Need laymans terms answer to oil level question.

[RedM]

With a cool engine my oil level was near the lowest mark. I added 1.5l and it was up to the max mark. I take it the other 4.5l + that goes in there is elsewhere. Is that correct? I remember reading somewhere that if it's at the low point when cool then you've lost about a litre. Right again?

 

Also, with engine warmed up the level drop to near the low point again. That's okay isn't it? Oil moving around the engine etc and then it'll pool up at whatever point and the dipstick reading goes up for the cold engine reading.

[AndrewOW]

You're probably correct.

 

 

 

 

 

I just thought someone should reply

[JustGav]

Your dipstick doesn't go to the very bottom of the sump, the 'excess' oil that you aren't seeing will be below the dipstick. Remember also when the car has been running, the oil will be washing round the internals and will pool in the galleries and things like that.

 

The difference between min and max is around 1l or so.

[RedM]

Your dipstick doesn't go to the very bottom of the sump, the 'excess' oil that you aren't seeing will be below the dipstick. Remember also when the car has been running, the oil will be washing round the internals and will pool in the galleries and things like that.

 

The difference between min and max is around 1l or so.

 

So, does that mean the oil level light comes on when only a litre is missing because to lose any more would mean that there isn't enough to go round the engine and that I don't need a 5l 'top-up'?

[georigg]

Assume the oil all drains back into the sump when the engine is cold, then you will have 4.5 Litres of oil in the sump.

 

The total oil capacity of the "system" is that of all of the parts of the car that oil travels through when the engine is running, and that comprises the oil filter, oil cooler, engine galleries and for turbo cars, the turbo.

 

If you assume the average oil filter holds about 1/2 a litre(probably less), the oil galleries are very small and the space between big ends, bearings etc is also "very small".....measured in thousands of an inch, the oil cooler will similarly hold a "very small volume(see the Technical section for volume) then adding all of these up will give you a rough idea of how much oil is "in circulation" when the engine is running.

 

I would be surprised if its more tha one litre in total, unless you have a very big and non standard oil cooler fitted.

 

In reality, the oil filter should retain its oil as will/should the oil cooler, so as these are likely the largest "volume" items, you should not see a big reduction in oil volume in the sump, between engine static and engine running.

 

Remember that the "oil Level" indicator(and associated switch) is located between the sump and the oil pump, with the oil pressure linicator(and associated pressure switch) located after the oil pump and before the oil filter.

 

If you have the oil level light coming on but still have NO oil pressure light(engine running) then I would suspect a faulty oil level switch, if the oil level light AND the oil pressure light are both on then you would appear to have a major problem.

 

I normally start the engine from cold(mornings) and as soon as the engine fires, switch it off again, and then re-start it. Reason:- At start from cold, Toyota engines appear to be susceptible to "running" at initial start up with a "lag" in the oil pressure...........you may hear a "rattle" at start-up, that's the big ends and main bearings running without any oil pressure for about 1-2 seconds as oil pressure builds up.

 

Starting as above, allows the engine to turn-over without firing, which allows oil to establish in the galleries without the increaased pressure from a "firing engine" and gives a little better protection to the bearings.

 

Also, if you use after-market oil filters, they have a habit of draining down ovwer-night where-as OE fitlers tend to retain oil in them, which helps reduce this phenomenon at start-up(this is a function of the "rubber flap" non return in the oil filter which tends to be less effective in non OE filters).

 

Hope you find the above helpful.

Rgds

Georigg