn't go more than 1/16" more than the MAX mark. If you over do it, it will starts to burn oil, which will damage many things in exhaust system, and if you really over do it, you will damage the whole engine to a point rebuilding is not even possible. Besides, there is no benefit in filling it over the recommended mark. (usually between max and min mark.

Answer 8

Depending on whether diesel or petrol, A deisel needs longer to check the oil level and the check time for a deisel after switching off whether hot or cold should be approx. 5 minutes. Petrol takes less time 3 minutes approx. =)

Answer 9

Maximum means that, dont overfill you may risk blowing various seals/gaskets. Do as instructed and run the engine till it is warm then fill to max when the oil has settled.

Answer 10

do not overfill with oil. You will waste oil, and risk spillage and a smoky engine.

You run the engine to ensure that oil is at the right temperature and density to judge its volume.