I was giving my Nissan QX an oil and filter change today. Its an all-alloy V6 with 4 chain-driven cams. Very nicely laid out and dead easy to work on.
There is one strange peculiarity though. On the front slam-panel there is a warning sticker which states "Never refill engine oil with oil level indicator removed". By 'oil level indicator' they mean dipstick. This warning in repeated in the owners manual.
I have been working on cars, both personally and 'professionally' since the early 1970's and have never come across this before. Why shouldn't the oil be filled with the dipstck removed? It is just and ordinary dipstick and pokes down into the sump in the normal way.
Can anyone suggest an explanation - its important enough for them to fit a warning sticker about it? What happens if I *do* refill with the dipstick removed?
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All I can think of is that the internal construction of the engine might lead the oil to run up the dipstick hole and overflow on its way to the sump. For example, there may be an anti-surge baffle plate over the sump which restricts the flow of oil through it and this could cause a build-up during filling that forces oil up the open dipstick hole.
My Rover 75 CDT (BMW engine) also has a strange feature, shared with other BMW engines I believe. The standard-looking dipstick shows no oil when first pulled out and needs re-inserting to get the oil level to register on it. I can't see why this is but I'm sure there must be good reason.
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My Vectra TDI has strange features with the dipstick also.
Check the level with the engine at operating temperature as per the handbook and the same as Dizzy no oil whatsoever shows on the dipstick.
Redip (if there is such a word) and the correct level shows.
I have read somewhere that Saabs who I believe fit the same engine issue a warning to owners that they must dip a few times when hot otherwise there is a danger of the owner thinking he has no oil and then overfilling.
The other thing is that checking when cold the first couple of dips gives a reading of at least 50mm above the top mark on the stick.
Repeated checks and the level becomes correct.
Like yourselves I have theorised on the plumbing and how such a simple device can have any significance.
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Hm, its possible I guess.
I know what you mean about having to re-insert the dipstick. I've come across a number of engines like that. Never really understood why it happens.
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Maybe the dip-stick seal is air-tight, so oil can't get high enough up the dip-stick tube to touch it. When you remove the dip-stick, the oil level inside the tube comes to where it should be.
Now, once you re-insert the dip-stick and start the engine, oil is distributed within the engine, its level gets low enough for air to come into the dip-stick tube and there, you start over again.
Thank you all, class dismissed ;-)
Vagelis.
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That's life, isn't it? Take something simple and foolproof, like a dipstick, that has been around for centuries. Apply modern technology to it, and turn it into an operation that needs special instructions and warning notices.
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Long Shot - there isn't a gizmo for oil level is there?
You know transducer to feed dashboard warning light for low oil level - could they be referring to this rather than the dipstick?
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No defintely the dipstick. There's a reference to it in the handbook and the sticker is right in front of the dipstick.
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Some engines have auto-dipstick wipers.....strange, I know!
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I think that Vagelis might be somewhere near the mark. Some older Peugeot engines used to take ages to refill unless you took the dipstick out - air lock.
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.........Often purely down to the poor design of the filler neck!
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